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

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
by

1 Answer

Answer :

(B) Higher than
by

Related questions

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

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

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

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

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

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

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

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

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

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)

How Cavitation Can Be Eliminated In A Pump?

Description : How Cavitation Can Be Eliminated In A Pump?

Last Answer : Cavitation means bubbles are forming in the liquid.  To avoid Cavitation, we have to increase the Pump size to One or Two Inch;  To increase the pressure of the Suction Head, or  Decrease the Pump Speed.

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

Foot valves are provided in the suction line of a centrifugal pump to (A) Avoid priming, every time we start the pump (B) Remove the contaminant present in the liquid (C) Minimise the fluctuation in discharge (D) Control the liquid discharge

Description : Foot valves are provided in the suction line of a centrifugal pump to (A) Avoid priming, every time we start the pump (B) Remove the contaminant present in the liquid (C) Minimise the fluctuation in discharge (D) Control the liquid discharge

Last Answer : (A) Avoid priming, every time we start the pump

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) Discharge of water by a centrifugal pump being run at a constant rpm (B) Water flow in the suction and discharge pipe of a reciprocating pump (C) Water discharge from a vertical vessel in which constant level is maintained (D) Low velocity flow of a highly viscous liquid through a hydraulically smooth pipe

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

__________________ is a vapor having a temperature higher than the saturation temperature corresponding to the existing pressure.  a) Vapor  b) Saturated Vapor  c) Superheated Vapor  d) Wet Vapor

Description : __________________ is a vapor having a temperature higher than the saturation temperature corresponding to the existing pressure.  a) Vapor  b) Saturated Vapor  c) Superheated Vapor  d) Wet Vapor

Last Answer : Superheated Vapor

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

Maximum theoretical suction lift for water at 15°C by a centrifugal pump is 34 ft. The same for water at 90°C will be __________ ft. (A) 40 (B) 34 (C) 8 (D) 37

Description : Maximum theoretical suction lift for water at 15°C by a centrifugal pump is 34 ft. The same for water at 90°C will be __________ ft. (A) 40 (B) 34 (C) 8 (D) 37

Last Answer : (C) 8

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

__________________ represents the highest pressure and highest temperature at which liquid and vapor can coexist in equilibrium.  a) Critical Point  b) Boiling Point  c) Quality Point  d) None of the above

Description : __________________ represents the highest pressure and highest temperature at which liquid and vapor can coexist in equilibrium.  a) Critical Point  b) Boiling Point  c) Quality Point  d) None of the above

Last Answer : Critical Point

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

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

Check valve provided in the discharge line of a centrifugal pump serves the purpose of controlling the (A) Back flow of fluid in the event of stoppage of pump (B) Discharge pressure (C) Flow of liquid during operation of the pump (D) All (A), (B) and (C)

Description : Check valve provided in the discharge line of a centrifugal pump serves the purpose of controlling the (A) Back flow of fluid in the event of stoppage of pump (B) Discharge pressure (C) Flow of liquid during operation of the pump (D) All (A), (B) and (C)

Last Answer : (A) Back flow of fluid in the event of stoppage of pump

. 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

In fluid flow, cavitation is caused, if the (A) Fluid velocity decreases to zero (B) Total energy decreases (C) Both (A) and (B) (D) Flow pressure approaches its vapor pressure at the prevailing temperature

Description : In fluid flow, cavitation is caused, if the (A) Fluid velocity decreases to zero (B) Total energy decreases (C) Both (A) and (B) (D) Flow pressure approaches its vapor pressure at the prevailing temperature

Last Answer : (D) Flow pressure approaches its vapor pressure at the prevailing temperature

In thermodynamics, a throttling process, also called a _________, is a type of isenthalpic process where a liquid or gas is cooled as it passes from a higher pressure state to a lower pressure state.  a. Rankine Process  b. Carnot Cycle  c. Joule-Thomson process  d. Refrigeration process

Description : In thermodynamics, a throttling process, also called a _________, is a type of isenthalpic process where a liquid or gas is cooled as it passes from a higher pressure state to a lower pressure state.  a. Rankine Process  b. Carnot Cycle  c. Joule-Thomson process  d. Refrigeration process

Last Answer : Joule-Thomson process

A centrifugal pump loses prime after starting. The reason of this trouble may be (A) Incomplete priming (B) Too high a suction lift (C) Low available NPSH and air leaks in the suction pipe (D) All (A), (B), and (C)

Description : A centrifugal pump loses prime after starting. The reason of this trouble may be (A) Incomplete priming (B) Too high a suction lift (C) Low available NPSH and air leaks in the suction pipe (D) All (A), (B), and (C)

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

If the discharge of a centrifugal pump is throttled, then its suction lift (A) Increases (B) Decreases (C) Remains unchanged (D) Data insufficient to predict

Description : If the discharge of a centrifugal pump is throttled, then its suction lift (A) Increases (B) Decreases (C) Remains unchanged (D) Data insufficient to predict

Last Answer : (A) Increases

The main drawback of centrifugal pump is a)necessity of priming b) discharge from pump varies with the load of water c) For high heads efficiency is low up to 50% d) the suction lift is limited to 6 metre e) all of the above*

Description : The main drawback of centrifugal pump is a)necessity of priming b) discharge from pump varies with the load of water c) For high heads efficiency is low up to 50% d) the suction lift is limited to 6 metre e) all of the above*

Last Answer : e) all of the above*

The pressure of the vapor phase of a substance that is in equilibrium with the liquid or solid phase.  a. Phase Pressure  b. Equilibrium Vapor Pressure  c. Specific Pressure  d. Equilibrium Phase Pressure

Description : The pressure of the vapor phase of a substance that is in equilibrium with the liquid or solid phase.  a. Phase Pressure  b. Equilibrium Vapor Pressure  c. Specific Pressure  d. Equilibrium Phase Pressure

Last Answer : Equilibrium Vapor Pressure

Which is NOT a correct statement?  A. A superheated vapor will not condense when small amount of heat re removed  B. An ideal gas is a gas that is not a superheated vapor  C. A saturated liquid can absorb as much heat as it can without vaporizing  D. Water at 1 atm and room temperature is subcooled

Description : Which is NOT a correct statement?  A. A superheated vapor will not condense when small amount of heat re removed  B. An ideal gas is a gas that is not a superheated vapor  C. A saturated ... absorb as much heat as it can without vaporizing  D. Water at 1 atm and room temperature is subcooled

Last Answer : An ideal gas is a gas that is not a superheated vapor

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

To handle smaller quantity of fluid at higher discharge pressure, use a __________ pump. (A) Reciprocating (B) Centrifugal (C) Volute (D) Rotary vacuum

Description : To handle smaller quantity of fluid at higher discharge pressure, use a __________ pump. (A) Reciprocating (B) Centrifugal (C) Volute (D) Rotary vacuum

Last Answer : (A) Reciprocating

_________________ is one which has a pressure higher than the saturation pressure corresponding to the existing temperature.  a. Saturation Temperature  b. Sub cooled Liquid  c. Compressed Liquid  d. Saturated Liquid

Description : _________________ is one which has a pressure higher than the saturation pressure corresponding to the existing temperature.  a. Saturation Temperature  b. Sub cooled Liquid  c. Compressed Liquid  d. Saturated Liquid

Last Answer : Compressed Liquid

What refers to a liquid whose temperature is lower than saturation temperature corresponding to the existing pressure?  a. Subcooled liquid  b. Saturated liquid  c. Pure liquid  d. Compressed liquid

Description : What refers to a liquid whose temperature is lower than saturation temperature corresponding to the existing pressure?  a. Subcooled liquid  b. Saturated liquid  c. Pure liquid  d. Compressed liquid

Last Answer : Subcooled liquid

________________ is one which has a temperature lower than the saturation temperature corresponding to the existing pressure.  a. Saturation Temperature  b. Sub cooled Liquid  c. Compressed Liquid  d. Saturated Liquid

Description : ________________ is one which has a temperature lower than the saturation temperature corresponding to the existing pressure.  a. Saturation Temperature  b. Sub cooled Liquid  c. Compressed Liquid  d. Saturated Liquid

Last Answer : Sub cooled Liquid

Adiabatic heating and Adiabatic cooling really means _________ and _________ respectively.  a. raising the temp and lowering the temp  b. maintaining the pressure and changing the temperature  c. decreasing the volume and increasing the pressure  d. lowering the temp and raising the temp

Description : Adiabatic heating and Adiabatic cooling really means _________ and _________ respectively.  a. raising the temp and lowering the temp  b. maintaining the pressure and changing the temperature  c. decreasing the volume and increasing the pressure  d. lowering the temp and raising the temp

Last Answer : raising the temp and lowering the temp

A centrifugal pump is required to be primed before starting if it is located (A) At higher level than water level of reservoir (B) At lower level than water level of reservoir (C) Both (a) and (b) (D) Neither (a) nor (b)

Description : A centrifugal pump is required to be primed before starting if it is located  (A) At higher level than water level of reservoir  (B) At lower level than water level of reservoir  (C) Both (a) and (b)  (D) Neither (a) nor (b) 

Last Answer : (A) At higher level than water level of reservoir

__________ pump is the most suitable device for discharging a liquid against a pressure of ≥ 1500 kgf/cm2 . (A) Centrifugal (B) Piston (C) Plunger (D) Vane

Description : __________ pump is the most suitable device for discharging a liquid against a pressure of ≥ 1500 kgf/cm2 . (A) Centrifugal (B) Piston (C) Plunger (D) Vane

Last Answer : (C) Plunger

A 0.064 kg of octane vapor (MW = 114) is mixed with0.91 kg of air (MW = 29.0) in the manifold of an Engine. The total pressure in the manifold is 86.1 kPa, and a temperature is 290 K. assume octane behaves ideally. What is the partial pressure of the air in the mixture in KPa?  a. 46.8  b. 48.6  c. 84.6  d. 64.8

Description : A 0.064 kg of octane vapor (MW = 114) is mixed with0.91 kg of air (MW = 29.0) in the manifold of an Engine. The total pressure in the manifold is 86.1 kPa, and a temperature is 290 K. assume octane behaves ideally. What is ... of the air in the mixture in KPa?  a. 46.8  b. 48.6  c. 84.6  d. 64.8

Last Answer : 84.6

What is the temperature when water and vapor are in equilibrium with the atmospheric pressure?  a. Ice point  b. Steam point  c. Critical point  d. Freezing point

Description : What is the temperature when water and vapor are in equilibrium with the atmospheric pressure?  a. Ice point  b. Steam point  c. Critical point  d. Freezing point

Last Answer : Steam point

At steam point, the temperature of water and its vapor at standard pressure are:  a. Extremes or maximum  b. unity  c. in equilibrium  d. undefined

Description : At steam point, the temperature of water and its vapor at standard pressure are:  a. Extremes or maximum  b. unity  c. in equilibrium  d. undefined

Last Answer : in equilibrium

What is the temperature when water and vapor are in the equilibrium with the atmospheric pressure?  a. Ice point  b. Steam point  c. Critical point  d. Freezing point

Description : What is the temperature when water and vapor are in the equilibrium with the atmospheric pressure?  a. Ice point  b. Steam point  c. Critical point  d. Freezing point

Last Answer : Steam point

_____________ is the difference between the actual temperature of superheated vapor and the saturation temperature for the existing pressure.  a) Degrees of Superheat, °SH  b) Degrees of Sub cooled, °SB  c) Both a and b  d) None of the above

Description : _____________ is the difference between the actual temperature of superheated vapor and the saturation temperature for the existing pressure.  a) Degrees of Superheat, °SH  b) Degrees of Sub cooled, °SB  c) Both a and b  d) None of the above

Last Answer : Degrees of Superheat, °SH

___________________ is a vapor at the saturation conditions (saturation temperature and saturation pressure).  a) Vapor  b) Saturated Vapor  c) Superheated Vapor  d) Wet Vapor

Description : ___________________ is a vapor at the saturation conditions (saturation temperature and saturation pressure).  a) Vapor  b) Saturated Vapor  c) Superheated Vapor  d) Wet Vapor

Last Answer : Saturated Vapor

The temperature at which the vapor pressure exactly equals one atm is called _________.  a. boiling temperature  b. normal boiling point  c. triple point  d. point of infliction

Description : The temperature at which the vapor pressure exactly equals one atm is called _________.  a. boiling temperature  b. normal boiling point  c. triple point  d. point of infliction

Last Answer : normal boiling point

On a day when the partial pressure of water vapor remains constant, what happens as the temperature rises?  a. the relative humidity increases  b. the relative humidity decreases  c. the relative humidity remains constant  d. the air would eventually become saturated

Description : On a day when the partial pressure of water vapor remains constant, what happens as the temperature rises?  a. the relative humidity increases  b. the relative humidity decreases  c. the relative humidity remains constant  d. the air would eventually become saturated

Last Answer : the relative humidity decreases

_________is the partial pressure of water vapor at the existing temperature divided by the equilibrium vapor pressure of water at the existing temperature.  a. vacuum pressure  b. relative humidity  c. absolute pressure  d. vapor pressure

Description : _________is the partial pressure of water vapor at the existing temperature divided by the equilibrium vapor pressure of water at the existing temperature.  a. vacuum pressure  b. relative humidity  c. absolute pressure  d. vapor pressure

Last Answer : relative humidity

Vapor pressure depends only on _________.  a. pressure  b. force  c. volume  d. temperature

Description : Vapor pressure depends only on _________.  a. pressure  b. force  c. volume  d. temperature

Last Answer : temperature

Water boils when:  A. Its saturated vapor pressure equals to the atmospheric pressure  B. Its vapor pressure equals 76cm of mercury  C. Its temperature reaches 212 degree Celsius  D. Its vapor pressure is 1 gram per sq. cm

Description : Water boils when:  A. Its saturated vapor pressure equals to the atmospheric pressure  B. Its vapor pressure equals 76cm of mercury  C. Its temperature reaches 212 degree Celsius  D. Its vapor pressure is 1 gram per sq. cm

Last Answer : Its saturated vapor pressure equals to the atmospheric pressure

In case of an unsaturated mixture of gas and vapor, the percentage saturation is __________ its relative saturation. (A) Lower than (B) Higher than (C) Equal to (D) Either (A) or (B), depends on the mixture composition

Description : In case of an unsaturated mixture of gas and vapor, the percentage saturation is __________ its relative saturation. (A) Lower than (B) Higher than (C) Equal to (D) Either (A) or (B), depends on the mixture composition

Last Answer : (A) Lower than