FLUID MECHANICS AND MACHINERY

2 MarksUNIT-IBASIC CONCEPTS AND PROPERTIES1. Define density or mass density.

Density of a fluid is defined as the ratio of the mass of a fluid to its volume.

Density, = mass/volume (Kg/m3)

water = 1000 Kg/m32. Define specific weight or weight density.

Specific weight or weight density of a fluid is defined as the ratio between the

weight of a fluid to its volume.

Specific weight, = weight/volume (N/m3)

= g

water = 9810 N/m33. Define specific volume.

Specific volume of a fluid is defined as the volume of fluid occupied by an unit wt

or unit mass of a fluid.

Specific volume = volume/ wt = 1/ = 1/g ----- for liquids

Specific volume = volume/ mass = 1/ ----- for gases4. Define dynamic viscosity.

Viscosity is defined as the property of fluid which offers resistance to the

movement of one layer of fluid over another adjacent layer of the fluid.

= ()*(du/dy)

dynamic viscosity or viscosity or coefficient of viscosity (N-s/m2)

1 N-s/m2 = 1 Pa-s = 10 Poise5. Define Kinematic viscosity.

It is defined as the ratio between the dynamic viscosity and density of fluid.

= / (m2/s)

1 m2/s = 10000 Stokes (or) 1 stoke = 10-4 m2/s6. Types of fluids.

Ideal fluid

Real fluid

Newtonian fluid

Non-Newtonian fluid Ideal Plastic fluid.7. Define Compressibility.

It is defined as the ratio of volumetric strain to compressive stress.

Compressibility, = (d Vol/ Vol) / dp (m2/N)

8. Define Surface Tension.

Surface tension is defined as the tensile force acting on the surface of the liquid

in contact with a gas or on the surface between two immiscible liquids such that the contact surface behaves like a membrane under tension.

Surface Tension, = Force/Length (N/m)

water = 0.0725 N/m; Mercury = 0.52 N/m

10. Define Capillarity.

Capillarity is defined as a phenomenon of rise or fall of a liquid surface in a small

tube relative to the adjacent general level of liquid when the tube is held vertically in the liquid. The rise of liquid surface is known as capillary rise while the fall of liquid surface is known as capillary depression.

Capillary Rise or fall, h = (4 cos) / gd

= 0 for glass tube and water; = 130 for glass tube and mercury

11. Define Vapour Pressure.

When vaporization takes place, the molecules start accumulating over the free liquid surface exerting pressure on the liquid surface. This pressure is known as

Vapour pressure of the liquid.12. Define Control Volume.

A control volume may be defined as an identified volume fixed in space. The boundaries around the control volume are referred to as control surfaces. An open

system is also referred to as a control volume.13. Define Pascals Law.It states The intensity of pressure at any point in a fluid at rest is same in all directions

14. What is Absolute pressure?

An absolute zero of pressure will occur when molecular momentum is zero. Such a situation can occur only when there is a perfect vacuum. The pressure measured with reference to absolute zero is called Absolute Pressure15. What is Gauge pressure?The pressure measured by a gauge(instrument) is relative to the atmospheric pressure is called gauge pressure. The instrument by which gauge pressure is measured is called pressure gauge in which the atmospheric pressure is marked as zero.

16. What is Vacuum Pressure?

The pressure of a fluid to be measured is less than the atmosphere pressure, is called vacuum pressure. It is also known as negative or suction pressure.

17. What is manometer?

The pressure of a fluid is measured at a point in a fluid by balancing the column of same liquid or the column of another liquid. According to this principle, the instrument used to measure the pressure of a liquid, are called manometer.

18. Define mechanical gauges?

The pressure of a fluid is measured at a point in a fluid by balancing the force of a spring or dead weight. According to this principle, the instrument used to measure the pressure of a fluid, are called Mechanical Gauges.

19. Define Adhesion.

The property of a liquid which enables the molecules of a liquid to adhere (stick) the molecule of a solid boundary surface with which it comes in contact is called adhesion.

20. Define Cohesion.

The property of a liquid by which the molecules of the same liquid attract each other or it is intermolecular attraction between the molecules of same liquid, is called cohesion.

UNIT-IIFLUID KINEMATICS AND SIMILARITIES

1. Define dimensional analysis.

Dimensional analysis is a mathematical technique which makes use of the study of dimensions as an aid to solution of several engineering problems. It plays an important role in research work.

2. Write the uses of dimension analysis?

It helps in testing the dimensional homogeneity of any equation of fluid motion.

It helps in deriving equations expressed in terms of non-dimensional parameters.

It helps in planning model tests and presenting experimental results in a systematic manner.

3. List the primary and derived quantities.

Primary or Fundamental quantities: The various physical quantities used to describe a given phenomenon can be described by a set of quantities which are independent of each other. These quantities are known as fundamental quantities or primary quantities. Mass (M), Length (L), Time (T) and Temperature () are the fundamental quantities.

Secondary or Derived quantities: All other quantities such as area, volume, velocity, acceleration, energy, power, etc are termed as derived quantities or secondary quantities because they can be expressed by primary quantities.

4. Write the dimensions for the followings.

Dynamic viscosity () ML-1T-2

Force (F) - MLT-2 Mass density () -ML-3Power (P) -ML2T-35. Define dimensional homogeneity.

An equation is said to be dimensionally homogeneous if the dimensions of the terms on its LHS are same as the dimensions of the terms on its RHS.

6. Mention the methods available for dimensional analysis.

Rayleigh method

Buckinghum method

7. State Buckinghams theorem.

It states that if there are n variables (both independent & dependent variables) in a physical phenomenon and if these variables contain m functional dimensions and are related by a dimensionally homogeneous equation, then the variables are arranged into n-m dimensionless terms. Each term is called term.

8. List the repeating variables used in Buckingham theorem.

Geometrical Properties l, d, H, h, etc, Flow Properties v, a, g, , Q, etc, Fluid Properties , , , etc.

9. Define model and prototype.

The small scale replica of an actual structure or the machine is known as its Model, while the actual structure or machine is called as its Prototype. Mostly models are much smaller than the corresponding prototype.10. List the types of fluid flow.

Steady and unsteady flow Uniform and non-uniform flow Laminar and Turbulent flow

Compressible and incompressible flow

Rotational and ir-rotational flow

One, Two and Three dimensional flow11. Define Steady and Unsteady flow.

Steady flow

Fluid flow is said to be steady if at any point in the flowing fluid various characteristics such as velocity, density, pressure, etc do not change with time.

V/t = 0p/t = 0/t = 0

Unsteady flow

Fluid flow is said to be unsteady if at any point flowing fluid any one or all characteristics which describe the behavior of the fluid in motion change with time.

V/t 0p/t 0/t 0

12. Define Uniform and Non-uniform flow.

Uniform flow

When the velocity of flow of fluid does not change both in direction and magnitude from point to point in the flowing fluid for any given instant of time, the flow is said to be uniform.

V/s = 0p/s = 0/s = 0

Non-uniform flow

If the velocity of flow of fluid changes from point to point in the flowing fluid at any instant, the flow is said to be non-uniform flow.

V/s 0p/s 0/s 0

13. Compare Laminar and Turbulent flow.

Laminar flow

A flow is said to be laminar if Reynolds number is less than 2000 for pipe flow. Laminar flow is possible only at low velocities and high viscous fluids. In laminar

type of flow, fluid particles move in laminas or layers gliding smoothly over the

adjacent layer.Turbulent flow

In Turbulent flow, the flow is possible at both velocities and low viscous fluid. The flow is said to be turbulent if Reynolds number is greater than 4000 for pipe flow. In Turbulent type of flow fluid, particles move in a zig zag manner.

14. Define Compressible and incompressible flow

Compressible flow

The compressible flow is that type of flow in which the density of the fluid changes from point to point i.e. the density is not constant for the fluid. It is expressed in kg/sec.

constant

Incompressible flow

The incompressible flow is that type of flow in which the density is constant for the fluid flow. Liquids are generally incompressible. It is expressed in m3/s.

= constant

15. Define Rotational and Ir-rotational flow.

Rotational flow

Rotational flow is that type of flow in which the fluid particles while flowing along stream lines and also rotate about their own axis.

Ir-rotational flow

If the fluid particles are flowing along stream lines and do not rotate about their own axis that type of flow is called as ir-rotational flow

16. Define One, Two and Three dimensional flow.

One dimensional flow

The flow parameter such as velocity is a function of time and one spaceco- ordinate only.

u = f (x),v = 0&w = 0.

Two dimensional flow

The velocity is a function of time and two rectangular space co-ordinates.

u = f1(x,y),v = f2(x,y)&w =0.

Three dimensional flow

The velocity is a function of time and three mutually perpendicular directions.

u = f1(x,y,z),v = f2(x,y,z)&w = f3(x,y,z).17. Give an expression for loss of head due to sudden enlargement of the pipe.he = (V1-V2)2 /2g

Where he = Loss of head due to sudden enlargement of pipe.

V1 = Velocity of flow at section 1-1

V2 = Velocity of flow at section 2-218. Give an expression for loss of head due to sudden contraction.

hc =0.5 V2/2g

Where hc = Loss of head due to sudden contraction.

V = Velocity at outlet of pipe.19. Give an expression for loss of head at the entrance of the pipe.hi =0.5V2/2g

Where hi = Loss of head at entrance of pipe.

V = Velocity of liquid at inlet and outlet of the pipe.20. State Bernoullis theorem.

It states in a steady, ideal flow of an incompressible fluid, the total energy at any point of the fluid is constant. The total energy consists of pressure energy, kinetic energy and potential energy or datum energy. These energies per unit weight of the fluid are:

Pressure energy

Kinetic energy

Datum energy

Thus mathematically, Bernoullis theorem is written as

ConstantUNIT III

INCOMPRESSIBLE FLUID FLOW1. Mention the general characteristics of laminar flow.

There is a shear stress between fluid layers

No slip at the boundary

The flow is rotational

There is a continuous dissipation of energy due to viscous shear2. What is Hagen poiseuilles formula?

(P1-P2) / g = hf = 32 UL / gD2The expression is known as Hagen poiseuille formula.

Where P1-P2 / g = Loss of pressure head U = Average velocity

= Coefficient of viscosity D = Diameter of pipe

L = Length of pipe3. What are the factors influencing the frictional loss in pipe flow?

Frictional resistance for the turbulent flow is

i. Proportional to vn where v varies from 1.5 to 2.0ii. Proportional to the density of fluid.

iii. Proportional to the area of surface in contact.

iv. Independent of pressure.

v. Depend on the nature of the surface in contact.4. What is the expression for head loss due to friction in Darcy formula?

hf = 4fLV2 / 2gD

Where f = Coefficient of friction in pipe L = Length of the pipe

D = Diameter of pipe V = velocity of the fluid5. What do you understand by the terms (a) major energy losses, (b) minor energy losses?

(a) Major energy losses: -

This loss due to friction and it is calculated by Darcy weis bach formula and

chezys formula .

(b) Minor energy losses:-

This is due to

Sudden expansion in pipe. Sudden contraction in pipe. Bend in pipe.

Due to obstruction in pipe6. Define the terms a) Hydraulic gradient line [HGL], b) Total Energy line [TEL]

a) Hydraulic gradient line:-

Hydraulic gradient line is defined as the line which gives the sum of pressure head

and datum head of a flowing fluid in a pipe with respect the reference line .

b) Total energy line:-

Total energy line is defined as the line which gives the sum of pressure head, datum head and kinetic head of a flowing fluid in a pipe with respect to some

reference line.7. What is sypon? Where it is used?Sypon is along bend pipe which is used to transfer liquid from a reservoir at a

higher elevation to another reservoir at a lower level .

Uses of sypon : -

1. To carry water from one reservoir to another reservoir separated by a hill ridge.

2. To empty a channel not provided with any outlet sluice.8. What are the basic educations to solve the problems in flow through branched pipes?

i. Continuity equation.

ii. Bernoullis formula.

iii. Darcy weisbach equation.9. What is Dupuits equation?

L1/d15+L2/d25+L3/d35= L / d5Where

L1, d1 = Length and diameter of the pipe 1

L2, d2 = Length and diameter of the pipe 2

L3, d3 = Length and diameter of the pipe 310. Mention the range of Reynolds number for laminar and turbulent flow in a pipe.

If the Reynold,s number is less than 2000, the flow is laminar. But if theReynolds number is greater than 4000, the flow is turbulent flow.

11. What does Haigen-Poiseulle equation refer to?

The equation refers to the value of loss of head in a pipe of length L due to viscosity in a laminar flow.12. Give the formula for velocity distribution for flow through circular pipe.

The formula for velocity distribution is given as

u = - ( ) (p/x) (R2-r2)

Where R = Radius of the pipe, r = Radius of the fluid element13. Give the equation for average velocity for flow through circular pipe.The equation for average velocity is given as

= - (1/8) (p/x) R2Where R = Radius of the pipe

14. Write the relation between Umax and ?

Umax / = {- ( ) (p/x) R2} / {- (p/x) R2} Umax / = 2

15. Give the expression for the coefficient of friction in viscous flow?

Coefficient of friction between pipe and fluid in viscous flow f =16/ Re

Where, f = Re = Reynolds number

16. What are the factors to be determined when viscous fluid flows through the circular pipe?

The factors to be determined are:

Velocity distribution across the section.

Ratio of maximum velocity to the average velocity. Shear stress distribution.

Drop of pressure for a given length.17. Define kinetic energy correction factor.Kinetic energy factor is defined as the ratio of the kinetic energy of the flow per sec based on actual velocity across a section to the kinetic energy of the flow per sec based on average velocity across the same section. It is denoted by ().

K. E factor () = K.E per sec based on actual velocity / K.E per sec based on

Average velocity

18. Define momentum correction factor ().It is defined as the ratio of momentum of the flow per sec based on actual velocity to the momentum of the flow per sec based on average velocity across the section.= (Momentum per sec based on actual velocity)/ (Momentum Per sec based on average velocity)19. Define Boundary layer.

When a real fluid flow passed a solid boundary, fluid layer is adhered to the solid boundary. Due to adhesion fluid undergoes retardation thereby developing a small region in the immediate vicinity of the boundary. This region is known as boundary layer.

20. What is mean by boundary layer growth?

At subsequent points downstream of the leading edge, the boundary layer region increases because the retarded fluid is further retarded. This is referred as growth of boundary layer.

21. Classification of boundary layer.

(i) Laminar boundary layer, (ii) Transition zone, (iii) Turbulent boundary layer.

22. Define laminar boundary layer.

Near the leading edge of the surface of the plate the thickness of boundary layer is small and flow is laminar. This layer of fluid is said to be laminar boundary layer.

The length of the plate from the leading edge, upto which laminar boundary layer exists is called as laminar zone. In this zone the velocity profile is parabolic.

23. Define transition zone.

After laminar zone, the laminar boundary layer becomes unstable and the fluid motion transformed to turbulent boundary layer. This short length over which the changes taking place is called as transition zone.

24. Define turbulent boundary.

Further downstream of transition zone, the boundary layer is turbulent and continuous to grow in thickness. This layer of boundary is called turbulent boundary layer.

25. Define Laminar sub Layer

In the turbulent boundary layer zone, adjacent to the solid surface of the plate the velocity variation is influenced by viscous effects. Due to very small thickness, the velocity distribution is almost linear. This region is known as laminar sub layer.26. Define Boundary layer Thickness.

It is defined as the distance from the solid boundary measured in y-direction to the point, where the velocity of fluid is approximately equal to 0.99 times the free stream velocity (U) of the fluid. It is denoted by .

27. List the various types of boundary layer thickness.

Displacement thickness(*)

Momentum thickness()

Energy thickness(**)

28. Define displacement thickness.

The displacement thickness () is defined as the distance by which the boundary should be displaced to compensate for the reduction in flow rate on account of boundary layer formation.

* = [ 1 (u/U) ] dy

29. Define momentum thickness.

The momentum thickness () is defined as the distance by which the boundary should be displaced to compensate for the reduction in momentum of the flowing fluid on account of boundary layer formation.

= [ (u/U) (u/U)2 ] dy

30. Define energy thickness

The energy thickness (**) is defined as the distance by which the boundary should be displaced to compensate for the reduction in kinetic energy of the flowing fluid on account of boundary layer formation.

** = [ (u/U) (u/U)3 ] dy

31. What is meant by energy loss in a pipe?

When the fluid flows through a pipe, it loses some energy or head due to frictional resistance and other reasons. It is called energy loss. The losses are classified as; Major losses and Minor losses

32. Explain the major losses in a pipe.

The major energy losses in a pipe is mainly due to the frictional resistance caused by the shear force between the fluid particles and boundary walls of the pipe and also due to viscosity of the fluid.

33. Explain minor losses in a pipe.

The loss of energy or head due to change of velocity of the flowing fluid in magnitude or direction is called minor losses. It includes: sudden expansion of the pipe, sudden contraction of the pipe, bend in a pipe, pipe fittings and obstruction in the pipe, etc.UNIT IV

HYDRAULIC TURBINES

1. Define hydraulic machines.

Hydraulic Machines are defined as those machines which convert either hydraulic energy (energy possessed by water) into mechanical energy (which is further converted into electrical energy) or mechanical energy into hydraulic energy. The hydraulic machines, which convert the hydraulic energy into mechanical energy, are called turbines.2. Give example for a low head, medium head and high head turbine.

Low head turbine Kaplan turbine

Medium head turbine Modern Francis turbine

High head turbine Pelton wheel3. What is impulse turbine? Give example.

In impulse turbine all the energy converted into kinetic energy. From these the

turbine will develop high kinetic energy power. This turbine is called impulse

turbine. Example: Pelton turbine4. What is reaction turbine? Give example.

In a reaction turbine, the runner utilizes both potential and kinetic energies. Here portion of potential energy is converted into kinetic energy before entering into the turbine. Example: Francis and Kaplan turbine.5. What is axial flow turbine?

In axial flow turbine water flows parallel to the axis of the turbine shaft.

Example: Kaplan turbine

6. What is mixed flow turbine?

In mixed flow water enters the blades radially and comes out axially, parallel

to the turbine shaft. Example: Modern Francis turbine.7. What is the function of spear and nozzle?

The nozzle is used to convert whole hydraulic energy into kinetic energy. Thus the nozzle delivers high speed jet. To regulate the water flow through the nozzle and to obtain a good jet of water spear or nozzle is arranged.8. Define gross head and net or effective head.

Gross Head: The gross head is the difference between the water level at the reservoir and the level at the tailstock.

Effective Head: The head available at the inlet of the turbine.9. Define Specific Speed of the Turbine. It is defined as the speed of a turbine which is identical in shape, geometrical dimensions, blade angles, gate opening etc., with the actual turbine but of such a size that will develop unit power when working under unit head.

10. Define hydraulic efficiency.

It is defined as the ratio of the power given by water to the runner of a turbine to the power supplied by the water at the inlet of the turbine.

Power delivered to runner (runner power)

h = ------------------------------------------------------------

Power supplied at inlet (water power)Water power = QH = (1/2) mv2

11. Define mechanical efficiency.

It is defined as the ratio of power available at the turbine shaft to the power

developed by the turbine runner.Power available at the shaft (shaft power)

m = ------------------------------------------------------------

Power delivered to runner (runner power)

12. Define volumetric efficiency.

It is defined as the volume of water actually striking the buckets to the total water

supplied by the jet.13. Define overall efficiency.

It is defined as the ratio of power available at the turbine shaft to the power

available from the water jet.Power available at the shaft (shaft power)

o = ----------------------------------------------------------

Power supplied at inlet (water power)

o = h m v(or)o = h m14. Briefly classify the turbines.

Based on type of energy available at inlet

Impulse turbine (Pelton wheel)

Reaction turbine (Francis turbine, Kaplan turbine, Propeller turbine)

Based on head available at inlet

High head turbine [ > 250 m ] - (Pelton wheel)

Medium head turbine [ 60 to 250 m ] - (Francis turbine)

Low head turbine [ < 60 m ] (Kaplan turbine, Propeller turbine)

Based on specific speed

High specific speed turbine (Kaplan turbine, Propeller turbine) Medium specific speed turbine - (Francis turbine)

Low specific speed turbine - (Pelton wheel)

Based on direction of flow through runner Tangential flow turbine

Radial flow turbine Axial flow turbine

Mixed flow turbine15. What are the main parts of Pelton Wheel turbine?

Nozzle and flow regulating arrangement (Spear)

Runner and Buckets

Casing Breaking jet

16. What is mean by Draft Tube?

The draft tube is a pipe of gradually increasing area which connects the outlet of the runner to the tail race. One end of the draft tube is connected to the outlet of the runner while the other end is sub-merged below the level of water in the tail race17. Define Jet Ratio.

It is defined as the ratio of the pitch diameter (D) of the Pelton wheel to the diameter of the jet (d). It is denoted by m and is given as m = D/d 18. What is known as Eulers equation for turbo-machines?

The general expression for the work done per second on impeller is

Q[Vw1u1 + Vw2u2]19. Why do draft tubes have enlarging passage area in the direction of flow?

The pressure at the exit of the reaction turbine is generally less than atmospheric and this makes the water NOT to discharge directly to the tail race. By the introduction of draft tube, which has enlarged area in the direction of flow, the kinetic head reduces and pressure head increases. There by discharge of water to the tail race safely.20. Define Runaway speed of Turbine.

The max speed reached by the turbine after the removal of the external load is called runaway speed of turbine. The various rotating components of the turbine should be designed to remain safe at the runaway speed.UNIT-VHYDRAULIC PUMPS

1. What is roto dynamic pump?

When the increase in pressure is developed by rotating impeller or by action of centrifugal force then the pump is called as roto dynamic pump.

2. Define Centrifugal pump.

Hydraulic pump means it converts mechanical energy into hydraulic energy. If the mechanical energy is converted into pressure energy means of centrifugal force acting on the fluid, the hydraulic machine is called Centrifugal Pump.

3. Define Specific speed of a centrifugal pump.

The specific speed of a centrifugal pump is defined as the speed of a geometrically similar pump which would deliver 1 m3/s against a head of 1 m.

4. Define Manometric Efficiency?The ratio of the manometric head to the head imparted by the impeller to the water is known as manometric efficiency.

Manometric Head

g Hmmano = ------------------------------------------------- = -----------

Head imparted by impeller to water

Vw2u2Head imparted by impeller to water = Vw2u2/g5. Define mechanical efficiency of the Pump.

The ratio of the power available at the impeller to the power at the shaft of the centrifugal pump is known as mechanical efficiency.

Power at the impeller

mech= ---------------------------------

Shaft Power

Power at the impeller = workdone by impeller per sec = Q Vw2u26. Define Overall Efficiency.

The ratio of power output of the pump to the power input to the pump is called as overall efficiency.

Weight of water lifted x Hmo = ------------------------------------------

Shaft Power

7. Define Manometric Head.

The manometric head is defined as the head against which a centrifugal pump has to work.

Hm = head imparted by the impeller to the water loss of head

Hm = Vw2u2/g - loss of head

Hm = hs + hd + hfs + hfd + vd2/2g

8. Differentiate static head & manometric head.

Sl. No.Static HeadManometric Head

1The vertical head distance to liquid surface in sump to overhead tank.Total head that must be produced by pump to satisfy the external

requirements.

2Loss of head in the pump is not considered.The friction head loss & kinetic head are considered.

3H = Hs + HdHm = hs + hd + hfs + hfd + vd2/2g

9. What is mean by multi stage pump?

If more than one impeller is used in pump then such type is known as multistage pump.

Impellers in series Number of impellers are mounted on a common shaft. This increases the total head. Total head = n HmImpellers in parallel Impellers are mounted in separate shaft. This increases the

discharge. Total discharge = n Q10. Compare Centrifugal Pump & Reciprocating PumpSl. No.Centrifugal PumpReciprocating Pump

1Its discharging capacity is more.Its discharging capacity is low.

2It can be used for lifting highly viscous liquids.It can handle only pure water or less viscous liquids.

3Its maintenance cost is low.Its maintenance cost is high.

4It can be operated at very high speed.High speed may cause cavitations and separation.

11. What is mean by Priming of a Centrifugal Pump?

Priming of a Centrifugal Pump is defined as the operation in which the suction pipe, casing of the pump and a portion of the delivery pipe up to the delivery valve is completely filled up from outside source with the liquid to be raised by the pump before starting the pump. Thus the air from these parts of the pump is removed and these parts are filled with the liquid to be pumped. 12. Define Cavitation.

Cavitation is defined as the phenomenon of formation of vapour bubbles of a flowing liquid in a region where the pressure of the fluid falls below its vapour pressure and the sudden collapsing of these vapour bubbles in a region of higher pressure. 13. What is a reciprocating pump?

Reciprocating pump is a positive displacement pump. This means the liquid is first sucked into the cylinder and then displaced or pushed by the thrust of a piston.

14. What is single acting pump and double acting pump?

If the water is in contact with one side of the piston the pump then it is known as single acting reciprocating pump. For one complete revolution one suction stroke and one delivery stroke occurs.

If the water is in contact with both sides of the piston the pump then it is called double acting reciprocating pump. For one complete revolution two suction strokes and two delivery strokes occurs.

15. What is Discharge through a Reciprocating Pump?

For Single acting Reciprocating Pump: Discharge (QT) =ALN/60

For Double acting Reciprocating Pump: QT =2ALN/60

A=Area of the Cyclinder (m2), L=Length of Stroke (m), N=Speed of Crank (rpm)

16. What is the Workdone by Reciprocating Pump per sec?

For Single acting Reciprocating Pump: Workdone = gALN(hs+hd)/60

For Double acting Reciprocating Pump: Work done= 2gALN(hs+hd)/60

Where, =Density of Water (kg/m3), A=Area of the Cylinder (m2),

L= Stroke Length (m), N=Speed (rpm), hs, hd =Suction and Delivery head (m).

17. Define slip and % slip.

The difference between the theoretical discharge (QT) and actual discharge (Qact)

is known as slip of the pump.

Slip = QT - Qact% Slip = [(QT - Qact)/QT] x 100

If Qact is more than the QT then slip will be ive.

If Qact is lesser than QT then the slip will be +ive.

18. Define coefficient of discharge of reciprocating pump?

It is defined as the ratio of actual discharge to theoretical discharge of reciprocating pump. Cd=Qa/Qth. If Cd > 1 then ive slip occurs

If Cd < 1 then +ive slip occurs. 19. What is an air vessel?

An air vessel is a closed chamber containing compressed air in the top portion and liquid at the bottom of the chamber. At the base of the chamber there is an opening through which the liquid may flow into the vessel or out from the vessel. When the liquid enters the air vessel, the air gets compressed further and when the liquid flows out of the vessel, the air will expand into the chamber.

20. What is the purpose of an air vessel fitted in the pump?

To obtain a continuous supply of liquid at a uniform rate.

To save a considerable amount of work in overcoming the frictional resistance in the suction and delivery pipes, and

To run the pump at a high speed without separation. 21. Define indicator diagram?

The indicator diagram for a reciprocating pump is defined as the graph drawn between the pressure head in the cylinder and the distance traveled by the piston for one complete revolution of the crank Part BUNIT-I1. (i) If bulk modulus of water is 2.2 x10 Pa. What is the pressure required to reduce the volume of water by 6%?

(ii) Calculate the capillary effect of a glass tube of 4 mm diameter immersed in (a) water (b) mercury. The surface tension values of water and mercury in contact with air are 0.0075 kg/m and 0.05 kg/m respectively. The contact angle of water and mercury may be assumed as 30 and 40 respectively.

2. A 400 mm diameter shaft is rotating at 200 rpm in a bearing length 120mm. If the thickness of oil film is 1.5 mm and the dynamic viscosity of oil is 0.7 Ns/m2, determine (i) torque required to overcome the friction in bearing (ii) power utilized in overcoming viscous resistance. Assume linear velocity profile.

3. (i) State and derive the Newtons law viscosity.

(ii) Two square flat plates with side of 60cm are placed 12.55 mm apart. The lower plate is stationary and the upper plate requires a force of 100 N to keep moving with a velocity 2.5 m/s. Oil of specific gravity 0.95 is filled in between the plates. Determine the dynamic viscosity and kinematic viscosity of oil.

4. (i) Derive an expression for capillary rise.

(ii) An increase in pressure of a liquid from 7.5 MPa to 15 MPa resulting in 0.2% decrease in its volume. Determine the compressibility.

5. (i) Determine the mass density if 3 tonnes oil occupies a volume of 4 m3 .

(ii) A certain liquid occupying a volume of 1.6m3, weighs 12.8 KN. What is the specific weight of the liquid?

(iii) The shear stress at a point is 0.6MPa, where velocity gradient is 1.5 per second. If the kinematic viscosity of flowing fluid is 4.65 stokes, determine the relative density of the liquid.

6. If the equation of velocity profile over a plate is given by u = 2y y2, in which u is the velocity in m/s at a distance y measured I m above the plate. What is the velocity gradient at the boundary and at 7.5 cm and 15 cm from it? Also calculate the stress at these points, if the absolute viscosity id 8.6 poise.

7. Calculate the gauge pressure and absolute pressure within (a) a droplet of water of 0.4cm diameter and (b) a jet of water 0.4 cm diameter. Assume the surface tension of water as 0.073 N/m and atmospheric pressure as 101300 N/m2.

8. Assuming the bulk modulus of elasticity of water is 2.07 x106 kN/m2 at standard atmospheric conditions. determine the increase of pressure necessary to produce (a) 1% reduction in the volume at the same temperature and (b) 1% reduction in the volume of air undergoing an isentropic compression.

9. A simple manometer is used to measure oil (specific gravity 0.8) flow in a pipeline. Its right limb is open to the atmosphere and the left limb is connected to the pipe. The center of the pipe is 90cm below the level of mercury (specific gravity 13.6) in the right limb. If the difference of mercury level in the two limbs is 15cm, determine the absolute pressure of oil in the pipe in kN/m2.UNIT-II1. Derive the continuity equation for 3-D flow2. Obtain an expression Eulers equation. Deduce Bernoullis equation from it. What are the assumptions to be made?3. A 30 cm*15 cm venturimeter is provided in a vertical pipe line carrying oil of specific gravity of 0.9 floe being up wards .the difference elevation of the throat and entrance of the venturimeter is 25 cm. Calculate 1) the discharge of oil and 2)the pressure difference between the throat and entrance section. Cd=0.98.4. (i) Does a velocity given by U=5x 3 i-15x2 y +tk represent possible fluid motion of an in compressible flow. (ii) The two component of velocity in an incompressible flow are given by u=x3 -y3 and v=z3 y3. Determine the third component assuming that the origin is a stagnation point.UNIT-III1. Linseed oil at 25C flow in a 25 mm diameter pipe.

(i) What is the maximum average velocity for which the flow may considered laminar.

(ii) What is the pressure drop in 50 m of pipe at that flow?

(iii) What is the wall shear stress?

Take specific gravity s=0.93 and =0.0331 kg/ms.2. Water is flowing through pipe of diameter 250 mm with a velocity of 3 m/s. Find the head lost due to friction for a length of 5.5 m, if the coefficient of Friction f is given by f = 0.03+0.08/re.3 where re is Reynolds number. Take f =0.01 stokes.3. Oil having viscosity 0.096 Ns/m2 and specific gravity of 1.59 flows through a horizontal pipe. Of diameter 50mm with a pressure drop of 6 kn/m2 per m length of pipe. Determine (i) the rate of flow in kg/sec (ii) the shear stress at the pipe wall and (iii) the power required for 100 m length of the pipe to maintain the flow.4. Two reservoirs whose water surface elevations differ by 40 m are connected by a pipe line 30 cm diameter and 3km long in order to increase the discharge, an additional pipe line 20cm in diameter and 1.5 km long is laid parallel from the midpoint of the first one up to the lower reservoir. What is the increase in discharge due to the newly laid pipe?

5. Drive Darcy Weischback equation for head loss due to friction in flow through pipe.

6. Derive the Hagen poiseulles equation for laminar flow through a pipe.

7. Air is flowing over a flat plate with a velocity of 10 m/s. the length of the plate is 1.5m and width is1m. the kinematic viscosity of air given as 0.15x10-4 m2/s, Find

(i) The boundary layer thickness at end of the plate

(ii) Shear stress at 20cm from the leading edge and

(iii) Drag force on one side of the plate

Take the velocity profile over a plate as u/U=sin (/2x-y/) and the density of air as 1.24 kg/m3.

8. The rate of flow of water through a horizontal pipe is 0.3 m3/s. The diameter of the pipe is suddenly enlarged from 25 cm to 50 cm. The Pressure Intensity in the smaller pipe is 14 N/cm2 .determine (i) losses of head due to enlargement (ii) pressure intensity in the larger pipe and (iii) power lost due to enlargement.

9. A belt conveyor consists of a flat belt 0.25m wide, which slides at a velocity of 4 m/s parallel to a surface separating by a 6 cm thick layer of oil viscosity 0.25Ns/m2. Determine (a) the pressure gradient required to cause no shear stress at the belt surface and (b) the average velocity and discharge of oil to maintain for the above.

10. (i) For a flow of viscous fluid flowing through a circular pipe under laminar flow conditions show that the velocity distribution is parabola. (ii) Also show that the average velocity is half the maximum velocity.UNIT-IV1. The internal and external diameters of an inward flow reaction turbine are 0.6m and 1m respectively. The width of the wheel at inlet and outlet is 12cm. The head on the turbine is 9m and hydraulic efficiency is 90% the vane angle at outlet is 20.

The discharge at a outlet is redial at a velocity of 2.7m/s. Find (i) the guide the blade angel (ii) the runner vane angle at inlet (iii) the speed of the turbine. (iv) The discharge of the turbine and (v) water power.

2. A double jet pelt on wheel operates under a head of 40m. And develops 735kw brake power when running at 450rpm. Make calculations for flow tare and the diameter of nozzle jet. Assume overall efficiency is 0.85 coefficient of velocity CV=0.98.

3. Draw the inlet and outlet velocity triangles for a pelton wheel and indicate the direction of various velocities. Obtain an expression for the work done per second by water on the runner of the pelt n wheel. Giving the relationship between the jet speed and bucket speed.

4. Pelton wheel turbine is required to develop 9000kw when working under a head of 300 m the impeller mar rotate at 500 rpm. Assuming a jet ratio of 10 and an overall efficiency of 85% calculate (i) quantity of water required (ii)Diameter of the wheel (iii) number of jets and (iv) number and size of the bucket vanes on the runner.

5. An outward reaction turbine has internal diameters of the runner as 0.5 m and 1.0 m respectively. The turbine is running at 250rpm and rate of flow of water through the turbine is 8m3/s. The width of the runner is constant at inlet and outlet and is equal to 30cm. the head of the turbine is10m and discharge at outlet is radial. Determine (i) vane angle at inlet and outlet and outlet (ii) velocity of flow at inlet and outlet.

6.Explain about the different heads and efficiencies of a hydraulic turbine.

7.Explain about the different characteristic curves of a turbine.

8. A Kaplan turbine, operating under a net head of 20 m develops 36775 kW power with an overall efficiency of 86%. The speed ratio is 2 and flow ratio is 0.6, the hub diameter of the wheel is 0.35 the outside of the wheel. Find the Diameter and speed of the turbine.

9. Derive the Eulers principle energy equation for fluid machines.

10. A turbine is to operate under a head of 25 mat 200 rpm the available discharge is 9m3/s. Assuming an efficiency of 90% determine, (i) its specific speed (ii) power generated (iii) performance under a head of 20 m and (iv)The type of turbine.UNIT-V1. A centrifugal pump runs at 1540 rpm and discharges 120 lit/s against a head of 25m. If the diameter of the impeller is25cm and its width is 8 cm, find the vane angle at the outer periphery. The manometric efficiency of the pump is 75%.

2. The internal and external diameters of a centrifugal pump are 20 cm and 40 cm respectively. The speed of pump is 1400 rpm. Assuming a constant velocity of flow 5m/s throughout, radial entry to impeller and the exit vane angle of 30. Find (i).the inlet vane angle and (ii).work done by the impeller.

3. With a neat sketch explain the working of a centrifugal pump. Define the various heads and efficiency associated with centrifugal pumps.

4. The cylinder bore diameter of a single acting reciprocating pump is 150 mm and its stroke length is 300mm. the pump runs at 50 rpm and lift water through a height of 25m. The delivery pipe is 22m long and 100m diameter. Find the theoretical discharge and the theoretical power required to run the pump. If actual discharge is 4.2 lit/s, find the % slip.

5. What is a reciprocating pump? Describe principle and working of a double acting reciprocating pump with a neat sketch?6.A centrifugal pump having outer diameter equal to 2 times the inner diameter and running at 1200 rpm works against a total head of 75mm.the velocity of flow through the impeller is constant and is equal to 3m/s. the vanes are set back at an angle of 30 at outlet. If the outer diameter of the impeller is 600 mm and width at outlet is 50mm. determine (i) Vane angle at outlet. (ii) Work done per second by Impeller. (iii) Manometric efficiency.

7. The rate of flow of water through a horizontal pipe is 0.3m3/s. The diameter of the pipe is suddenly enlarged from 25cm to 50cm. The pressure intensity in the smaller pipe is 14N/cm2.Determine (i) the loss of head due to sudden enlargement (ii) pressure intensity in the larger pipe and (iii) power loss due to enlargement.

8. A belt conveyor consist of a belt 0.25m wide which slides at a velocity of 4m/s parallel to a surface separating by a 6cm thick layer of oil viscosity 0.25 Ns/m2.Determine (a) the pressure radiant required to cause no shear stress at the belt surface and b) the average velocity and discharge of oil maintain for the above.

9. (i) For a flow of viscous fluid flowing through a circular pipe under laminar flow conditions show that the velocity distribution is parabola. (ii)Also the show that the average velocity is half of the maximum velocity_1246374482.unknown

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