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

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
by

1 Answer

Answer :

Option C
by

Related questions

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

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

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 from the periphery of the impeller and to transmit it to the delivery pipe at constant velocity (D) To increase the pump discharge rate

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

Volute of a centrifugal pump should be designed in a fashion, such that the (A) Kinetic head gets converted into static head (B) Moving stream gradually reduces velocity (C) Mean velocity remains constant (D) None of these

Description : Volute of a centrifugal pump should be designed in a fashion, such that the (A) Kinetic head gets converted into static head (B) Moving stream gradually reduces velocity (C) Mean velocity remains constant (D) None of these

Last Answer : (A) Kinetic head gets converted into static head

Cavitation occurs in a centrifugal pump when the suction pressure is (A) Less than the vapour pressure of the liquid at that temperature (B) Greater than the vapour pressure of the liquid at that temperature (C) Equal to the vapour pressure (D) Equal to the developed head

Description : Cavitation occurs in a centrifugal pump when the suction pressure is (A) Less than the vapour pressure of the liquid at that temperature (B) Greater than the vapour pressure of the liquid at that temperature (C) Equal to the vapour pressure (D) Equal to the developed head

Last Answer : (A) Less than the vapour pressure of the liquid at that temperature

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

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

An ideal nozzle design aims at (A) Minimising wall friction (B) Suppressing boundary layer separation (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : An ideal nozzle design aims at (A) Minimising wall friction (B) Suppressing boundary layer separation (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

What causes cavitation in centrifugal pump? (A) High suction pressure (B) Low barometric pressure(C) Low suction pressure(D) High suction velocity

Description : What causes cavitation in centrifugal pump? (A) High suction pressure (B) Low barometric pressure (C) Low suction pressure (D) High suction velocity

Last Answer : (C) Low suction pressure

Cavitation in a centrifugal pump can be avoided by keeping the (A) Inlet pressure high (B) Outlet pressure low (C) Inlet pressure low (D) Outlet pressure high

Description : Cavitation in a centrifugal pump can be avoided by keeping the (A) Inlet pressure high (B) Outlet pressure low (C) Inlet pressure low (D) Outlet pressure high

Last Answer : (A) Inlet pressure high

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

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

. A special type of liquid transporting device is the diffuser pump, in which __________ are minimised. (A) Bearing losses (B) Disk friction (C) Shock losses (D) Cavitation

Description : . A special type of liquid transporting device is the diffuser pump, in which __________ are minimised. (A) Bearing losses (B) Disk friction (C) Shock losses (D) Cavitation

Last Answer : (C) Shock losses

Centrifugal pump is normally classified on the basis of the (A) rpm (B) Type of casing (C) Impeller blade angle (D) Number of blades in impeller

Description : Centrifugal pump is normally classified on the basis of the (A) rpm (B) Type of casing (C) Impeller blade angle (D) Number of blades in impeller

Last Answer : (B) Type of casing

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

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

In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure __________ the vapor pressure of the liquid at the suction temperature. (A) Lower than (B) Higher than (C) Equal to (D) None of these

Description : In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure __________ the vapor pressure of the liquid at the suction temperature. (A) Lower than (B) Higher than (C) Equal to (D) None of these

Last Answer : (B) Higher than

Liquid delivery by centrifugal pump starts, only when the head developed by it is equal to the __________ head. (A) Manometric (B) Total (C) Static (D) Friction

Description : Liquid delivery by centrifugal pump starts, only when the head developed by it is equal to the __________ head. (A) Manometric (B) Total (C) Static (D) Friction

Last Answer : (A) Manometric

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, the impeller discharges into a gradually expanding spiral casing (C) The efficiency of turbine type of radial flow centrifugal pump, is always higher than that of volute type (D) All the above

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 

Conversion of dynamic velocity head into static pressure head in a centrifugal pump is the result of : (a) Increasing area of flow between adjacent vanes from inlet to outlet (b) Difference in pressure between suction and delivery ends (c) Radial thrust in pumps (d) Stuffing Box

Description : Conversion of dynamic velocity head into static pressure head in a centrifugal pump is the result of : (a) Increasing area of flow between adjacent vanes from inlet to outlet (b) Difference in pressure between suction and delivery ends (c) Radial thrust in pumps (d) Stuffing Box

Last Answer : (b) Difference in pressure between suction and delivery ends

State the difference between Static head & Manometric head in centrifugal pump.

Description : State the difference between Static head & Manometric head in centrifugal pump.

Last Answer : Static head: The sum of suction head & delivery head is known as static head.  Manometric head: It is the total head that pump is required to develop. This include all losses. This is equal to difference between pressure head at inlet & outlet of pump.

The excess of the sum of pressure & velocity heads over the vaporpressure of the liquid at the suction is called the(A) Static submergence(B) Net positive suction head (NPSH)(C) Cavitation sensitivity(D) Priming

Description : The excess of the sum of pressure & velocity heads over the vaporpressure of the liquid at the suction is called the (A) Static submergence (B) Net positive suction head (NPSH) (C) Cavitation sensitivity (D) Priming

Last Answer : (B) Net positive suction head (NPSH)

Circulation pump is located below the evaporator to (A) Avoid cavitation (B) Avoid frequent priming (C) Create more suction head (D) None of these

Description : Circulation pump is located below the evaporator to (A) Avoid cavitation (B) Avoid frequent priming (C) Create more suction head (D) None of these

Last Answer : (C) Create more suction head

Cavitation can be prevented by (A) Suitably designing the pump (B) Maintaining the suction head sufficiently greater than the vapour pressure (C) Maintaining suction head = developed head (D) Maintaining suction head lower than the vapour pressure

Description : Cavitation can be prevented by (A) Suitably designing the pump (B) Maintaining the suction head sufficiently greater than the vapour pressure (C) Maintaining suction head = developed head (D) Maintaining suction head lower than the vapour pressure

Last Answer : (B) Maintaining the suction head sufficiently greater than the vapour pressure

Thermal efficiency of furnaces can be improved by (A) Waste heat recovery from flue gas (B) Minimising heat losses from furnace walls(C) Maintaining proper draught(D) All (A), (B) and (C

Description : Thermal efficiency of furnaces can be improved by (A) Waste heat recovery from flue gas (B) Minimising heat losses from furnace walls (C) Maintaining proper draught (D) All (A), (B) and (C

Last Answer : (D) All (A), (B) and (C

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

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

Total mechanical losses ( frictional losses , pumping loss in intake and exhaust and power accessories) will amount to a.10-20 % ihp b.2-10 % ihp c.20-30 % ihp d.30 -50 % ihp

Description : Total mechanical losses ( frictional losses , pumping loss in intake and exhaust and power accessories) will amount to a.10-20 % ihp b.2-10 % ihp c.20-30 % ihp d.30 -50 % ihp

Last Answer : a.10-20 % ihp

Pick out the wrong statement about cavitation. (A) Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation (B) Cavitation may be caused due to boiling of liquid by decreasing the pressure resulting in formation & collapse of vapor cavities (C) Cavitation begins at higher static pressure and lower velocity in larger diameter pipelines resulting in audible noise(D) Large scale cavitation cannot damage pipeline, restrict fluid flow anddamage steam turbine blades

Description : Pick out the wrong statement about cavitation. (A) Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation ... (D) Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine blades

Last Answer : (D) Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine blades

Why Cavitation Will Occur In Centrifugal Pumps And Not In Displacement Pumps?

Description : Why Cavitation Will Occur In Centrifugal Pumps And Not In Displacement Pumps?

Last Answer : The formation of cavities (or bubbles) is induced by flow separation, or non-uniform flow velocities, inside a pump casing. In centrifugal pumps the eye of the pump impeller is smaller than ... to increase in temperature in impeller. This air bubbles are transmitted to pump which forms cavitation.

Draw indicator diagram for reciprocating pump showing the effect of accelerating head and frictional head.

Description : Draw indicator diagram for reciprocating pump showing the effect of accelerating head and frictional head.

Last Answer : Draw indicator diagram for reciprocating pump showing the effect of accelerating head and frictional head.

Air vessel provided in a reciprocating pump (A) Smoothens the flow by avoiding pulsations (B) Increases the volumetric efficiency of the pump (C) Saves the pump from the danger of cavitation (D) None of these

Description : Air vessel provided in a reciprocating pump (A) Smoothens the flow by avoiding pulsations (B) Increases the volumetric efficiency of the pump (C) Saves the pump from the danger of cavitation (D) None of these

Last Answer : (D) None of these

Cavitation in a pump creates so many undesirable effects. Out of the following, which is not an undesirable effect created by cavitation? (A) Decrease in effect(B) Increase in thrust(C) Develops noise(D) Develops high pressure

Description : Cavitation in a pump creates so many undesirable effects. Out of the following, which is not an undesirable effect created by cavitation? (A) Decrease in effect (B) Increase in thrust (C) Develops noise (D) Develops high pressure

Last Answer : (D) Develops high pressure

Function of air vessel provided in a reciprocating pump is to (A) Reduce discharge fluctuation (B) Reduce the danger of cavitation (C) Avoid the necessity of priming (D) Increase the pump efficiency

Description : Function of air vessel provided in a reciprocating pump is to (A) Reduce discharge fluctuation (B) Reduce the danger of cavitation (C) Avoid the necessity of priming (D) Increase the pump efficiency

Last Answer : (A) Reduce discharge fluctuation

Air vessel fitted to a reciprocating pump (A) Increases the work done (B) Decreases the work done (C) Causes cavitation (D) Results in non-uniform discharge

Description : Air vessel fitted to a reciprocating pump (A) Increases the work done (B) Decreases the work done (C) Causes cavitation (D) Results in non-uniform discharge

Last Answer : (B) Decreases the work done

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

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

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 large quantities of air at a lower pressure ratio C. Centrifugal compressors are used to supply small quantities of air at a lower pressure ratio D. Centrifugal compressors cannot be run at high speed because of impeller, diffuser and casing.

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

Specific speed of a centrifugal pump depends upon the __________ head. (A) Suction (B) Delivery (C) Manometric (D) None of these

Description : Specific speed of a centrifugal pump depends upon the __________ head. (A) Suction (B) Delivery (C) Manometric (D) None of these

Last Answer : (D) None of these

Net positive suction head (NPSH) of a centrifugal pump must be (A) Greater than the vapour pressure of the liquid (B) Less than the vapour pressure of the liquid(C) Equal to the vapour pressure of the liquid(D) Less than barometric pressure

Description : Net positive suction head (NPSH) of a centrifugal pump must be (A) Greater than the vapour pressure of the liquid (B) Less than the vapour pressure of the liquid (C) Equal to the vapour pressure of the liquid (D) Less than barometric pressure

Last Answer : (A) Greater than the vapour pressure of the liquid

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) NPSH required (B) BHP required by the pump (C) Head of the liquid pumped (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)

Last Answer : (D) All (A), (B) and (C)

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

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

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 in the impeller (C) Mounting of two or more impellers in series on a single shaft (D) Either of (A), (B) or (C)

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

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

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

Head developed by a centrifugal pump depends on its (A) Speed (B) Impeller diameter (C) Both (A) and (B) (D) Neither (A) nor (B)

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)

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

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

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 : 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)

Last Answer : (D) All (A), (B) and (C)

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

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

The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the (A) Discharge (B) Suction (C) Suction minus vapor pressure of the liquid at suction temperature (D) Discharge minus vapor pressure of the liquid at the discharge temperature

Description : The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the (A) Discharge (B) Suction (C) Suction minus vapor ... of the liquid at suction temperature (D) Discharge minus vapor pressure of the liquid at the discharge temperature

Last Answer : (C) Suction minus vapor pressure of the liquid at suction temperature

The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the (A) Discharge (B) Suction (C) Suction minus vapor pressure of the liquid at suction temperature (D) Discharge minus vapor pressure of the liquid at the discharge temperature

Description : The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the (A) Discharge (B) Suction (C) Suction minus vapor ... of the liquid at suction temperature (D) Discharge minus vapor pressure of the liquid at the discharge temperature

Last Answer : (C) Suction minus vapor pressure of the liquid at suction temperature

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 : 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)

Last Answer : (D) All (A), (B) and (C)

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

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

A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump (A) Develops a lower head (B) Capacity is reduced (C) Requires more power (D) All (A), (B) and (C)

Description : A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump (A) Develops a lower head (B) Capacity is reduced (C) Requires more power (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

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

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

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

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

A centrifugal pump designed for handling water (μ = 1 cp) will deliver __________ when pumping a thicker oil (μ = 30 cp). (A) Less head & capacity (B) More head (C) More capacity (D) Less head & more capacity

Description : A centrifugal pump designed for handling water (μ = 1 cp) will deliver __________ when pumping a thicker oil (μ = 30 cp). (A) Less head & capacity (B) More head (C) More capacity (D) Less head & more capacity

Last Answer : (A) Less head & capacity