Description : In centrifugal compressor terminology, vaneless space refers to the space between A. The inlet and blade inlet edge B. Blades in the impeller C. Diffuser exit and volute casing D. Impeller tip and diffuser inlet edge
Last Answer : ANSWER : D
Description : The blades of a centrifugal impeller are said to be curved forward, if the __________ of the motion of impeller blades. (A) Inlet tip of a blade curves in a direction opposite to that (B) Outlet tip ... Inlet tip of a blade is towards the direction (D) Outlet tip of a blade is towards the direction
Last Answer : (D) Outlet tip of a blade is towards the direction
Description : A centrifugal pump is called a turbine pump, if it is having a (A) Turbine type impeller (B) Vaned diffusion casing (C) Rotating vaned volute (D) None of these
Last Answer : (B) Vaned diffusion casing
Description : Design of the casing of centrifugal pump should be such as to minimise the (A) Back flow through impeller (B) Loss of kinetic head (C) Loss of static head (D) None of these
Last Answer : (B) Loss of kinetic head
Description : Which of the following is not the function of a volute casing provided in a centrifugal pump? (A) To reduce the head loss in discharge (B) To increase the pump efficiency (C) To collect liquid ... and to transmit it to the delivery pipe at constant velocity (D) To increase the pump discharge rate
Last Answer : Option D
Description : Pick up the correct statement from the following regarding radial flow centrifugal pumps: (A) These are provided with volute type or turbine type casings (B) In involute type of radial flow ... centrifugal pump, is always higher than that of volute type (D) All the above
Last Answer : (D) All the above
Description : Which is the correct relationship for a centrifugal pump? (Where, D = Impeller diameter, inches H = Head developed, ft of liquid pumped N = Speed of pump, rpm) (A) D = 1840 H0.5 /N (B) D = 1840 N/H0.5 (C) H = 1840 D0.5 /N (D) D = 1840 H/N
Last Answer : (A) D = 1840 H0.5 /N
Description : Which statement best describes the operating principle of a constant-speed propeller? a. As throttle setting is changed by the pilot, the prop governor causes pitch angle of the propeller blades to ... the pilot, the RPM of the engines remains constant as the pitch angle of the propeller changes
Last Answer : b. The propeller control regulates the engine RPM and in turn the propeller RPM
Description : The head developed by a centrifugal pump is largely determined by the (A) Power of the pump (B) Nature of the liquid being pumped (C) Angle of the vanes and the speed of the tip of the impeller (D) Vapour pressure of the liquid
Last Answer : (C) Angle of the vanes and the speed of the tip of the impeller
Description : Which one of the following statements is correct? A. Reciprocating compressors are used to supply large quantities of air at a lower pressure ratio B. Centrifugal compressors are used to supply ... . Centrifugal compressors cannot be run at high speed because of impeller, diffuser and casing.
Last Answer : ANSWER : B
Description : Volute type of casing is provided in a centrifugal pump to (A) Convert velocity head to pressure head (B) Convert pressure head to velocity head (C) Reduce the discharge fluctuation (D) Increase the discharge
Last Answer : (D) Increase the discharge
Description : Which of the following options will facilitate the achievement of a very high head (say 30 metres) in case of a centrifugal pump? (A) Increasing the impeller speed and the volute area (B) Increasing the number of vanes ... or more impellers in series on a single shaft (D) Either of (A), (B) or (C)
Last Answer : (C) Mounting of two or more impellers in series on a single shaft
Description : The capacity of a centrifugal pump Can be increased by increasing the (A) Impeller diameter or speed (B) Number of pumps and joining them in series (C) Number of pumps and joining them in parallel (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the __________ decreases. (A) ... the pump (C) Head of the liquid pumped (D) All (A), (B) and (C)
Description : With a constant diameter impeller of a centrifugal pump (A) Its capacity varies directly as the square of speed (B) Head varies as the square of speed (C) Horsepower input varies as the square of speed (D) Head varies as the speed
Last Answer : (B) Head varies as the square of speed
Description : Priming of a centrifugal pump is done to (A) Increase the mass flow rate of fluid (B) Develop effective pressure rise by the pump (C) Avoid chances of separation inside the impeller (D) None of these
Last Answer : (C) Avoid chances of separation inside the impeller
Description : Theoretical head developed by a centrifugal pump does not depend upon the __________ the impeller. (A) Radius of (B) Speed of (C) Fluid velocity leaving (D) None of these
Last Answer : (D) None of these
Description : In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the __________ efficiency. (A) Manometric (B) Mechanical (C) Volumetric (D) Overall
Last Answer : (A) Manometric
Description : Head developed by a centrifugal pump depends on its (A) Speed (B) Impeller diameter (C) Both (A) and (B) (D) Neither (A) nor (B)
Last Answer : C) Both (A) and (B)
Description : At a constant speed of the centrifugal pump, it’s __________ the impeller diameter. (A) Capacity varies directly with (B) Head varies as the square of (C) Horsepower varies as the cube of (D) All (A), (B) and (C)
Description : In case of a centrifugal pump, the theoretical head developed is dependent on the __________ the impeller. (A) Speed of (B) Diameter of (C) Fluid velocity leaving (D) All (A), (B) and (C)
Description : A mixed flow centrifugal pump (A) Employs such an impeller, through which the flow is a combination of radial & axial flow (B) Mixes the two fluids before pumping them (C) Pumps the two fluids separately and then mixes them (D) Employs impellers in both the radial & axial directions
Last Answer : (A) Employs such an impeller, through which the flow is a combination of radial & axial flow
Description : Erosion and pits formation on the impeller of a centrifugal pump may be due to (A) Cavitation (B) Low speed of impeller (C) Its operation with delivery valve closed for considerable time after starting the pump (D) Off centering of pump with motor
Last Answer : (A) Cavitation
Description : In case of a, centrifugal pump, the ratio h1/h2is termed as the __________ efficiency (where, h1 = actual measured head & h2 = head imparted to the fluid by impeller). (A) Mechanical (B) Overall (C) Volumetric (D) Impeller
Last Answer : A) Mechanical
Description : Good design of the casing of a centrifugal pump aims at minimising the (A) Cavitation (B) Frictional losses (C) Kinetic energy loss (D) Static head
Last Answer : Option C
Description : A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the power consumed now will be __________ hp. (A) 0.5 (B) 2 (C) 4 (D) 1
Last Answer : (A) 0.5
Description : The peripheral velocity at inlet of a centrifugal pump having inlet diameter of 25 cms and rotating at 950 rpm is __________ m/sec. (A) 1.8 (B) 12.4 (C) 186.2 (D) 736.4
Last Answer : (B) 12.4
Description : A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, then the new head will be __________ metres. (A) 2 (B) 4 (C) 8 (D) 5.5
Last Answer : (A) 2
Description : A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the new discharge will be __________ litres/minute. (A) 500 (B) 200 (C) 1000 (D) 750
Last Answer : (A) 500
Description : In case of unsteady fluid flow, conditions & flow pattern change with the passage of time at a position in a flow situation. Which of the following is an example of unsteady flow? (A) ... level is maintained (D) Low velocity flow of a highly viscous liquid through a hydraulically smooth pipe
Last Answer : (B) Water flow in the suction and discharge pipe of a reciprocating pump
Description : The efficiency of a centrifugal pump is maximum when its blades are : (A) straight (B) bent forward (C) bent backward (D) bent forward first and then backward
Last Answer : The efficiency of a centrifugal pump is maximum when its blades are : bent backward
Description : Noise produced by cooling fans (employed in air cooled heat exchangers or cooling tower) is mainly caused due to the turbulence created by blade passage through air. It can be reduced by use of a slower fan (A) With greater ... (B) Of increased diameter (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) & (B)
Description : For the production of very high vacuum, a __________ pump is normally used. (A) Diffusion (B) Centrifugal (C) Jet ejector (D) Piston
Last Answer : (A) Diffusion
Description : Following is not type of blades ? a) ‗L‘ type blade. c) Twisted blade b) ‗M‘ type blade. d) Straight blade
Last Answer : M‘ type blade.
Description : The following types of blades are used with the rotor in rotary tiller a. ‗L‘ type blade c) both A & B b. Twisted blade d) chisel plough
Last Answer : both A & B
Description : In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes (A) Less than atmospheric pressure (B) More than liquid vapor pressure (C) Less than liquid vapor pressure (D) More than atmospheric pressure
Last Answer : (C) Less than liquid vapor pressure
Description : 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
Last Answer : ANSWER : C
Description : harrow which consist of one or more blades attached to the beam Or frame, used for shallow working of the soil. A Spike tooth harrow B Acme harrow C Spring tooth harrow D Blade harrow
Last Answer : Blade harrow
Description : The isentropic enthalpy drop in moving blade is two-third of the isentropic enthalpy drop in fixed blades of a turbine. The degree of reaction will be (A) 0.4 (B) 0.56 (C) 0.67 (D) 1.67
Last Answer : (A) 0.4
Description : The pressure rise in the impeller of centrifugal compressor is achieved by A. the decrease in volume and diffusion action B. the centrifugal action and decrease in volume C. the centrifugal and diffusion action D. the centrifugal and push pull action
Description : The rotavator blade is generally operated at a) 180-320 rpm b) 450-1000 rpm c) 200 – 600 rpm d) None of these Ans. a
Last Answer : ans a
Description : The pump impeller and the turbine runner in a hydraulic torque converter (A) Have the same diameter (B) Have different diameters (C) Are directly coupled (D) None of these
Last Answer : (B) Have different diameters
Description : The most important factor, which determines the maximum height to which water can be lifted by a pump at standard temperature is the (A) Barometric pressure (B) Speed of the impeller (C) Diameter of the impeller (D) Both (B) and (C)
Last Answer : (A) Barometric pressure
Description : How can you determine the largest impeller that a pump can handle?
Last Answer : The motor amperage should be measured in the field with the pump discharge valve wide open. Subtract about 10% from the pumps maximum rated amperage. Then the maximum impeller size can be ... minus 10% A1 = Current operating amperage d2 = Maximum impeller diameter d1 = Current impeller diameter
Description : Height of liquid in agitation tank is normally maintained equal to the tank diameter. However, if the tank is too tall and a large liquid hold up is desired, then two or more impellers mounted on the same shaft may be used. The ... where, D = impeller diameter) (A) 0.5 D (B) D (C) 1.5 D (D) 2 D
Last Answer : (B) D
Description : The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost is P. Inlet pressure Q. Compressor rpm R. Delivery pressure S. Volumetric flow rate at inlet. (A) P, Q and R (B) P and R (C) R and S (D) P, Rand S
Last Answer : (A) P, Q and R
Description : If you hear a loud buzzing noise coming from a magnetic motor controller, you should ____________. A. assume that the motor is operating at a full load B. assume that the controller is operating normally C. ... of the problem D. feel the outside of the casing with your hand to see if it is hot
Last Answer : Answer: C
Description : A jet engine turbine blade is normally manufactured by (A) Forging (B) Shell moulding (C) Investment casting (D) Pressure die casting
Last Answer : (C) Investment casting
Description : Delivery of insufficient quantity of liquid by a pump may be caused by (A) Air leak in the inlet (B) Low rpm (C) Too high a lift (D) All (A), (B) and (C)
Description : Ultracentrifuges running at speeds upto 100000 rpm is normally used for the (A) Separation of isotopes based on their density or molecular weights difference (B) Concentration of rubber latex (C) Separation of cream from milk (D) Dewaxing of lubricating oil
Last Answer : (A) Separation of isotopes based on their density or molecular weights difference (B) Conc