design and static analysis of marine propeller · marine propeller hits the ice block in static...

INTERNATIONAL JOURNAL OF PROFESSIONAL ENGINEERING STUDIES Volume 10 /Issue 1 / JUN 2018

IJPRES

DESIGN AND STATIC ANALYSIS OF MARINE PROPELLER 1 REGALLA.LAKSHMI LAVANYA, 2 Dr.G.THRISEKHAR REDDY,

1 PG Scholar, Department of MECH, NALANDA INSTITUTE OF ENGINEERING ANDTECHNOLOGY,

Kantepudi (V), Sattenapalli (M), Guntur (D), A.P, India, Pin: 522438.

Mail Id: [email protected] 2Assistant Professor, Department of MECH, NALANDA INSTITUTE OF ENGINEERING ANDTECHNOLOGY,

Kantepudi (V), Sattenapalli (M), Guntur (D), A.P, India, Pin: 522438.

Mail Id: [email protected]

ABSTRACT

A propeller is a type of fan that transmits power by

converting rotational motion into thrust. A pressure

difference is produced between the forward and rear

surfaces of the airfoil-shaped blade, and a fluid (such

as air or water) is accelerated behind the blade.

Propeller dynamics can be modeled by both

Bernoulli's principle and Newton's third law. A

marine propeller is sometimes colloquially known as

a screw propeller or screw.

The present work is directed towards the study of

marine propeller working and its terminology, static

simulation and flow simulation of marine propeller

has been performed. In static analysis the von misses

stresses, resultant deformation; strain on blade area

has been displayed due to applied load when the

marine propeller hits the ice block In static analysis

the von misses stresses, resultant deformation; strain

on blade area has been displayed due to pressure

created by crash of propeller on ice berg when it is

under working condition by using three different

materials such as one generally used titanium alloy

and two advance composite materials. 60 degree and

70 degree angle marine propeller blade will be

modeled by using solid works software analysis will

perform by using ANSYS work bench.

INTRODUCTION

A propeller is a type of fan that transmits

power by converting rotational motion into thrust. A

pressure difference is produced between the forward

and rear surfaces of the airfoil-shaped blade, and a

fluid (such as air or water) is accelerated behind the

blade. Propeller dynamics can be modeled by both

Bernoulli's principle and Newton's third law. A

marine propeller is sometimes colloquially known as

a screw propeller or screw.

LITERATURE SURVEY

Design and Analysis of a Marine Propeller Palnati

Ramesh Babu PG scholar, Department of Mechanical

Engineering, SVR Engineering College, Nandyal,

JNTU Anathapur, Andhra Pradesh, India.

C.Chendrudu Associate Professor, Department of

Mechanical Engineering, SVR Engineering College,

Nandyal, JNTU Anathapur, Andhra Pradesh, India.

Work is directed towards the study of marine

propeller working and its terminology, simulation and

flow simulation of marine propeller has been

performed. The von misses stresses, resultant

deformation, strain and areas below factor of safety

has been displayed. The velocity and pressure with

which the propeller blade pushes the water has been

displayed in the results.

Prediction of Propeller Blade Stress Distribution

through FEA, kiam beng yeo, wai heng choong, wen

hen hau The Finite Element Analysis (FEA) of marine

propeller blade stress distribution due to Hydro

dynamic loading is presented and discussed. The

analysis provided a better insight to complex marine

GurmeetTypewritten Text166


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propeller shape and interaction with hydrodynamic

loadings. Stainless steel Wageningen B Series 3 blade

propeller with 250 mm diameter, EAR of 0.5 and P/D

ratio of 1.2 was adopted in the analysis. The propeller

was subjected to the rotational speed of 06000 rpm.

The pressure distribution demonstrated a positive

pressure region on the face section and a negative

region on the back section that produces the thrust

generation.

DESCRIPTION

Fig. 1: Rubber-Hub Propeller.

A. Blade Tip: The maximum reach of the blade from

the center of the propeller hub. It separates the leading

edge from the trailing edge.

B. Leading Edge: The part of the blade nearest the

boat, which first cuts through the water. It extends

from the hub to the tip.

C. Trailing Edge: The part of the blade farthest from

the boat. The edge from which the water leaves the

blade. It extends from the tip to the hub (near the

diffuser ring on through-hub exhaust propellers).

D. Cup: The small curve or lip on the trailing edge of

the blade, permitting the propeller to hold water better

and normally adding about 1/2" (12.7 mm) to 1" (25.4

mm) of pitch.

E. Blade Face: The side of the blade facing away

from the boat, known as the positive pressure side of

the blade.

F. Blade Back: The side of the blade facing the boat,

known as the negative pressure (or suction) side of the

blade.

G. Blade Root: The point where the blade attaches to

the hub

H. Inner Hub: This contains the Flo-Torq rubber hub

or Flo-Torq II Delrin® Hub System (Figures 2-2

above and 2-3). The forward end of the inner hub is

the metal surface which generally transmits the

propeller thrust through the forward thrust hub to the

propeller shaft and in turn, eventually to the boat.

I. Outer Hub: For through-hub exhaust propellers.

The exterior surface is in direct contact with the

water. The blades are attached to the exterior surface.

Its inner surface is in contact with the exhaust passage

and with the ribs which attach the outer hub to the

inner hub.

J. Ribs: For through-hub exhaust propellers. The

connections between the inner and outer hub, there

are usually three ribs, occasionally two, four, or five.

The ribs are usually either parallel to the propeller

shaft ("straight"), or parallel to the blades ("helical").

K. Shock-Absorbing Rubber Hub: Rubber molded

to an inner splined hub to protect the propeller drive

system from impact damage and to flex when shifting

the engine, to relieve the normal shift shock that

occurs between the gear and clutch mechanism -

generally used with low horsepower applications.

L. Diffuser Ring: Aids in reducing exhaust back

pressure and in preventing exhaust gas from feeding

back into propeller blades.

M. Exhaust Passage: For through-hub exhaust

propellers. The hollow area between the inner hub and

the outer hub through which engine exhaust gases are

discharged into the water. In some stern drive

installations using a through-transom exhaust system,

this passage carries air.



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N. Performance Vent System (PVS): PVS, is a

patented Mercury ventilation system, allows the

boater to custom tune the venting of the propeller

blades for maximum planning performance. On

acceleration, exhaust is drawn out of the vent hole

located behind each blade.

HOW PROPELLER WORKS

The "Push/Pull" Concept

To understand this concept, let us freeze a

propeller just at the point where one of the blades is

projecting directly out of the page. This is a right-

hand rotation propeller, whose projecting blade is

rotating from top to bottom and is moving from left to

right. As the blade in this discussion rotates or moves

downward, it pushes water down and back as is done

by your hand when swimming. At the same time,

water must rush in behind the blade to fill the space

left by the downward moving blade. These results in a

pressure differential between the two sides of the

blade: a positive pressure, or pushing effect, on the

underside and a negative pressure, or pulling effect,

on the top side. This action, of course, occurs on all

the blades around the full circle of rotation as the

engine rotates the propeller. So the propeller is both

pushing and being pulled through the water.

Fig. 2: Push and pull concept

Thrust/Momentum:

These pressures cause water to be drawn into

the propeller from in front and accelerated out the

back, just as a household fan pulls air in from behind

it and blows it out towards using the figure. The

marine propeller draws or pulls water in from its front

end through an imaginary cylinder a little larger than

the propeller diameter (Figure 4). The front end of the

propeller is the end that faces the boat. As the

propeller spins, water accelerates through it, creating

a jet stream of higher-velocity water behind the

propeller. This exiting water jet is smaller in diameter

than the actual diameter of the propeller.

This water jet action of pulling water in and

pushing it out at a higher velocity adds momentum to

the water. This change in momentum or acceleration

of the water results in a force which we can call

thrust.

Fig. 3: Airflow through fan is similar to water flow

through the propeller

Fig. 4: Thrust development

FAILURES IN PROPELLER BLADE

Cavitations:

Occurs when the pressure on the forward face of

the propeller blade becomes low enough that vapor

bubbles form and the water boils. As the vapor

bubbles pass over the blade face and move away from

the low pressure area, they collapse. The collapsing

of the vapor bubbles might seem trivial, but it is a

very violent event which can result in the pitting of



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the propeller surface. Cavitation is a major source of

propeller damage, vibration, noise, and loss of

performance. Cavitations can be caused by nicks in

the leading edge, bent blades, too much cup or simply

high boat speed. Ventilation or aeration

It occurs when surface air is drawn into the

propeller blades. When this happens, boat speed is

lost and engine RPM climbs rapidly. This can result

from a hull error, excessively tight cornering, a motor

that is mounted very high on the transom, or by over-

trimming the engine. Ventilation is most often

confused with Cavitations.

Surface-piercing

This propeller is a propeller that is positioned

so that when the boat is at full speed the waterline

passes through the propeller's hub. This is

accomplished by extending the drive shaft out through

the very bottom of the transom. When running

properly only one blade of a two bladed propeller is

actually in the water. The surface propeller is very

efficient at minimizing or eliminating cavitations by

replacing it with ventilation. With each stroke, the

propeller blade brings a bubble of air into what would

otherwise be the vacuum cavity region.

PROPELLER BLADE STATIC ANALYSIS

MODEL

Idealized propeller structure can be

simplified as a cantilever beam pivoted at the hub axis

with a single loading on the free end or uniformly

loaded along the beam. However, this ideal model

does not include the highly non-linear wake field or

external forces or moment such as the centrifugal

forces. As more parameters and flow characteristics

with different condition changes, more estimation

shall be necessary to improve the effectiveness of

theoretical analysis. As the propeller rotates about its

central hub axis, each blade suffers different inflow

field effect which causes various amplitudes of cyclic

resultant moments and forces. Carlton

(2007) suggested the general propeller blade stress

equation as:

Where, σT, σQ, σCBM, σCF and σP are the stress

components due to thrust, torque, centrifugal bending,

direct centrifugal force and out of plane stress

components, respectively.

Generally, the linear static solution through

displacement method in FEA can be described by

matrix equation as:

Where, [K] is the structural stiffness matrix, {U} is

the vector of unknown nodal displacement and {F} is

load vector ({Fa} and {Fc} of the applied and reaction

forces).

For {Fa}, it can be redefined to consider the loading

as the mechanical {Fm}, thermal {Fth} and

gravitational load {Fgr} and subsequently as:

Then, the mechanical load vector {Fm} is equal to the

sum of applied nodal forces and moments and

pressure elements as:

Where, {Fnd} is the applied nodal load vector {Fepr} is

the element of pressure load vector, e is the element

number and nel is the number of element. Meanwhile

the thermal and gravitational load vector can be

solved as:



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Where, {Fnt} is the nodal temperature load vector,

{Feth} is the element of thermal load vector, [Me] is

the element of mass matrix and {a} is the acceleration

vector.

Based on the above equations, the applied

load {Fa} for propeller blade stress distribution

prediction without involving thermal loading through

FEA method can be written as:

Where, the element of pressure load vector {Fepr} was

preceded from the propeller blade pressure

distribution study through CFD application.

Wageningen B-Series 3 blade propeller with P/D ratio

value of 1.2 was utilized to simulate the blade stress

distribution due to the hydrodynamic elements.

SOLID WORKS

Solid Works is mechanical design automation

software that takes advantage of the familiar

Microsoft Windows graphical user interface. It is an

easy-to-learn tool which makes it possible for

mechanical designers to quickly sketch ideas,

experiment with features and dimensions, and

produce models and detailed drawings.

A Solid Works model consists of parts, assemblies,

and drawings.

Typically, we begin with a sketch, create a base

feature, and then add more features to the

model. (One can also begin with an imported

surface or solid geometry).

We are free to refine our design by adding,

changing, or reordering features.

Associativity between parts, assemblies, and

drawings assures that changes made to one view

are automatically made to all other views.

We can generate drawings or assemblies at any

time in the design process.

The SolidWorks software lets us customize

functionality to suit our needs.

MODELING OF PROPELLER BLADE

Fig.5: Sketch of the hub

Fig.6: 60° Marine propeller

Fig.7: 70° Marine propeller

INTRODUCTION TO ANSYS 16.0

ANSYS 16.0 delivers innovative, dramatic simulation

technology advances in every major Physics

discipline, along with improvements in computing

speed and enhancements to enabling technologies

such as geometry handling, meshing and post-

processing. These advancements alone represent a

major step ahead on the path forward in Simulation

Driven Product Development. ANSYS 16.0 delivers



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innovative, dramatic simulation technology advances

in every major Physics discipline, along with

improvements in computing speed and enhancements

to enabling technologies such as geometry handling,

meshing and post-processing. These advancements

alone represent a major step ahead on the path

forward in Simulation Driven Product Development.

Fig. : Ansys simulation

STATIC ANALYSIS OF MARINE PROPELLER

Material used and properties Material Density

(kg/m3) Young

modulus (MPa)

Poisons ratio

Ti alloy 4620 9.6E10 0.36

Al metal matrix

2700 7.8E10 0.32

Al Si Mg alloy

2700 6.9E10 0.33

Fixed

Load 2000N

Mesh

FOR BLADE ANGLE 60° MATERIAL: Titanium Alloy

Stress

Deformation

Strain

Mass



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MATERIAL : Aluminium Metal Matix (KS1275) Stress :

Deformation :

Strain:

Mass:

MATERIAL:Aluminium Silicon Magnesium Alloy

Stress:

Deformation:

Strain:

Mass



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FOR BLADE ANGLE 70° Applying the same boundary conditions and load Mesh

MATERIAL:Titanium Alloy

Stress :

Deformation

Strain:

Mass:

MATERIAL:Aluminium Metal Matrix (KS1275)

Stress:

Deformation

Strain:



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Mass:

MATERIAL:Aluminium Silicon Magnesium Alloy

Stress:

Deformation

Strain:

Mass:

RESULTS

STATIC ANALYSIS 60° angle blade Materi

al Stress (MPa)

Deformation (mm)

Strain

Mass (kg)

Titanium alloy

229.33 5.45564 0.0023901

1.8447

Aluminium

Metal Matrix

230.09 6.9229 0.0029511

1.0781

Aluminium

Silicon Magnesium Alloy

229.87 7.7696 0.0033329

1.0781

70° angle blade Material Stres

s (MP

a)

Deformation (mm)

Strain

Mass (kg)

Titanium alloy

257.38

6.126 0.0026916

1.8441

Aluminium Metal Matrix

258.70

7.7795 0.0033306

1.0777



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Aluminium Silicon Magnesium Alloy

258.31

8.7287 0.0037591

1.077

CONCLUSION

Brief study about marine propeller and its

working is done in this project

By using solid works 2016 software marine

propeller of two different blade angles 60

degree, and 70 degree is done by using different

commands and features in solid work software.

Simulation , static analysis and flow analysis on

marine propeller is performed by using ANSYS

Static analysis is performed by selecting three

different materials i.e. one generally used

Titanium alloy and remaining two advance

composite materials alloy such as Aluminium

Metal matrix(KS1275) and Aluminium Silicon

Magnesiun Alloy for each blade angle(60deg &

70deg) on given load condition of 2000N.

Static analysis result values i.e.: stress, strain

and deformation because of applied load due to

impact of ice berg on blade is noted and

tabulated.

According to result table 60 degree angle blade

is showing least stress and deformation value

compare to 70 deg blade angles.

Compare to material Alloy steel is showing least

deformation compare to Titanium alloy but the

weight ratio of Alloy steel is more than

Titanium alloy and Titanium alloy showing least

max stress value compare to Alloy steel.

As compare to material all three materials

showing nearly same stress value on same

boundary condition and applied load.

But composite materials are showing less weight

ratio than Titanium alloy.

Due to least weight to strength ratio compare to

generally used Titanium alloy even which is

economically high cost we can prefer such

advance composite material too which has

properties like good strength ,least weight to

strength ratio , and economically less cost too.

Comparing two composite materials used in this project Aluminium silicon magnesium alloy

showing least stress compare to Aluminium

Metal Matrix (KS1275). REFERENCES

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Vibromneter ”Dept. of mechanics,university of

Ancona, pp43-54



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9) W.J.Colclough and J.G.Russel. “The Development Of A Composite Propeller Blade

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design and static analysis of marine propeller · marine propeller hits the ice block in static...

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