Hydraulic Machines

Multiple Choice QuestionsUnit 1

1. The process by which water is released to the atmosphere by the plants is calleda)Evoparationb)Transpirationc)Gasificationd)transportation

2. The science which deals with the depletion and replenishment of water resources is a)Geologyb)zoologyc)hydrologyd)cryptology

3. --------- is the graph of the cumulative values of water quantity against timea)Hydro Graphb)Mass Curvec)Flow duration Curved)Power duration Curve

4. Hydrograph studies can be done in about ----- sq. Kilomenters of areas.a)5000b)6000c)7000d)8000

5. The factors affecting the runoff area)Rainfall Patternb)Character of catchment areac)Topographyd)All the above

6. The theoritical in KW available from falling water can be calculated with the formulaa)Pth = wQ/(1000H)b)Pth = w/(QH)c)Pth = wQH/1000d)Pth = H/(1000wQ)

7. One of the following is not a safety measure in hydroelectric power plant for its safe operationa)Penstockb)Surge Tanksc)Jet disperserd)Sand traps

8. The water discharge from the ----- is passed on to the tailrace through a separate pipeline.a)Jet Disperserb)Pressure regulatorc) Surge Tankd)Screen

9. In order to draw the ------- curve, the cumulative volume of water that can be stored month after month is neededa)Flow durationb)Power durationc)massd)all the above

10. The negative inclination of a mass curve would show that the amount of water flowing in the reservoir was ---------- than the loss due to evaporation and seepagea)lessb)morec)equald)con't be predicted

11. All the water that falls from atmosphere to earth surface is called asa)Hydrocycleb)Atmospheric cyclec)Nitro Cycled)Carbon cycle

12. Discharge graphs are known asa)Hydrographb)Flow duration curvec)Mass curved)all the above

13. The flow duration curve is drawn with the help of ----a)Hydrographb)mass curvec)power duration curved)All of the above

14. ---------curve is a convinient device to determine the storage requirements of watera)Mass curveb)Flow duration curvec)Power duration curved)None of the above

15. The area under the --------- curve gives the total quantity of run-off during that perioda)Flow duration curveb)Mass curvec)Power duration curved)None of the above

16. The shape of the --------- curve may change with the length of recorda)Flow duration curveb)Mass curvec)Power duration curved)None of the above

17. The highest point of the hydrograph when the rate of discharge is greatest refers to ------a)peak dischargeb)average dischargec)Overall discharged)None of the above

18. power duration curve is used to find -------a)Average yield power from the projectb)Average flow ratec)Total time period d)None of the above

19. The increase of -------- decreases the viscosity of liquida)Temperatureb)Pressurec)Volumed)Density

20. Bernoulli's theorem deals with---------------- a)Conservation of Energyb)Conservation of momentumc)Conservation of massd)Coservation of water

Unit 21. Impact of jet is the force exerted due to

a)Change in momentum of the mass coming out of jetb)Change in K.E of jet coming out of jetc)Inertial motion of the mass coming out of jetd)Weight of mass coming out of jet

2. The efficiency of a jet of water having a velocity V striking a series of vertical plates moving with a velocity U is maximum whena)U = 2Vb)U = V/2c)U = 3V/2d)U= 4V/3

3. The force acting by the jet of liquid on a fixed vertical plate is given bya)F = aVb)F = aV2/2c)F = aV2d)F = a/V

4. the equation used for finding the force exerted by the jet on a plate is a)Continuity Equationb)Bernoulli's Equationc)Euler's Equationd)Impulse Momentum Equation

5. According to Euler momentum equation for the flow of jet through a moving blade. The work done per kg is given bya)U(VW1+VW2)b)U(VW1+VW2)/gc)U(VW1+VW2)Vr1d)(VW1+VW2)/gU

6. A jet of water with a velocity of V strikes a flat plate moving towards the jet with a velocity U. Then the force acting on the plate is given bya)F = a(V-U)2b)F = a(V+U)2c)F = a(V+U)2/2d)F = a(V+U)2/4

7. When the jet of liquid strikes to a fixed plate inclined at angle with the horizontal, the normal force acting on the plate is given by a)Fn=aV2sin2/2b) Fn=aV2sin2c) Fn=aV2sind) Fn=aV2cos

8. The force exerted by a jet of water on a stationary inclined plate in the direction of jet is given by a) Fx=aV2b) Fx=aV2(1+sin)c)Fx=aV2(1+cos)d)Fx=aV2sin2

9. The force exerted by a jet of water having velocity V on a curved plate moving with a velocity U is given by a) Fx=a(V-U)2b) Fx=a(V-U)2sin2c)Fx=a(V-U)2(1+sin)d)Fx=a(V-U)2(1+cos)

10. The force exerted by a jet of water having a velocity V on a series of vertical plates moving with a velocity U is given bya)Fx = a(V-U)b)Fx= aV2c)Fx = aVUd)None

11. In the case of a stationary vertical plate, the jet after striking the plate will get deflected through.................a)900b)450c)600d)1350

12. The force exerted by the jet on a plate which may be stationary or moving is -----a)Impact of jetb)Jet momentc)Jet energyd)Jet Velocity

13. the ration between the out put and input of the jet is called ------------- of the jeta)Jet efficiencyb)Jet powerc)Jet capacityd)Jet speed

14. For a given initial velocity of the jet, the vane efficiency is maximum , when the velocity of the jet at vane outlet -------------a)2 times to initial velocityb)Equal to initial velocityc)Half of initial velocityd)None of the above

15. When the jet strikes a moving curved plate tangentially, the loss of energy due to impact of the jet will --------------a)Zerob)100%c)50%d)25%

16. The force exerted by a jet of water on a ------------ no of moving plate is not practically feasible.a)Singleb)Two c)Manyd)None of the above

17. For a ---------------- vane, the radius of the vane at inlet and outlet is different.a)Radial curved vanesb)Tangential curved Vanec)Normal Vane

d)None of the above18. The tangentail velocities of the radial vane at the inlet and outlet is ---------------

a)Sameb)Not equalc)2 timesd)None of the above

19. For maximum efficiency of a radial curved vane, the vane angle at outlet should be ----------a)900b)450c)600d)00

20. Maximum efficiency of a series of vertical plate is ------------------a)50%b)75%c)25%d)100%

Unit -31. Kaplan turbine is:

(a) A high head mixed flow turbine (c) An outward flow reaction turbine (b) A low head axial flow turbine (d) An impulse inward flow turbine

2. The specific speed of an impulse hydraulic turbine will be greater than the specific speed of a reaction type hydraulic turbine. (a) True (b) False (c) Cant say (d) None

3. Specific speed of a Kaplan turbine ranges between (a) 30 and 60 (b) 60 and 300 (c) 300 and 600 (d) 600 and 1000

4. In the case of------------------- all the potential energy is converted to kinetic energy in the nozzles. a)Reaction Turbineb)Impulse Turbinec)Tangentail Turbined)Axial flow Turbine

5. In----------the available potential energy is progressively converted in the turbines rotors and the reaction of the accelerating water causes the turning of the wheel. a)Reaction Turbineb)Impulse Turbinec)Tangentail Turbined)Axial flow Turbine

6. Available potential energy is high and the flow available is comparatively low which suitable type of turbine for thisa)Reaction Turbine

b)Impulse Turbinec)Con't say

7. Which of the following is example for Impulse Turbinea)Pelton wheelb)Francis wheelc)Kaplan wheeld)None of the above

8. Which of the following is example for Reaction Turbinea)Pelton wheelb)Jonval wheelc)Kaplan wheeld)None of the above

9. Which of the following is Tangential flow turbinea)Pelton wheelb)Jonval wheelc)Kaplan wheeld)None of the above

10. Which of the following is Axial flow turbinea)Pelton wheelb)Jonval wheelc)Kaplan wheeld)None of the above

11. Pelton wheel turbine is example fora)High speed, Low headb)High head, low speed c)High head, High speedd)None of the above

12. Francis turbine is example fora)High speed, Low headb)High head, low speed c)High head, High speedd)Medium head, Medium Speed

13. Kaplan turbine is example fora)High speed, Low headb)High head, low speed c)High head, High speedd)None of the above

14. The water flow through runner is parallel to the direction of runner axis then such turbine isa)Radial flowb)Tangential flowc)Mixed flowd)Axial flow

15. The water flow through runner is radial to the direction of runner axis then such turbine isa)Radial flowb)Tangential flowc)Mixed flowd)Axial flow

16. The water flow through runner is radial direction and leaves parallel to the direction of runner axis then such turbine isa)Radial flowb)Tangential flowc)Mixed flow

d)Axial flow

17. What should be the ratio of blade speed of jet speed for the maximum efficiency of a Pelton wheel? a)1/4b)1/2c)3/4d)1

18. If is the blade angle at the outlet, then the maximum hydraulic efficiency of an ideal impulse turbine is:a)(1+cos )/2b)(1-cos )/2c)(1-sin )/2d)(1+sin )/2

19. The maximum efficiency in the case of Pelton wheel is (angle of deflection of the jet = 180 ) a)(1-cos )/2b)(1+cos )/2c)cos /2d)(1+cos )/4

20. Which of the following advantages is/are possessed by a Kaplan turbine over a Francis turbine? 1. Low frictional losses. 2. Part load efficiency is considerably high. 3. More compact and smaller in size. Select the correct answer using the codes given below (a) Only 1 (b) Only 1 and 2 (c) Only 2 and 3 (d) 1, 2 and 3

Unit - 4

1. Consider the following statements pertaining to specific speed of turbo machines:

1. Specific speed varies with shape of the runner and other parts of the machine. 2. Machines with higher specific speeds are limited to low heads. 3. Specific speed is dimensionless and is independent of variation of type of fluid used. Which of the statements given above are correct? (a) 1, 2 and 3 (b) 1 and 2 only (c) 2 and 3 only (d) 1 and 3 only

2. The specific speed (Ns) of a water turbine is expressed by which one of the following equations?

3. The specific speed of a hydraulic turbine depends upon (a) speed and power developed (c) speed and head of water (b) discharge and power developed

(d) speed, power developed and head of water

4. If the number of jets in a Pelton turbine is n, then the specific speed is: (a) n2 (b) n (c) n1/ 2 (d) Independent of n

5. The specific speed of a turbine is defined as the speed of a member of the same homologous series of a such a size that it (a) Delivers unit discharge at unit head. (b) Delivers unit discharge at unit power. (c) Delivers unit power at unit discharge. (d) Produces unit power under a unit head.

6. Which one of the following is the correct statement? Specific speed of a fluid machine (a) Refers to the speed of a machine of unit dimensions. (b) Is a type-number representative of its performance? (c) Is specific to the particular machine. (d) Depends only upon the head under which the machine operates.

7. Consider the following turbines/wheels 1. Francis turbine 2. Pelton wheel with two or more jets 3. Pelton wheel with a single jet 4. Kaplan turbine The correct sequence of these turbines/wheels in increasing order of their specific speeds is: (a) 2, 3, 1, 4 (b) 3, 2, 1, 4 (c) 2, 3, 4, 1 (d) 3, 2, 4, 1

8. Which one of the following statements is not correct in respect of hydraulic turbines? (a) (Speed) is proportional to (1/Diameter) (b) (Power) is proportional to (Speed)3 (c) (Power) is proportional to (Head)3/2 (d) (Speed) is proportional to (Head)1/2

9. In fluid machinery, the relationship between saturation temperature and pressure decides the process of (a) Flow separation (b) Turbulent mixing (c) Cavitation (d) Water hammer

10. Chances of occurrence of cavitation are high if the (a) Local pressure becomes very high (b) Local temperature becomes low (c) Thoma cavitation parameter exceeds a certain limit (d) Local pressure falls below the vapour pressure

11. ------------- in a pipe line is used to releive the pressure due to water hammera)Surge Tankb)Penstockc)Nozzled)None of the above

12. The power which appears in the expression for the specific speed is -------a)Specific powerb)Unit powerc)Direct powerd)None of the above

13. When the specific speed of a turbine lies between 300 -850 then the type of turbine is ---a)Kaplan b)peltonc)Francisd)None of the above

14. ------- speed of a pelton wheel means no load speed with no governer mechanism.a)Unit speedb)Specific Speed c)load speedd)None of the above

15. ---------- are the quantities which are obtained when the head on the turbine is unitya)Unit quanitiesb)Specific Quantitiesc)Total Quantitiesd)None of the above

16. Cavitation damage in the turbine runner occurs near the (a) Inlet on the concave side of the blades (b) Outlet on the concave side of the blades (c) Outlet on the convex side of the blades (d) Inlet on the convex side of the blades

17. Which one of the following turbines exhibits a nearly constant efficiency over a 60% to 140% of design speed? (a) Pelton turbine (b) Francis turbine (c) Deriaz turbine (d) Kaplan turbine

18. ---------- is the most efficient turbine for part load operation conditionsa)Kaplanb)Peltonc)Francisd)None of the above

19. The unit discharge of a turbine is given by the expression ------a)Q/H1/2=Cb)QH1/2=Cc)Q/H=Cd)Q/H2=C

20. High speed and low head indicate the turbine is ------- turbinea)Kaplanb)Peltonc)Francisd)None of the above

Unit 5

6. For centrifugal pump, the suction pipe has --------- diameter as compared to the discharge pipea) Smallerb) Largerc) Equald) Tapered

7. Cavitation in centrifugal pumps can be reduced by a)Reducing Dischargeb)Reducing suction headc)Increasing discharged)Increasing suction head

8. Manometric efficiency of a centrifugal pump is the ratio of manometric head to a)head imparted by impeller to liquidb)work supplied to shaftc)available head d)none

9. The ratio of power delivered to the fluid to the shaft input power is calleda)manometric efficiencyb)hydraulic efficiencyc)mechanical efficiencyd)over all efficiency

10. The specific speed of centrifugal pump is defined as the speed of a pump of such a size that a)delivers unit discharge under unit head b)requires unit power to develop unit headc)requires unit power to deliver unit discharged)Develops unit head whatever be the discharge

11. Series operation of centrifugal pump result ina)High speedb)Low speed c)High discharged)Low power consumption

12. Indicator diagram show for one complete revolution of Crane thea)Variation of kinetic head in the cylinderb)Variation of pressure head in the cylinderc)Variation of kinetic and pressure head in the cylinderd)Variation of potential head in the cylinder

13. Air vessel in reciprocating pump is useda)to obtain uniform flow rate b)to reduce suction headc)to increase delivery headd)All the above

14. During delivery stroke of a reciprocating pump, the separator may take placea)at the end of delivery strokeb)in the middle of delivery strokec)in the begining of delivery stroked)At the end of suction stroke

15. Negative slip is likely to occur of a reciprocating pump is a)Suction pipe is long and delivery pipe is shortb)Delivery pipe is long and suction pipe is shortc)Suction valve lift up before the end of delivery stroked)Leakage occur due to imperfect value seating's

16. When the speed of a centrifugal pump is doubled, the power required to drive the pump will: (a) Increase 8 times (b) Increase 4 times (c) Double (d) Remain the same

17. A centrifugal pump gives maximum efficiency when its blades are: (a) Bent forward (b) Bend backward (c) Straight (d) Wave shaped

18. Which one of the following types of impeller vanes are most commonly used in centrifugal type compressors? (a) Forward curved (b) Radial (c) Backward curved (d) Tangential

19. The vanes of a centrifugal pump are generally (a) Radial (b) Curved backward (c) Curved forward (d) Twisted

20. A centrifugal pump is started with its delivery valve kept (a) Fully open (b) Fully closed (c) Partially open (d) 50% open