tankjkt spreadsheet template heat for · pdf filetemperature, jacket heat transfer...

UINS‐TJ‐02 February 2015 1

TANKJKT spreadsheet template

Heat Transfer Calculations for Jacketed Tanks

Copyright 2001, 2015 by Stephen Hall, PE

Introduction

TANKJKT is an easy‐to‐use powerful spreadsheet template that calculates the rate of heating or cooling

of tanks due to heat transfer from jackets and internal coils.

Vessel heat transfer is complicated. It involves five resistances to heat flow each of which is dependent

on specific conditions. Correlations have been developed for many different cases (e.g., half‐pipe coil

jackets, turbine impellers, etc.). But other cases (dimple jackets, conventional jackets with nozzles) are

either poorly researched or are proprietary and not available for use in this, or any, open product.

Our challenge when designing TANKJKT was to keep the data entry as simple and intuitive as possible

while maintaining a comprehensive feature set. We think you'll agree that this goal was met.

Data Input is gathered onto a single worksheet, described in detail in these instructions. The results of

the calculations are given on a "datasheet" that matches the look of all of chemengsoftware.com's

spreadsheet templates.

Fluid Data are included for most common heat transfer fluids. Because the data is regressed against

temperature, jacket heat transfer calculations are very fast, accurate, and easily tested with alternative

fluids.

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Table of Contents

Quick Start ........................................................................................................................................................................................ 3

Quick Results .................................................................................................................................................................................... 4

System Requirements ....................................................................................................................................................................... 5

Orientation and Initial Setup ............................................................................................................................................................ 6

Data Input Worksheet ...................................................................................................................................................................... 8

Vessel Data ................................................................................................................................................................................. 10

Jacket ......................................................................................................................................................................................... 12

Half‐Pipe Coil Jacket (Limpet Coil) .............................................................................................................................................. 12

Conventional Jacket ................................................................................................................................................................... 13

Dimple Jacket ............................................................................................................................................................................. 14

Bottom Head Jacket ................................................................................................................................................................... 14

Internal Coils .............................................................................................................................................................................. 15

Heat Transfer Fluid ..................................................................................................................................................................... 15

Flow Rate Data ........................................................................................................................................................................... 15

Vessel Fluid Data ........................................................................................................................................................................ 18

Agitator Data .............................................................................................................................................................................. 19

Environmental Conditions .......................................................................................................................................................... 20

Datasheet ........................................................................................................................................................................................ 21

Timeline .......................................................................................................................................................................................... 23

Flow Rate Calculations .................................................................................................................................................................... 25

Experimentally Determined Pressure Drop ............................................................................................................................... 26

Outside Heat Transfer Calculations ................................................................................................................................................ 27

Half‐Pipe Coil Jacket (Limpet Coil) .............................................................................................................................................. 27

Conventional Jacket ................................................................................................................................................................... 27

Dimple Jacket ............................................................................................................................................................................. 29

Internal Coil ................................................................................................................................................................................ 29

Inside Heat Transfer Calculations ................................................................................................................................................... 30

Agitator Power Calculations ........................................................................................................................................................... 34

Agitator Power Transferred to the Process Fluid ....................................................................................................................... 35

Depth of Vortex ......................................................................................................................................................................... 35

Fluid Data Worksheet ..................................................................................................................................................................... 36

Data Tables Worksheet ................................................................................................................................................................... 40

PictElements Worksheet (HIDDEN) ................................................................................................................................................. 40

Saved Calcs Worksheet ................................................................................................................................................................... 41

Result Details .................................................................................................................................................................................. 41

Nomenclature ................................................................................................................................................................................. 43

References ...................................................................................................................................................................................... 45

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Quick Start

Perform your first heat transfer calculation by following these steps:

1. Ensure that Macros are enabled

2. Navigate to the Data Input worksheet

3. Use the dropdown boxes, radio buttons, check boxes and input fields to enter data about your

tank and fluids. Input fields are displayed in RED text.

4. See the results!

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Quick Results

Results are displayed on the Data Input worksheet. These can be printed, but the intent is to give

immediate feedback so changes to the inputs can be made before finalizing the calculation and printing

a datasheet.

The heat transfer film coefficients are listed for the process and heat transfer fluid sides of each heat

transfer surface. TANKJKT uses these, together with wall resistance and fouling, to calculate the overall

heat transfer coefficient, U.

Next, the flow rate, velocity and pressure drop for each of the surfaces are reiterated. The values are the

same as those in the “Flow Rate in Side‐Wall Jacket” section described previously.

The temperature and heat flow results are listed for each heat transfer surface and the top head. Inlet

and outlet temperatures for the heat transfer fluid are given, along with the amount of heat transferred

through each surface. A positive value for heat transfer indicates a heating effect; negative means

cooling. When combined with power input from the agitator, the total heat transfer is computed. Based

on the volume of process fluid that was input in the “Vessel Data” section, the instantaneous rate of

heating or cooling is calculated and displayed.

The picture of the tank provides visual confirmation that the jacket, coil, baffles, impeller and liquid level

are configured as you intended. This picture is not to any scale except that the blue shading indicating

fill level accurately indicates the percent of sidewall covered by liquid.

You might see messages on screen, just to the right of the “Vessel Fluid Data” input area. When present

they warn of unusual or unexpected parameters that you might want to correct.

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System Requirements

Personal computer running Microsoft Excel with Visual Basic for Applications (VBA). This

requirement means that Open Office and other programs capable of opening and editing basic

Excel worksheets will not work – VBA is required. Excel 97 on the Mac lacks VBA and is therefore

incompatible, however Office 2010 on the Mac is compatible

Excel must be configured to allow macros to run. This can be done through Security settings, or

by enabling macros each time TANKJKT is opened

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Orientation and Initial Setup

TANKJKT consists of six main worksheets. When you open the program you must enable macros, if your

Excel security settings are set to Medium or High. The Data Input worksheet should then be displayed.

The main worksheets are:

Data Input Enter tank, agitator and fluid (heat transfer fluid and process liquid) on

this worksheet, and view the calculation results

Datasheet Print a datasheet that documents the configuration of the tank system

and presents the heat transfer calculation results

Timeline Create and print a datasheet that shows the temperature change of the

process fluid over time

Fluid Data Add new heat transfer fluids to the database

Data Tables See lookup values for various parameters. This worksheet contains

intermediate calculations

Saved Calcs Saved calculations are stored on this worksheet

Although TANKJKT is ready to use immediately, there are a few things you might want to adjust to

improve your experience.

Change the Logo You can replace the chemengsoftware logo on the datasheets with your own

logo. First, unprotect the datasheet. Then right‐click on the logo followed by

left‐click on the logo. This selects it without opening the hyperlink. Hit the

Delete key to get rid of it, then paste your own logo in its place. Please

remember to protect the worksheet again so you don’t make inadvertent

changes to it.

Enter company info This is a good time to customize your copy by entering your basic company

information into the “Project Data” section on the Data Input worksheet.

Set up the printer Select all of the worksheets and then use the print settings dialog to establish

your paper size. As shipped, TANKJKT is configured for U.S. 8½” x 11” paper.

Outside of the U.S. you will probably want to choose A4 size.

Configure decimals TANKJKT uses the function “=TEXT(value, format)” for many of the displayed

numbers, especially on the datasheets. For example, the formula

=TEXT(PI(), “0.00000”)

displays the value of π to five decimal places, 3.14159.

If you are in a country that uses a different convention than the U.S. for

displaying thousand separators or decimals, then you’ll want to change this.

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Your computer country setup does not affect the TEXT formulas as used in

TANKJKT.

We provided an easy‐to‐use tool to adjust the formatting in TANKJKT. Instead of

hard‐coding the number formats in all those =TEXT formulas, we use a named

cell value to get the format. These are found on the Data Tables worksheet,

right at the top of the page. In the yellow field you can change any of the values

in RED to a format of your choosing. The Name (e.g., N1Format) is what the

format cell is named in the spreadsheet. So the TEXT formula for the π example

would be:

=TEXT(PI(), N5Format)

To use a comma for the decimal separator, simply edit the cell next to N5Format

to be: 0,00000. Name FormatN1Format 0.0N2Format 0.00N3Format 0.000N4Format 0.0000N5Format 0.00000T1Format #,###T2Format #,##0.0T3Format #,##0.00DateFormat dd-mmm-yyyy

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Data Input Worksheet

All of your project and calculation case data are entered on the “Data Input” worksheet. The worksheet

is designed to simplify your task in assembling the large amount of information needed for a

comprehensive calculation. Where your possible input is limited to a specific list of choices (such as

materials of construction), TANKJKT presents the choices in the form of check boxes, radio buttons, or

dropdown lists. Other data entry fields are checked as you enter data, with unexpected inputs (i.e.,

those outside “normal” ranges programmed into the spreadsheet) flagged with Warning messages.

The complete Data Input worksheet is pictured on the next page. Your screen is probably too small to

display the entire Data Input sheet at once. Use the vertical and horizontal scroll bars to reach all of its

parts.

You should notice right off the little red triangles that appear in some cells. These indicate that there are

“comments” associated with the cell. By hovering your mouse pointer over the cell, the comment box

appears, usually with guidance on how to fill in the cell. For example, the comment associated with

surface roughness lists values in both Customary US and SI units for several common vessel materials.

Here is a rundown of the Input sections, working from the top left of the screen, down the left side,

followed by the middle column and then the right column.

Project data is used in the header section of

the datasheet output form. But the data are

not involved in any calculations. It is

recommended that the text strings be short

to ensure they fit within the rather small

boxes on the datasheet. Look at the

datasheet to see how it fits.

The radio buttons toggle between “Customary US” and “SI” units of measure. When you switch from

one to the other all data input data are converted also, so you can freely toggle back‐and‐forth.

Project DataPrepared by SMH Client Hypo

Date 1/22/2015 W.O. 01-155

Unit 15

Area B

Equip No T-126Customary US SI

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Vessel Data

Physical information about the vessel

construction is entered here. When running

multiple cases on the same vessel, this section

will usually remain constant.

The “Calc Title or Description” is used on the

Datasheet. You can enter a lengthy

description that covers an entire line of the

printout. See the Datasheet, just above Line 1,

for an example.

TANKJKT always assumes the vessel is

oriented vertically and is cylindrical. Changing

this value has no effect.

The “Total working volume” is used to calculate the rate of heating or cooling. TANKJKT uses this

number to estimate the fill height, and if the jacket covers tank wall that isn’t wetted on the inside then

that portion of the jacket is ignored. A warning is displayed if the input for working volume fills the tank

higher than the top tangent (where the top head curvature begins), and the volume of the tank to the

top tangent (including the bottom head) is displayed for reference.

Inside diameter and tangent‐to‐tangent dimensions are used for many calculations and are critical input

values. They are typically near a 1:1 ratio; very tall tanks (beyond about 3:1 height:diameter) and very

squat tanks (1:2) are processed by all of the formulas, but use caution because the underlying heat

transfer correlations, especially for the inside heat transfer coefficient, may not be very accurate under

those conditions.

Choose the type of head on the tank bottom using the dropdown list. The top head is immaterial to the

calculations except for heat gain/loss to the environment (which is usually small compared with the

total). The bottom head type is used for calculating the fill height and the surface area for the bottom.

Material of construction for the tank wall is selected from the dropdown list. Wall thickness is important

because it impacts the overall heat transfer coefficient. It is assumed that in internal coil is made of the

same material as the tank wall.

An inside lining may be selected from the dropdown list, or choose “None” from the list. Linings are

typically glass, a polymer such as Teflon, or an exotic metal such as tantalum. Again, enter the thickness

of the lining.

Some suggestions are given in the pop‐up comment box for typical roughness values. Consider how the

tank will be maintained, and the condition of the surface after a period of time. Similarly, fouling factors

are entered. You should consider how the condition of the jacket might change over time (e.g., are there

corrosion inhibitors in your water?), and cleaning practices for the inside of the vessel. For instance in

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pharmaceutical, cosmetic or food processing where cleanliness is exceptionally important it is

reasonable to set the “internal fouling factor” to zero. If you are uncertain what values to use for

roughness or fouling, try running the calculation with alternatives to see the effect on your results; this

will help you decide on an appropriate figure.

The check box is used to signify the presence of internal baffles. Propeller and turbine agitators usually

work much better with baffles, however if none are present TANKJKT uses appropriate correlations.

Since baffles cannot be used with helical ribbon or anchor type impellers, the baffle checkbox is ignored

in those cases. And glassed retreat curve impellers are normally accompanied by a “finger” style glassed

baffle; the checkbox is ignored for the glassed retreat curve impeller case and it is assumed that there is

a baffle.

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Jacket

This part of Data Input has a general section,

then additional sections for each of the three

types of sidewall jackets. There’s another

section for the bottom head.

If you know for certain what type of jacket

your tank will have then focus just on the

corresponding input section. However, if you

intend to compare one type with another, be

sure to complete all relevant sections.

Use the radio buttons to select what type of

jacket is on the tank. The dropdown list of

inlet/outlet nozzle sizes is only used for

conventional annular jacket types.

Sidewall jackets are often broken into

separate “zones” for the purpose of

decreasing the temperature change in the

jacket fluid or to decrease pressure drop. The

TANKJKT calculation procedures don’t

differentiate between stacked and interleaved

zones, so it doesn’t matter what type your

tank uses. Enter the percentage of the

sidewall covered by the jacket; it’s usually “1”,

but can be any value from 0.1 to 1.0. For

example, if the jacket only covers half the

height of the sidewall, enter the value “0.5”.

Half‐Pipe Coil Jacket (Limpet Coil)

Half‐pipe coil jackets are normally constructed

of 3‐inch pipe; TANKJKT permits 2, 3 or 4‐inch.

Additional sizes may be added (see the

section on Data Tables, page 40).

The cross section angle is either 180 degrees

(a true “half‐pipe”), or 120 degrees. Enter the appropriate value. This has a big impact on pressure drop,

but not so much on the heat transfer coefficient. So when designing a new vessel, you want to compare

the effect on temperature change of the jacket fluid (typically much higher with the 120 degree angle).

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13

The last data to enter is the spacing

between adjacent coils. This is the actual

distance between coils on the surface of

the tank, not the distance between

centerlines. It is typically in the range of ¾

to 1½ inches (20 to 40 millimeters).

Conventional Jacket

“Conventional” jackets are found on glass‐lined vessels and also often when the primary purpose for the

jacket is heating with steam. The jacket consists of an outer shell separated from the vessel wall with an

open space (the “annular” space).

TANKJKT recognizes three mutually exclusive cases:

A standard conventional jacket

A conventional jacket with internal baffles that direct the jacket fluid around the vessel, similar to a half‐pipe jacket

A standard conventional jacket with “agitating nozzles” that impart turbulence to the entering fluid.

The “annular space dimension” is the distance between the outside of

the vessel wall to the inside of the jacket wall.

If the “Baffled” checkbox is selected, a prompt appears for “baffle

spacing.” This is the distance between adjacent baffles.

If the “agitation nozzles” checkbox is selected, prompts appear for

entering the number of agitation nozzles and the throat diameter of

each nozzle. Input the number of nozzles on the sidewall, ignoring the

bottom head. TANKJKT makes a simplifying assumption that if there is a bottom head conventional

jacket it will have the same nozzle configuration as the sidewall. By “same” is meant that there are the

same number per unit area, rounded up to the next integer. Even if the conventional jacket is

continuous around the bottom head and sidewall, as is usually the case, ignore the bottom head for the

purpose of this entry.

The throat diameter of the nozzles are assumed to be uniform for all nozzles. Refer to the pop‐up

comment for typical values.

The remaining checkbox in this section is “Aiding Flow.” Since standard conventional jackets have such a

large cross‐sectional area, they typically operate in the laminar flow regime, at a velocity around 0.03

m/s (0.1 ft/s). When working in cooling service, if the coolant enters the bottom of the jacket and flows

upward it will heat along its travel. This causes the fluid to expand slightly, giving it a buoyant force, and

increasing its velocity. As a result the heat transfer coefficient from the jacket fluid to the tank wall is

Tank Wall

120 deg180 deg

Tank WallJacketWall

Baffle

BaffleSpacing

AnnularSpace

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increased slightly. The opposite occurs when coolant flows from top to bottom, and heating applications

work in reverse.

Dimple Jacket

Dimple jackets are often a good choice, combining low cost with excellent heat transfer. Unfortunately,

the correlations published for dimple jackets are less reliable than for half‐pipe coils, perhaps only +/‐

30% accurate. This is true for heat transfer coefficients and also for pressure drop. So, for critical

applications always consult with the tank manufacturer.

Enter the requested data. Annular space is the maximum distance between the tank wall and the jacket.

Distances between dimples is measured as if a square grid were placed over the jacket wall (i.e., not the

actual distance between dimples in the case of triangular pitch). And the mean dimple diameter is a

measure of the space occupied by the dimple and surrounding depression. Thus, by manipulating the

values for dimple diameter, spacing, and annular space, you affect the calculation for open area

available for flow through the jacket.

Bottom Head Jacket

While normal practice is to match the bottom head jacket with the sidewall, TANKJKT supports a

different type. Thus, you could specify a conventional jacket on the bottom head coexisting with a half‐

pipe coil on the sidewall.

Use the radio buttons to select the type of bottom head jacket to model. Whichever type is chosen, the

physical parameters are assumed to be the same as those specified for the sidewall jacket of like type.

The only other decision to make is whether the bottom head will be piped in series or parallel.

TANKJKT uses this flow information when it

computes the flowrate through the jacket sections. In

each case, the flow through the sidewall jacket (if

any) is calculated first. Then, the bottom head jacket

is calculated.

In series flow, the flowrate through one of the

sidewall zones is forced through the bottom jacket.

This may result in a ridiculously high pressure drop in some cases, which means that you must make

different design decisions with respect to series/parallel, jacket types, or how the flow is determined

(see section on jacket fluid flow, on page 25).

Series Flow

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Internal Coils

Internal coils are helical

when high heat transfer is

required, or hairpin when

the heat duty is low.

Typically, the coil diameter

is 1/30 of the vessel inside

diameter, and the coils are

spaced so that the distance between them equals their diameter.

The flowrate through the coil is determined by criteria established in the Jacket Fluid Data section.

Heat Transfer Fluid

TANKJKT includes a database with physical

properties of many heat transfer fluids

correlated with temperature. This is a

valuable feature because it makes

comparison of different fluids at different

temperatures so easy and fast. You might

even find yourself turning to TANKJKT just to

look up physical properties of an included

fluid.

All major heat transfer fluids sold in 2012 are in the database. For the glycol‐based low temperature

fluids such as Therminol FS, properties are given for a range of concentrations.

In addition, non‐proprietary chemicals such as water, steam, ammonia, alcohols, etc. are found in the

database. See the complete list on the next page. You can add more compounds to the database. See

the Fluid Data section (page Error! Bookmark not defined.) for instructions on how to add your own.

On the Data Input screen simply choose a fluid from the dropdown list, then enter the bulk temperature

of the fluid supply. Properties are automatically filled in.

The only condensing vapor supported by TANKJKT is steam. Heat transfer fluids such as Dowtherm A

that can be used in vapor/liquid service are not supported at this time.

Flow Rate Data

In the second part you provide your

instruction on how to compute the fluid

flowrate. For each heat transfer surface, you

specify the flow rate, velocity, or pressure

drop. TANKJKT calculates the other two

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parameters. The value you enter is shown in RED and the two calculated values are in BLACK. You can

enter a value into a black cell – it will turn RED and the other two values are calculated and displayed in

BLACK. Try it!

When there are multiple sidewall zones, the total flow entered is divided among the zones and pressure

drop is calculated for each zone. TANKJKT assumes that sidewall zones are piped in parallel. If you want

to pipe them in series, with flow leaving one zone then entering the next, you must specify ONE Sidewall

Zone.

Engineers commonly pipe the heat transfer surfaces in parallel and may, or may not, install control

valves or orifices to manage the distribution of the flow. If you do not intend to install restricting

devices, then specify the same pressure drop through each of the surfaces. TANKJKT then calculates the

flow rates and velocity through each; this might help you decide if orifices or valves are needed.

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Table 1: List of Heat Transfer Fluids Included in TANKJKT (you can add more)

Air

Ammonia

Argon

Butane, iso‐

Butane, n‐

Calflo AF

Calflo FG

Calflo HTF

Calflo LT

Carbon Dioxide

Chemtherm 550

Dowfrost HD, 10 vol%







Dowfrost, 10 vol%

Dowfrost, 20 vol%

Dowfrost, 30 vol%

Dowfrost, 40 vol%

Dowfrost, 50 vol%

Dowfrost, 60 vol%

Dowfrost, 70 vol%

Dowfrost, 80 vol%

Dowfrost, 90 vol%

Dowtherm 4000, 10 vol%









Dowtherm A

Dowtherm G

Dowtherm HT

Dowtherm J

Dowtherm MX

Dowtherm Q

Dowtherm RP

Dowtherm SR‐1, 10 vol%









Ethane

Ethylene

Hitec

Ilexan S

Jarytherm AX320

Jarytherm BT06

Jarytherm DBT

Marlotherm LH

Marlotherm N

Marlotherm P1

Marlotherm P2

Marlotherm SH

Marlotherm X

Methane

Mobiltherm 603

Multitherm IG‐2

Multitherm PG‐1

Nitrogen

Oxygen

Paratherm HE

Paratherm NF

Paratherm OR

Propane

Propylene

Refrigerant R‐11

Refrigerant R‐113

Refrigerant R‐114

Refrigerant R‐12

Refrigerant R‐123

Refrigerant R‐124

Refrigerant R‐13

Refrigerant R‐134a

Refrigerant R‐152a

Refrigerant R‐22

Steam

Syltherm 800

Syltherm HF

Syltherm XLT

Syntrel 350

Thermalane 550

Thermalane 600

Thermalane 800

Thermalane FG‐1

Thermalane L

Thermia Oil B

Therminol 55

Therminol 59

Therminol 66

Therminol 75

Therminol D‐12

Therminol FS, 20 wt% pg





Therminol LT

Therminol VP‐1

Therminol XP

Water

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Vessel Fluid Data

The fluid inside the vessel is the process fluid.

This is the material that you want to transfer

heat to or from. Process data are not stored

in the program, so unlike the heat transfer

fluid you must enter data for the important

physical properties.

The values for thermal conductivity, specific

heat and density are taken as constants over

the range of temperatures considered by the

program. Therefore, you should enter values

that are appropriate for the temperature of

interest.

Viscosity, on the other hand, varies dramatically with temperature.

There are two ways to enter viscosity.

In the input box shown above, enter the viscosity at 20°C. TANKJKT

estimates viscosity at other temperatures with the Lewis and Squires

temperature correlation [Poling].

The formula for this chart is:

233

202661.020

2661.0 T

T

The second way to enter viscosity is to

provide the viscosity at three temperatures.

TANKJKT constructs a formula, just as it does

for heat transfer fluids, to predict the

viscosity at other temperatures.

These values must be entered using the units

that are shown, and you must tick the

checkbox for “Use this data”. You can test the

validity of the formula by entering a

“temperature of interest” and seeing the

result.

Finally, by ticking the “Use properties of water” checkbox, all other values are overridden; water

properties are used.

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Agitator Data

Choose the type of impeller from the

dropdown list. When you change impellers,

input fields for the relevant data are

presented; fill in the information that is

requested. There are hundreds of types of

impellers in industry; TANKJKT offers choices

from the most common types. If your impeller isn’t listed, pick one that has similar characteristics for

flow pattern (axial or radial) and category (turbine or close‐clearance).

Impeller geometry is usually specified within standard ranges that are tied to the tank diameter. Some

of the calculations take geometric values into account, but others ignore geometry because the effect is

small. The most important parameter for calculating heat transfer and power is the Reynolds number

which is computed from the impeller diameter, speed and properties of the process fluid (viscosity and

density). Those are the four parameters that are most important and should be specified reasonably

accurately.

Table 2: Impeller Types in TANKJKT

Alloy 3‐blade retreating. This is similar to a glass‐steel retreat‐blade impeller, but

constructed of stainless steel or some other alloy. Radial flow.

Anchor. Generally used for viscosities from 20,000 to 100,000 cP, anchors are lower cost

than helical coils, and often provide better heat transfer. Close proximity.

Glass‐steel retreating. This is the workhorse impeller for glass‐lined reactors, although this

is changing with the introduction of new impeller styles and materials. Heat transfer is

worse than with the alloy retreating blade style (above) which is attributed to more

slippage around its curved surfaces. Radial flow.

Helical Ribbon. This proximity type of agitator is generally used for higher viscosity fluids

(100,000 to 1,000,000 cP, except highly non‐Newtonian liquids which tend to rotate with

the impeller and are sheared near the vessel wall. Close proximity.

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20

No Agitator. Inside heat transfer coefficients are low when there is no agitation.

Paddle. Very similar to a turbine, but with only two or four blades. Generally with a

diameter greater than 0.6 of the tank diameter, turning at a slow speed. Radial flow.

Propeller. Applicable when the viscosity is less than about 2000 cP, and for vessel volumes

less than 6000 liters (1500 gallons) and vessel diameter < 1.5 m (5 ft) because they weigh

much more (e.g., cost more) than turbines. Axial flow.

Pumped Circulation (no agitator). TANKJKT does not model circulation with jets, but

instead treats this as liquid flowing through the vessel as if it were a large pipe.

High‐Efficiency Hydrofoil. These are designed to provide more streamlined flow compared

to pitched‐blade turbines or propellers. They have three or four tapering twisted blades,

sometimes with rounded leading edges. Axial flow.

Pitched‐Blade Turbine. The pitched blades are typically mounted at a 45°angle. Angles <

30° or > 60° are extremely rare. Axial flow.

Pitched‐Blade Turbine (Rushton). The blades are sometimes mounted on a flat disk and

typically have 4 or 6 blades (can range from 4 to 12). Radial flow.

Impeller photos from [Dickey]

Environmental Conditions

Enter the tank’s exterior environment in this

section. If indoors, set wind speed to zero.

Select insulation and the insulation covering

from the dropdown lists. Uninsulated surfaces

are also assumed to be unpainted. The

surface treatment sets the value used for

emissivity, which enters into the radiation

heat loss/gain calculation. You can review and

change the emissivity values on the Data Tables worksheet.

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21

Datasheet

The datasheet organizes your pipe information on a form that has the same look as datasheets used

throughout the chemengsoftware family.

Information in the header section needs to be edited manually for your needs. If the cells are locked,

simply Unprotect the sheet (there is no password needed) before editing the information.

Notice that there are three triangles with numbers. These can be copied and pasted on top of the

datasheet to indicate revisions

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23

Timeline

The timeline datasheet is the same as the primary datasheet, except the heating/cooling curve is

substituted for the calculated results. TANKJKT creates the curve by updating the temperature of the

process fluid at time increments entered by the user. At the beginning of each time increment, TANKJKT

evaluates the physical properties of the process fluid at the temperature and calculates the rate of heat

gain or loss. Then, the temperature at the end of the increment is calculated using that rate and the

time increment. The new temperature is substituted into the Data Input worksheet and the calculation

is performed again. This repeats until 61 increments are computed. The results are charted.

The results are also tabulated near the bottom of the Data Tables worksheet. Go to the named cell

“interval_time” to quickly find the tabulated data.

At the top of the Timeline worksheet, enter a value for the calculation interval in Cell B2. Then click the

“NEW TIMELINE” button. The calculation takes several seconds – up to a minute on very slow machines

– so be patient while the timeline data is generated.

Typical results are pictured on the next page.

TANKJKT

24

TANKJKT

25

Flow Rate Calculations

The flow rates through each section of the jacket or inside the coils must be determined before the

overall heat transfer is computed. TANKJKT support a limited number of permutations that are

described here. We decided to favor a more simple user input at the expense of limiting the flexibility of

specifying each jacket zone and coil flow individually.

As seen in the screenshot below, you can enter the flow rate, velocity or desired pressure drop for each

surface. The program calculates the other two. In this example, the flow for the sidewall and bottom

head jackets are specified and the velocity through the internal coil is also specified.

Flow Rate in Side-Wall Jacket

Enter a value for each heat transfer surface. When one parameter is entered (f low ,

velocity, or pressure drop) the other tw o are calculated. Red value show s user entry.

Total Flow Velocity Pressure Drop

Sidew all Jacket 80.0 liters/min 0.7 m/s 1.7 kPa

Bottom Jacket 60.0 liters/min 1.1 m/s 0.9 kPa

Internal Coil 116.9 liters/min 0.9 m/s 3.2 kPa

Here, the pressure drop for all three surfaces is specified. You can enter values in any of the nine fields

(3 surfaces x 3 parameters). As soon as a new value is entered, the cell turns red while the other two

values for that surface turn black and are calculated.

Notice that in this example the flow rates for the sidewall and bottom jackets are approximately equal

but the velocity for the sidewall is half that of the bottom jacket. The reason for this is that, for this

example, the sidewall is specified to have two zones. The flow is divided equally between the zones, so

the flow through each of the two sidewall zones is half of what is shown.

Flow Rate in Side-Wall Jacket

Enter a value for each heat transfer surface. When one parameter is entered (f low ,

velocity, or pressure drop) the other tw o are calculated. Red value show s user entry.

Total Flow Velocity Pressure Drop

Sidew all Jacket 549.9 liters/min 4.9 m/s 80.0 kPa

Bottom Jacket 552.5 liters/min 9.8 m/s 80.0 kPa

Internal Coil 586.1 liters/min 4.5 m/s 80.0 kPa

In the special case with one sidewall zone, if you check the “Series Flow” box under Bottom Head Jacket,

then the flow rate in the sidewall and bottom jackets are equalized. For instance, if you enter a flow rate

for the bottom jacket then the flow for the sidewall is immediately changed to equal it. If you enter a

value for pressure drop through the sidewall, the sidewall jacket flow is calculated and displayed, then

the bottom jacket flow rate is set equal to that calculated value.

TANKJKT

26

Bottom Head Jacket

No Jacket

Half-Pipe Coil

Conventional

Dimple

Same type as Side-Wall Jacket

Series Flow

The flow rates, velocities and pressure drops are all calculated using physical properties at the

temperature of the HTF supply. Strictly speaking, the density and viscosity will change as the HTF cools

or warms through the jacket, but these differences are not accounted for. We elected to make this

simplification because the effect on the overall heat transfer calculations is insignificant.

The flow rate, velocity and pressure drop calculations are contained in the “JacketFlow” subroutine (and

supporting functions) found in the “FlowRate” VBA module.

Experimentally Determined Pressure Drop

If you have data for pressure drop through

the jacket, then use it to possibly improve the

reported flow and pressure drop results. The

input box for experimental data is located in

the center column at the bottom.

Enter the four pieces of data requested: flow rate, viscosity, density and pressure drop, all at the

experimental conditions. Then select the checkbox. TANKJKT computes an “equivalent length” for the

jacket flow path, using the hydraulic diameter and flow area that are calculated from the jacket

dimensional data. It’s important to enter the jacket dimensional data (described previously) because this

determines a Reynolds number which, in turn, is important for calculating the friction factor.

If there are multiple zones, enter the flow rate and pressure drop for one zone. If there are multiple

nozzles (conventional jacket), enter the flow rate for a single nozzle. For example, if you have a jacket

with two agitating nozzles and you know the total flow rate is 200 liters/minute with a total pressure

drop of 50 kPa, then enter 100 for the flow rate (200 divided by 2) and 50 for the pressure drop. Don’t

divide the pressure drop in two.

Use this section when you have experimental pressure drop dataInput the known conditions

Flowrate Viscosity Density Press Drop Use Experimentalliter/min mPa-s g/cm³ kPa Pressure Drop Data

Sidew all 150.0 1 1.0 50.0

(one zone)

Bottom Head 85.0 1 1.0 45.0

See the instruction manual for further information about the use of this pressure drop technique

Sidewall

Bottom Head

TANKJKT

27

Outside Heat Transfer Calculations

The outside heat transfer coefficient refers to the heat transfer fluid side of the surface, whether it be

outside the tank wall or the inside of an internal coil. This section gives the method used to calculate the

outside coefficient for each type of surface.

Half‐Pipe Coil Jacket (Limpet Coil)

Turbulent flow is expected, and is modeled, for both sidewall and bottom head, with Gnielinski:

1Pr87.121

Pr1000Re8325.0

f

f

k

dh eo [1]

Garvin’s presentation includes a correction factor for helical coils that accounts for improved heat

transfer due to centrifugal forces on the outside of the coil. Since the outside of a jacket coil faces away

from the tank we elected to ignore this factor. It is documented in the “HTFSideh” subroutine and may

be restored by removing the comment apostrophes at Lines 10 and 20.

' 10 CurvDiam = T / Cos(Atn(2 * H3 / cdPI / SidewallZones / NoCoils / T)) ' 20 A = 1 + 0.059 * (Re * (HydDiamFlow / CurvDiam) ^ 2) ^ 0.34

If the flow is laminar (Re < 2100), then the following equation is used [Dream]:

14.033.0

PrRe86.1

w

eeo

L

d

k

dh

{2}

Conventional Jacket

We follow [Garvin 1999] for the conventional jacket calculations. Conventional jackets may be strictly

annular, fitted with internal baffles, or equipped with agitating nozzles. Annular jackets often operate in

the laminar flow or transitional flow range, so the heat transfer algorithm is more complex than those

seen for other jacket types. The internal baffle jacket is modeled like a half‐pipe coil, except that

because the baffles don’t form full channels there is bypass flow that must be accounted for. Agitating

nozzles provide turbulent flow and are considered to be the driving force for heat transfer.

Conventional Annular Jacket

The algorithm follows this path:

1. Calculate the equivalent diameter and curvature diameter of the jacket

2. Determine limits for Laminar, Transitional, and Turbulent regimes

a. Lower limit for Turbulent regime is Re = 15000

b. If 307.0c

ed

dthen the Laminar regime extends all the way to Re = 15000

TANKJKT

28

c. Otherwise the upper limit of the Laminar regime is calculated with

6.0

min 2.1312000Rec

earla d

d

d. The Transitional regime is between the upper limit of Laminar to 15000

3. Calculate Nu for the Laminar regime (if Re < 15000) using the value of Re or, if in the Transitional

regime, at the Re at the upper limit of the Laminar regime

a. Let

25.0

5.0 PrRe

c

e

d

dX

b. If X > 4.9 (high curvature) then

14.0

432

2121202.2348.11984.0

wXXXXXNu

c. If X <= 4.9 (low curvature) then, for aiding flow the sign is plus (+) and exponent m is

0.28, and for opposing flow the sign is negative (‐) and exponent m is 0.25

14.0

67.00525.0109525.086.4

w

fc Gz

GzNu

Iteratively calculate Nu using

888.0

4875.0expGz

Nu

m

enc L

dGrNu

Pr7287.0 33.0

31

33ncfc NuNuNu

4. Calculate Nu for the Turbulent regime (if Re > 15000) or at a Re = 15000 if in the Transitional

regime

a. Let

2

Re

c

e

d

dX

TANKJKT

29

b. If X > 4.72 (high curvature) then, if this is a cooling application (HTF temperature is less

than the process temperature), set Ge = 1 and m = 0.18. For a heating application, set

Ge = 1 and m = 0.3

c. If X <= 4.72 calculate

e

e

d

L

L

dGe 07.0exp171.51 and m = 0.18

d. Then

34.02

2495.0795.0 Re059.01Prln0225.0expPrRe0192.0c

e

m

w d

dGeNu

5. For the Transitional regime, interpolate between the Nu calculated at the Laminar and

Turbulent limits from above against the logarithm of Re.

Conventional Jacket with Baffles

This case uses the same formulas as the half‐pipe coil jacket [Garvin 1999].

Conventional Jacket with Agitating Nozzles

TANKJKT follows the method given by [Garvin 2005] for conventional jackets with agitating nozzles. The

method uses data for pressure drop and flow rate given by the tank manufacturer such as Pfaudler or

De Dietrich. That data is given for the case of water, usually at 20°C, and TANKJKT uses it to calculate the

effective nozzle outlet diameter. As Garvin states, this value is related to, but not equivalent to, the

throat diameter of the nozzle.

When nozzles are used you can either enter a value for throat diameter, which is taken to be the

effective outlet diameter in the calculation, or enter pressure drop data with water (viscosity = 1 cP and

density = 1 g/cc) in the “Experimental pressure drop” section of the Data Input worksheet.

Dimple Jacket

Using the mean dimple diameter as the characteristic length, applicable to sidewall and bottom head

[Garvin 2001]:

33.0695.0

383.0

max

min

368.0

PrRe0845.0

A

A

x

w

k

dh oo [3]

Internal Coil

This case uses the same formulas as the half‐pipe coil jacket [Garvin 1999]. For a helical coil we applied

the centrifugal force correction factor.

TANKJKT

30

Inside Heat Transfer Calculations

The inside heat transfer coefficient refers to the process side of the surface, whether it be the tank wall

or the outside of an internal coil. The general form of the coefficient, for agitated vessels, is:

c

w

bai Kk

Th

PrRe [4]

The coefficient, K, and exponents a, b, and c vary with the type of agitator impeller and which surface is

under consideration Geometric corrections are made, depending on the impeller, for deviations from

“standard” values for parameters such as blade width, blade height, impeller diameter, baffle width, etc.

Typical values for K are 0.5 (baffled tank, axial‐flow impeller), 0.75 to 0.80 (baffled tank, radial‐flow

impeller) and 0.35 to 0.4 (unbaffled tank regardless of impeller type). Typical values for a, b and c are

0.67, 0.33 and 0.14.

The calculation utilizes physical properties of the liquid inside the tank, evaluated at the bulk

temperature plus the viscosity evaluated at the wall temperature. The wall temperature varies with the

amount of heat transfer, so the calculation is iterated. The first pass sets the wall temperature to the

average of the process fluid bulk temperature and the heat transfer fluid supply temperature. After the

inside and outside heat transfer coefficients are evaluated, the overall heat transfer coefficient is

calculated and a new wall temperature determined. This is used for the second pass and the calculations

are repeated until the algorithm converges, which takes only three or four iterations.

For radial flow impellers, different coefficients for the sidewall and bottom head surfaces are reported.

TANKJKT uses those different coefficients or uses identical coefficients if the literature doesn’t specify a

difference.

The coefficient for tanks without agitator use natural convection correlations for natural convection at

vertical or horizontal surfaces (sidewall and bottom head respectively). These make use of the

dimensionless Grashof number that relates buoyancy and viscous forces acting on the fluid. Instead of

the bulk liquid temperature used for agitated vessels, the film temperature, defined as the average of

bulk and wall temperatures, is used to evaluate the necessary physical properties: volumetric thermal

expansion coefficient and kinematic viscosity.

For the tank sidewall, setting L = wetted height of sidewall, we use the Churchill and Chu formulas which

are [Welty]:

For [Gr Pr} < 109,

94

169

25.0

Pr492.01

Pr67.068.0

Gr

k

Lhi [5]

TANKJKT

31

For [Gr Pr} > 109,

2

278

169

61

Pr492.01

Pr387.0825.0

Gr

k

Lhi {6}

For the bottom head, we use the simplifying assumption that it is a flat horizontal plate, with the

characteristic dimension, L, equal to the ratio of tank bottom area divided by its perimeter. The

formulas are [McAdams, Lloyd]:

For tank cooling,

25.0Pr27.0 Grk

Lhi [7]

For tank heating, with [Gr Pr} < 2 x 107

25.0Pr54.0 Grk

Lhi [8]

With [Gr Pr} >= 2 x 107

31

Pr15.0 Grk

Lhi [9]

Pumped circulation is treated as a combination of natural and forced convection. The natural convection

component is calculated as described above. For forced convection, we make an assumption that the

vessel contents move as if flowing in a pipeline. This results in a laminar flow condition, and the film

coefficient for laminar flow is computed with:

33.0PrRe

86.1

L

T

k

Lhi [10]

This result is combined with the natural convection result. In practice, the forced convection component

makes no practical difference and might as well be ignored.

For unbaffled tanks, if published data weren’t found we used a correction factor of 0.65 for the sidewall,

and 1.0 for the bottom head.

TANKJKT

32

Table 3: Parameters for Sidewall Inside Heat Transfer Coefficient

Impeller K a b c Other Reference

Alloy 3‐blade retreating 0.37 0.67 0.33 0.24 [for 6‐blade, K‐0.37, c = 0.14] Dream

Anchor 0.69 0.5 0.33 0.14 Re < 100 Penny 2004

0.32 0.67 0.33 0.14 100 <= Re < 300 Penny 2004

0.33 0.67 0.33 0.18 300 <= Re < 4000 Dream

0.55 0.67 0.25 0.14 4000 <= Re Dream

Glass‐steel retreating 0.54 0.67 0.33 0.14 Couper

Helical ribbon 0.94 0.33 0.33 0.14 Re < 13 Penny 2004

0.248 0.5 0.33 0.14 13 <= Re < 130 [(T‐D)/(2D)]‐.22(Pitch/D)‐.28

Dream

0.238 0.67 0.33 0.14 130 <= Re (Pitch/D)‐.25

Dream

Paddle 0.415 0.67 0.33 0.24 Re <= 4000 Dream

0.36 0.67 0.33 0.14 4000 < Re Dream

Propeller 0.5 0.67 0.33 0.14 Baffled tank (T/Z)0.15 [1.29 (Pitch/D)]/[0.29 (Pitch/D)]

Penny 2004

0.313 0.67 0.33 0.14 Un‐baffled tank (T/Z)0.15 [1.29 (Pitch/D)]/[0.29 (Pitch/D)]

High‐Efficiency turbine 0.31 0.67 0.33 0.14 (W/0.17D)0.2 (T/Z)0.15 Penny 2004

Pitched‐blade turbine 0.45 0.67 0.33 0.14 (W/0.17D)0.2 (T/Z)0.15

Disk turbine w/6 blades 0.74 0.67 0.33 0.14 Re <= 400, Baffled tank (W/0.2D)0.2 (T/Z)0.15

[for 4‐blade, K = 0.66]

Penny 2004

0.85 0.66 0.33 0.14 400 < Re, Baffled tank (T/Z)‐.56 (D/T)0.13

Dream

0.54 0.66 0.33 0.14 Un‐baffled tank (T/Z)‐.56 (D/T)0.13

Dream

Table 4: Parameters for Bottom Head Inside Heat Transfer Coefficient


Alloy 3‐blade retreating 0.37 0.67 0.33 0.24 [for 6‐blade, K‐0.37, c = 0.14] Dream

Anchor 0.69 0.5 0.33 0.14 Re < 100 Penny 2004

0.32 0.67 0.33 0.14 100 <= Re < 300 Penny 2004

0.33 0.67 0.33 0.18 300 <= Re < 4000 Dream

0.55 0.67 0.25 0.14 4000 <= Re Dream

Glass‐steel retreating 0.54 0.67 0.33 0.14 Couper

Helical ribbon 0.94 0.33 0.33 0.14 Re < 13 Penny 2004

0.248 0.5 0.33 0.14 13 <= Re < 130 [(T‐D)/(2D)]‐.22(Pitch/D)‐.28

Dream

0.238 0.67 0.33 0.14 130 <= Re (Pitch/D)‐.25

Dream

Paddle 0.415 0.67 0.33 0.24 Re <= 4000 Dream

0.36 0.67 0.33 0.14 4000 < Re Dream

Propeller 0.5 0.67 0.33 0.14 Baffled and un‐baffled tank (T/Z)0.15 [1.29 (Pitch/D)]/[0.29 (Pitch/D)]

Penny 2004

High‐Efficiency turbine 0.9 0.67 0.33 0.14 (W/0.17D)0.2 (T/Z)0.15 Penny 2004

Pitched‐blade turbine 1.08 0.67 0.33 0.14 (W/0.17D)0.2 (T/Z)0.15 Penny 2004

Disk turbine w/6 blades 0.5 0.67 0.33 0.14 Baffled tank and un‐baffled tank (W/0.2D)0.2 (T/Z)0.15

[for 4‐blade, K = 0.4]

Penny 2004

TANKJKT

33

Table 5: Parameters for Helical Coil and Hairpin Coil Process‐Side Heat Transfer Coefficient


Alloy 3‐blade retreating 0.03 0.67 0.33 0.14 No correlation found in literature; using 6‐blade disk turbine parameters without geometric corrections

N/A

Paddle 0.027 0.67 0.33 0.14 (W/0.2D)0.2 (T/Z)0.15(T/D)0.5 Penny and Fair

Propeller 0.016 0.67 0.33 0.14 (3D/T)0.1(CoilD/T/0.04)0.5 Penny 2004

High‐Efficiency turbine 0.017 0.67 0.33 0.14 (W/0.17D)0.2 (T/Z)0.15(T/D)0.5 Penny and Fair

Pitched‐blade turbine 0.023 0.67 0.33 0.14 (W/0.17D)0.2 (T/Z)0.15(T/D)0.5 Penny and Fair

Disk turbine w/6 blades 0.03 0.67 0.33 0.14 (W/0.2D)0.2 (T/Z)0.15(3T/D)0.1

(CoilD/T/0.04)0.5(2/#Blades)0.2 Penny 2004

Proximity impellers are not compatible with helical coils, so anchor and helical ribbon impellers are excluded from the TANKJKT

model. Internal coils are not generally used with glass‐lined vessels, and they are not modeled for glass‐steel retreating

impellers.

Table 6: Parameters Baffle and Harp Coils Process‐Side Heat Transfer Coefficient


Alloy 3‐blade retreating 0.021 0.67 0.4 0.14 No correlation found in literature; using 6‐blade disk turbine parameters without geometric corrections

N/A

Paddle 0.06 0.65 0.3 0.14 (W/0.2D)0.2 (T/Z)0.15(3T/D)0.33

(CoilD/T/0.04)0.5 Penny and Fair

Propeller 0.016 0.67 0.33 0.14 (3D/T)0.1(CoilD/T/0.04)0.5 Penny 2004

High‐Efficiency turbine 0.017 0.67 0.33 0.14 (W/0.17D)0.2 (T/Z)0.15(T/D)0.5 Penny and Fair

Pitched‐blade turbine 0.023 0.67 0.33 0.14 (W/0.17D)0.2 (T/Z)0.15(T/D)0.5 Penny and Fair

Disk turbine w/6 blades 0.021 0.67 0.4 0.14 (W/0.2D)0.2 (T/Z)0.15(3T/D)0.1

(CoilD/T/0.04)0.5(2/#Blades)0.2 Penny 2004

Proximity impellers are not compatible with helical coils, so anchor and helical ribbon impellers are excluded from the TANKJKT

model. Internal coils are not generally used with glass‐lined vessels, and they are not modeled for glass‐steel retreating

impellers.

TANKJKT

34

Agitator Power Calculations

Agitator power (kW or hp) for turbine s is calculated from the general relationship:

c

P

g

DNNP

53 [11]

The power number, NP, is given in many sources and generally considered to be a constant for a specific

impeller when operating in the turbulent region (Reynolds number > 20,000). At lower values of

Reynolds number the same relationship applies, but the power number increases. However, the reason

for a lower Reynolds number may be a decrease in speed or impeller diameter, both of which enter into

the power relationship, so this is complicated.

A generalized graph of power number as a function of Reynolds number is widely published and

reproduced below. We fit fourth‐order polynomials to the curves and use those to estimate the power

number after calculating the Reynolds number. The power numbers are adjusted for factors such as

number of blades and blade width.

Figure 1: Power numbers for turbine impellers [Dickey]

TANKJKT

35

Agitator Power Transferred to the Process Fluid

You can configure the amount of the agitator power that is transferred to the process fluid as heat. On

the Data Tables worksheet you’ll find a cell named AgitatorPowerCooling and another named

AgitatorPowerHeating. These represent the percentage of the agitator power that is added to the

process fluid as heat. A rule of thumb is that 50% of the motor power is transferred, but we suggest

conservative values of 55% for a cooling application, and 35% when heating.

Depth of Vortex

For unbaffled tanks with turbine type impeller, TANKJKT estimates the depth of the vortex using the

relationship from Rieger. This estimate is provided for information only and should not be taken as an

absolute given. The result appears in the list of messages, just to the right of the Vessel Fluid Data on the

Data Input worksheet.

The correlation uses the Galileo and Freude numbers as follows.

For high Ga,

008.014.1

38.0069.0 008.0

D

TFr

D

TGaBDDepth Ga

H [12]

For low Ga,

24.038.3

18.133.0 074.0.

D

TFr

D

TGaBDDepth Ga

L [13]

The values for BH and BL depend on the impeller style as does the breaking point value between a high

and low Ga number.

TANKJKT

36

Fluid Data Worksheet

Physical properties for heat transfer fluids are tabulated on the “Fluid Data” worksheet. These are

regression parameters that TANKJKT uses to determine the properties at any temperature. You can add

new fluids to this worksheet using the tool that described in this section.

Properties are returned with the following units:

Temperature ____________________________ °C

Density ________________________________ lb/ft3

Specific Heat ____________________________ Btu/lb‐°F

Thermal Conductivity _____________________ Btu/ft‐hr‐°F

Viscosity _______________________________ cP

Vapor Pressure __________________________ mm Hg

Beginning with Version 2.1, all calculations are performed in SI units then converted to Customary US for

display and reporting. Therefore, the function subroutines that utilize the properties on the “Fluid Data”

worksheet return the results in SI units. We retained the Customary US units on “Fluid Data” to ensure

backward compatibility; a user may safely copy‐and‐paste regression coefficients from a previous

version of TANKJKT.

The viscosity and vapor pressure are not actually regressed. Instead, three values are forced to fit a

three‐parameter equation. Viscosity is divided into three temperature ranges so there are three sets of

parameters. This isn’t actually necessary – excellent agreement between data and correlation are

obtained with a force fit over a large temperature range – but to maintain backward compatibility the

practice is continued in the program.

Here are the equations used to fit the data, where t = temperature, °C:

Density btm

Specific Heat btmc p

Thermal Conductivity btmk

Viscosity

15.273

exptC

BA

Vapor Pressure tC

BAP

TANKJKT

37

Example

Thermal physical properties for Paratherm HE® are published on the Paratherm web site

(http://paracalc.paratherm.com) and reproduced below. For this example, we chose seven

temperatures and the properties for viscosity, density, thermal conductivity and specific as highlighted.

Notice that the vapor pressure data is listed only at high temperatures.

Screen shots showing this data entered onto the “Fluid Data” worksheet are shown and described on

the next page.

UINS‐TJ‐02 February 2015 38

Units that the original data are in:

Temperature

Density

Specific Heat

Thermal Conductivity

Viscosity

Fluid Name: Paratherm HEManufacturer: ParathermDescription: Mineral oilOperating range: 50 °C minimum

310 °C maximum

Liquid Thermal VaporTemp. Density Sp. Heat Conduct. Visc. Pressure

°C kg/cu.m. Btu/lb-°F Btu/ft-hr-°F cSt mm Hg

38 850 0.47 0.075 4566 830 0.49 0.074 16 0.07

107 810 0.53 0.0724 5.5149 780 0.56 0.071 2.9 19.50191 750 0.6 0.0695 1.8246 720 0.65 0.0675 1.1 422.00316 670 0.71 0.065 0.7

degrees F degrees C

lb/cu.ft. kg/cu.m.

Btu/lb-F = cal/g-C Kj/kg-K

Btu/ft-hr-F W/m-K

cP centi Stokes = mm2/s

Add Fluid to Database

The radio buttons are used to select units of

measure consistent with those in the published

data. Density is published in g/cc, but we

selected kg/m3 instead and multiplied the

density values by 1000 when entering them in

the table.

After entering all of the data, we clicked on the

“Add Fluid to Database” button. This adds a

new line to the properties table and enters the

parameters for all of the properties.

The four graphs confirm that the data is entered

correctly since there are no obvious outlying

data points. Notice, however, that the values

entered for thermal conductivity at 107°, 191°

and 246°are slightly higher than those in the

published table. This was done to compensate

for the lack of significant figures in the data and

create a better match between data and

regressed parameters.

0

100200

300400500

600700

800900

0 100 200 300 400

Density

Density Predicted

00.10.20.30.4

0.50.60.70.8

0 100 200 300 400

Specific Heat

Specific H eat Predic ted

0.064

0.066

0.068

0.07

0.072

0.074

0.076

0 100 200 300 400

Thermal Conductivity

Thermal Conductivity Predicted

0.1

1

10

100

0 100 200 300 400

Viscosity

Viscosity Predicted

TANKJKT

39

Vapor pressure data is entered separately in this example. The temperatures for three vapor pressure

points are entered along with corresponding values for vapor pressure, as shown below.

Fluid Name: Paratherm HE <-- Already in the databaseManufacturer: ParathermDescription: Mineral oilOperating range: 50 °C minimum

310 °C maximum

Liquid Thermal VaporTemp. Density Sp. Heat Conduct. Visc. Pressure

°C kg/cu.m. Btu/lb-°F Btu/ft-hr-°F cSt mm Hg

288 21.00

316 52.00

329 79.00

Take the following steps to get the results into the table:

1. Unprotect the worksheet if necessary. Review … Unprotect Sheet. There is no password.

2. Copy the three Antoine Coefficients to the clipboard. These are found on row 55, beginning in

column G (unless you have inserted rows and/or columns to the worksheet).

Antoine Coeff icients

A B C

88.65765 539906.1 5893.983

3. Use Paste Special … Values to paste the coefficients into the row for the fluid (in this example,

Paratherm HE). This overwrites the values that were (incorrectly) placed there when the fluid

was added initially.

For this illustration the unneeded values for density, specific heat, etc. are erased from the input data

table. In practice this isn’t necessary since only the vapor pressure (and corresponding temperatures)

are actually used.

TANKJKT

40

Data Tables Worksheet

The Data Tables worksheet stores parameters for physical properties such as thermal conductivity of

tank materials, emissivities, standard pipe sizes, and agitator geometries. You can edit some of these

values, but be very careful that you don’t overwrite formulas that calculate the dimensions of tank

heads, or values that save previous data entries for impellers. In general, don’t change values on this

worksheet.

The worksheet also stores the value of radio buttons, dropdown lists and check boxes. These are

controlled by associated control on the Data Input worksheet and should not be edited.

The timeline values are written to this worksheet with the results used to create the timeline chart.

Again, these are programmatically determined and should not be manually edited.

Refer to the Data Tables worksheet for additional information about the values that are stored there.

PictElements Worksheet (HIDDEN)

The PictElements worksheet is hidden from view and should not be changed. It contains the pictorial

elements used to compose the tank picture on the Data Input screen. These elements are copied from

this worksheet to the Data Input worksheet whenever needed to refresh the picture.

TANKJKT

41

Saved Calcs Worksheet

It takes time to enter all the data about a particular

vessel. That’s why you have the option to save that

data for reuse in the future.

Data is stored on the worksheet called “Saved Data”.

When you click on the “Save Calculation” button on the

Data Input sheet, the current calculation is instantly

copied to the Saved Data page. You must save the

entire workbook to keep access to this data for the future!

Retrieving an old calculation is simple. Choose it from the dropdown list of saved data, then click the

“Restore Saved Calculation” button. That’s it.

To delete old calculations from the archive, go to the Saved Data worksheet. Unprotect the sheet (there

is no password required). Then highlight the row(s) containing your unwanted data. Delete the row(s) by

using Excel’s Edit…Delete… command.

Result Details

TANKJKT stores the results from calculations in an array. You can view the complete content of the

array, displayed in the units that are currently selected, on the worksheet called “Result Details.” You

can also write your own formulas to tap into the results.

The syntax for the formula is:

= Res(surface, parameter, units, chng)

The arguments are:

surface is the heat transfer surface, where 1 = sidewall, 2 = bottom, 3 = coil, 4 = tank roof

parameter is the value (see list below)

units is the units of measure for the result, where 1 = U.S., 2 = SI

chng is a reference to a cell that updates whenever the calculations are run, which forces this

formula to refresh

TIP: Store information about commonly

used classes of vessels. TANKJKT is shipped

with physical dimensions of standard glass‐

lined vessels manufactured by Pfaudler

and De Dietrich (USA). Similarly, you can

add to this the types and sizes of vessels

TANKJKT

42

Table 7: Parameters Stored in the Res() Array

Parameter Description U.S. Units SI Units

1 HTF Film Coefficient, ho Btu/hr‐ft2‐F W/m2‐C

2 Process Film Coefficient, hi Btu/hr‐ft2‐F W/m2‐C

3 Overall Coefficient, U Btu/hr‐ft2‐F W/m2‐C

4 Heat Transferred, Q Btu/hr W

5 HTF Flow Rate lb/hr kg/h

6 HTF Pressure Drop psi kPa

7 HTF Velocity ft/s m/s

8 HTF Temperature In F C

9 HTF Temperature Out F C

10 HTF Temperature Average F C

11 HTF Temperature Wall F C

12 Process Temperature F C

13 Process Temperature Wall F C

14 Wall Coefficient, hw Btu/hr‐ft2‐F W/m2‐C

15 Agitator Power Surface 1 = total power Surface 2 = power as heat to fluid

Btu/hr W

16 Environmental film coefficient, he Btu/hr‐ft2‐F W/m2‐C

17 Jacket‐to‐environment Ue Btu/hr‐ft2‐F W/m2‐C

18 Jacket‐to‐environment Qe Btu/hr W

19 Process‐to‐environment Ue Btu/hr‐ft2‐F W/m2‐C

20 Process‐to‐environment Qe Btu/hr W

21 Surface Temperature F C

The function EnergyResult returns the final results for the calculation. Its syntax is:

= EnergyResult(parameter, units, chng)

The arguments are:

parameter is the result requested, where 1= total energy gained or lost from the process fluid in

the tank, and 2= temperature change per minute

units is the units of measure for the result, where 1 = U.S., 2 = SI

chng is a reference to a cell that updates whenever the calculations are run, which forces this

formula to refresh

TANKJKT

43

Nomenclature

Note that the units associated with the variables are not entirely consistent. Formulas used in the

TANKJKT calculations recognize this and apply the necessary conversions. In some cases, the units used

on the Data Input sheet differ from those used in the VBA subroutines. For example, impeller diameter

is input in millimeters, but converted to meters when transferred to the subroutine.

pc specific heat, Joules/kg‐°C

D impeller diameter, m

g acceleration of gravity, 9.81 m/s2

cg conversion factor, 1 m/s2

ih inside (process‐side) heat transfer coefficient, W/m²‐°C

oh outside (heat transfer fluid side) heat transfer coefficient, W/m²‐°C

k thermal conductivity, W/m‐°C

K coefficient for heat transfer equation

L characteristic length, m

N agitator rotational speed, rps

P agitator power, W

T inside diameter of vessel, m

t temperature, °C

U overall heat transfer coefficient, W/m²‐°C

W blade height, measured parallel to shaft, m

Z liquid depth in the tank, m

For conventional jackets

cd curvature diameter

ed equivalent diameter

hd hydraulic diameter = 2 x annulus

L length of the flow path from entrance nozzle to exit nozzle

For dimple jackets

odwzA min minimum flow area

TANKJKT

44

wzA max maximum (unrestricted) flow area

od mean dimple diameter, m

w center‐to‐center distance between adjacent dimples parallel to flow

x transverse center‐to‐center distance between adjacent dimples

Greek variables

coefficient of volumetric expansion, 1/°C

density, g/ cm3

dynamic viscosity, Pa‐s

Dimensionless numbers

DN

Fr2

Froude number

FrGa

2Re Galileo number

2

23

tLg

Gr

Grashof number

L

dGz hPrRe Graetz number

k

ThNu i Nusselt number

ND 2

Re Reynolds number

k

cp Pr Prandtl number

TANKJKT

45

References

Bolliger, Donald H., “Assessing heat transfer in process‐vessel jackets,” Chemical Engineering,

September 20, 1982, page 95.

Bondy, Frederick, and Lippa, Shepherd, "Heat transfer in agitated vessels", Chemical Engineering, April 4,

1983, page 62.

Cau, Eduardo, Heat Transfer in Process Engineering, McGraw‐Hill, 2010.

Couper, J.R., Penny, W.R., Fair, J.R., Walas, S.M., Chemical Process Equipment: Selection and Design, 3rd

Edition, Butterworth‐Heinemann, Waltham, MA, 2012.

Dickey, David S., “Mixing and Blending,” from the Kirk‐Othmer Encyclopedia of Chemical Technology,

Wiley, published online 16 Apr 2010.

Dream, Robert F., "Heat Transfer in Agitated Jacketed Vessels", Chemical Engineering, Vol 106, No 1,

January 1999, pages 90‐96.

Furukawa, H., Kato, Y., Inoue, Y., Kato, T., Tada, Y., Hashimoto, S., "Correlation of Power Consumption

for Several Kinds of Mixing Impellers," International Journal of Chemical Engineering, Volume 2012

(2012), Article ID 106496. Downloaded from: http://www.hindawi.com/journals/ijce/2012/106496/

Garvin, John, "Understand the Thermal Design of Jacketed Vessels", Chemical Engineering Progress, Vol

95, No 6, June 1999, page 61.

Garvin, John, "Estimate Heat Transfer and Friction in Dimple Jackets", Chemical Engineering Progress,

Vol 97, No 4, April 2001, pages 73‐75.

Garvin, John, “Evaluate Flow and Heat Transfer in Agitated Jackets,” Chemical Engineering Progress,

August 2005, pages 39‐41.

Hemrajani, Ramesh R., “Mixing and Blending,” from the Kirk‐Othmer Encyclopedia of Chemical

Technology, Version 2, Wiley, published online 15 Apr 2005.

Hemrajani, Ramesh R., and Tatterson, Gary B., "Mechanically Stirred Vessels," Chapter 6 in Handbook of

Industrial Mixing, edited by Edward Paul, Victor Atiemo‐Obeng and Suzanne Kresta, John Wiley, 2004.

Lloyd, J.R., Moran, W.R., Natural convection adjacent to horizontal surfaces of various platforms,” ASME

Paper 74‐WA/HT‐66, 1974.

McAdams, W.H., Heat Transmission, 3rd Edition, McGraw‐Hill, New York, 1954.

Nienow, Alwin W., “Stirred Tank Reactors,” from Ullmann’s Encyclopedia of Industrial Chemistry, Wiley,

published online 15 Jan 2010.

TANKJKT

46

Penny, W.R., "Heat transfer correlations", in Handbook of Heat Exchanger Technology, Hemisphere

Publishing Corp., New York (1983).

Penny, W.R., Atiemo‐Obeng, V.A., “Heat Transfer,” Chapter 14 in Handbook of Industrial Mixing, edited

by Edward Paul, Victor Atiemo‐Obeng and Suzanne Kresta, John Wiley, 2004.

Poling, B.E., Prausnitz, J.M., O'Connell, J.P., Properties of Gases and Liquids, Fifth Edition, McGraw‐Hill,

2001.

Rieger, F., Ditl, P., Noval, V., “Vortex depth in mixed unbaffled vessels,” Chem Eng Sci, 34:397‐403

(1979).

Uhl, Vincent W., "Mechanically Aided Heat Transfer," Chapter 5 in Mixing: Theory and Practice, Vol 1,

edited by Vincent Uhl, Academic Press, 1966.

Welty, J.R., Wicks, C.E., Wilson, R.E., Rorrer, G.L., Fundamentals of Momentum, Heat and Mass Transfer

(5th Edition), John Wiley and Sons, 2007.

Zlokarnik, Marko, Stirring: Theory and Practice, Wiley‐VCH, Weinheim, Germany, 2001.

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