Previous Years GATE MCQ’s on Hydraulic Machines

Solved GATE Questions on Hydraulic Machines

Question 1. Match the following

 

(A) P-2, Q-1, R-7, S-6

(B) P-3, Q-1, R-5, S-7

(C) P-1, Q-3, R-1, S-5

(D) P-3, Q-4, R-7, S-6

GATE-ME-2003

Hint

Question 2. A centrifugal pump running at 500 rpm and its maximum efficiency is delivering a head of 30 m at flow rate of 60 litre per minutes. If the rpm is changed to 1000, then the head H in metres and flow rate Qin litresper minute at maximum efficiency are estimated to be

(A) H=60, Q=120

(B) H=120, Q=120

(C) H= 60, Q=4800

(D) H= 120, Q=30

GATE-ME-2003

Hint

Question 3. Match the following

 

 

(A)v P-3, Q-5, R-6, S-2

(B) P-3, Q-5, R-2, S-6

(C) P-3, Q-5, R-1, S-6

(D) P-4, Q-5, R-1, S-6

GATE-ME-2004

Hint

Question 4. At hydroelectric power site, available head and flow rate are 24.5 m and 10.1  respectively. If the turbine to be installed is required to run at 4.0 revolution per second (rps) with an overall efficiency 90%, then suitable type of turbine for the site is

(A) Francis

(B) Kaplan

(C) Pelton

(D) Propeller

GATE-ME-2004

Hint

Question 5. A centrifugal pump is required to pump water to an open water tank situated 4 km away from the location of the pump through a pipe diameter 0.2 m having Darcy friction factor of 0.01. The average speed of water in the pipe is 2 m/s. If it is to maintain a constant head of 5m in the tank, neglecting other minor losses, then absolute discharge pressure at the pump exit is

(A) 0.449 bar

(B) 5.503 bar

(C) 44.911 bar

(D) 55.203 bar

GATE-ME-2004

Hint

Question 6. A horizontal shaft centrifugal pump lifts water at 65. The suction nozzle is one meter below pump centerline. The pressure at this point is equal to 200 kPa gauge and velocityis 3 m/s. Steam tables show saturation pressure at 65 is 25 kPa, and specific volume of the saturated liquid is 0.0010  . The pump Net Positive Suction Head (NPSH) in meters is

(A) 24

(B)  26

(C) 28

(D) 30

GATE-ME-2006

Hint

Question 7. A large hydraulic turbine is to generate 300 kW at 1000 rpm under a head of 40 m. For initial testing , a 1:4 scale model of the turbine operates under a head of 10 m. The power generated by the model (in KW) will be

(A) 2.34

(B) 4.68

(C) 9.38

(D) 18.75

GATE-ME-2006

Hint

Question 8. In a pelton wherel, the bucket peripheral speed is 10 m/s, the water jet velocity is 25 m/s and volumetric flow rate of the jet is 0.1  . If the jet deflection angle is 120and the flow is ideal, the output developed is

(A) 7.5 kW

(B) 15.0 kW

(C) 22.5 kW

(D) 37.5 Kw

GATE-ME-2006

Hint

Question 9. Match the items in column I and Column II

 

(A)  P-2,          Q-3,       R-4,         S-1

(B)  P-2,          Q-3,       R-1,         S-4

(C) P-3,           Q-4,      R-1,          S-2

(D)  P-1,          Q-2,      R-3,          S-4

  GATE-ME-2007

Hint

Question 10. The inlet angle of runner blades of a Francis turbine is 90. The blades are so shaped that the tangential component of velocity at blade outlet is zero. The flow velocity remains constant throughout the blade passage and is equal to half of the blade velocity at runner inlet. The blade efficiency of the runner is

(A) 25 %

(B) 50 %

(C) 80 %

(D) 89 %

GATE-ME-2007

Hint

Question 11. Water having a density of 1000 , issues from a nozzle with a velocity of 10 m/s and the jet strikes a bucket mounted on a Pelton wheel. The wheel rotates at 10 rad/s. the mean diameter of the wheel is 1 m. The jet is split into two equal streams by the bucket, such hat each stream is deflected by 120, as shown in the figure. Friction in the bucket may be neglected. Magnitude of the torque exerted by the water on the wheel, per unit mass flow rate of the incoming jet, is

(A) 0 (N.m)/(kg/s)

(B) 1.25 (N.m)/(kg/s)

(C) 2.5  (N.m)/(kg/s

(D) 3.75 (N.m)/(kg/s)

GATE-ME-2008

Hint

Question 12. Consider steady, incompressible and irrotational flow through a reducer in a horizontal pipe where the diameter is reduced from 20 cm to 10 cm. The pressure in the 20 cm pipe just upstream of the reducer is 150 kPa. The fluid has a vapour pressure of 50 kPa and a specific weight of 5 . Neglecting frictional effects, the maximum discharge () that can pass through the reducer without causing cavitation is

(A) 0.05

(B) 0.16

(C) 0.27

(D) 0.38

GATE-ME-2009

Hint

Question 13. A hydraulic turbine develops 1000 kW power for a head of 40m. if the head id reduced to 20 m, the power developed (in kW) is

(A) 177

(B) 354

(C) 500

(D) 707

GATE-ME-2010

Hint

Question 14. The velocity triangles at the inlet and exit of the rotor of a turbomachine are shown. V denotes the absolute velocity of the fluid. W denotes the relative velocity of the fluid and U denotes the blade velocity. Subscripts 1 and 2 refer to the inlet and outlet respectively. If , the degree of reaction is

(A) 0

(B) 1

(C) 0.5

(D) 0.25

GATE-ME-2012

Hint

Question 15. In order to have maximum power from a pelton turbine, the bucket speed must be

(A) Equal to jet speed

(B) Equal to half of the jet speed

(C) Equal to twice of the jet speed

(D) Independent of the jet speed

GATE ME-2013

Hint

Answer Keys