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

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
by

1 Answer

Answer :

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

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

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

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

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

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)

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

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

Probability of cavitation occuring becomes very high, when the local __________ resulting in water bubbles formation, which on rupture cause cavitation (A) Pressure falls below the vapour pressure (B) Pressure becomes very high (C) Temperature becomes low (D) All 'a', 'b' & 'c'

Description : Probability of cavitation occuring becomes very high, when the local __________ resulting in water bubbles formation, which on rupture cause cavitation (A) Pressure falls below the vapour pressure (B) Pressure becomes very high (C) Temperature becomes low (D) All 'a', 'b' & 'c'

Last Answer : (D) All 'a', 'b' & 'c'

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

Cavitation will begin when (A) The pressure at any location reaches an absolute pressure equal to the saturated vapour pressure of the liquid (B) Pressure becomes more than critical pressure (C) Flow is increased (D) Pressure is increased

Description : Cavitation will begin when (A) The pressure at any location reaches an absolute pressure equal to the saturated vapour pressure of the liquid (B) Pressure becomes more than critical pressure (C) Flow is increased (D) Pressure is increased

Last Answer : Answer: Option A

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

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

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

Acceleration head in a reciprocating pump (A) Increases the work done during delivery stroke (B) Decreases the work done during suction stroke (C) Does not change the work requirement of the pump (D) Increases the work done during suction stroke

Description : Acceleration head in a reciprocating pump (A) Increases the work done during delivery stroke (B) Decreases the work done during suction stroke (C) Does not change the work requirement of the pump (D) Increases the work done during suction stroke

Last Answer : (C) Does not change the work requirement of the pump

Horsepower requirement for given pump capacity depends upon the (A) Specific gravity of the liquid (B) Suction lift (C) Discharge head (D) All (A), (B) and (C)

Description : Horsepower requirement for given pump capacity depends upon the (A) Specific gravity of the liquid (B) Suction lift (C) Discharge head (D) All (A), (B) and (C)

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

What type of pump may be appropriate for a liquid near saturation, a low flow rate, and very limited NPSHa (net positive suction head available)?

Description : What type of pump may be appropriate for a liquid near saturation, a low flow rate, and very limited NPSHa (net positive suction head available)?

Last Answer : This application is nearly perfect for a turbine regenerative type of pump. Factors that immediately identify your application and pump type are the small flowrate, low NPSHa, and high temperature. The ... in pressure. You can visit the site below to learn more about these types of pumps.

Consider the following statements: The total head against which a pump has to work must include, besides any other items, 1. the suction lift. 2. the delivery head. 3. the head lost due to friction at entrance in the rising main. 4. the head lost due to friction at exit in the rising main. Which of these statements are correct? (a) 1, 2 & 3 only (b) 2 & 3 only (c) 1, 2, 3 & 4 (d) 3 & 4 only

Description : Consider the following statements: The total head against which a pump has to work must include, besides any other items, 1. the suction lift. 2. the delivery head. 3. the head lost due to friction at entrance in the rising main. 4. the ... 2 & 3 only (b) 2 & 3 only (c) 1, 2, 3 & 4 (d) 3 & 4 only

Last Answer : (c) 1, 2, 3 & 4

A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a __________ pump. (A) Sump (B) Volute (C) Vacuum (D) Submerged

Description : A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a __________ pump. (A) Sump (B) Volute (C) Vacuum (D) Submerged

Last Answer : (C) Vacuum

Reducing suction pressure in refrigeration cycle (a) lowers evaporation temperature (b) increases power required per ton of refrigeration (c) lowers compressor capacity because vapour is lighter (d) all of the above.

Description : Reducing suction pressure in refrigeration cycle (a) lowers evaporation temperature (b) increases power required per ton of refrigeration (c) lowers compressor capacity because vapour is lighter (d) all of the above.

Last Answer : Ans: d

In vapour compression cycle using NH3 as refrigerant, initial charge is filled at (a) suction of compressor (b) delivery of compressor (c) high pressure side close to receiver (d) low pressure side near receiver

Description : In vapour compression cycle using NH3 as refrigerant, initial charge is filled at (a) suction of compressor (b) delivery of compressor (c) high pressure side close to receiver (d) low pressure side near receiver

Last Answer : Ans: c

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

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

. 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

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

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

Which one of the following statements is correct ? (a) Dynamic viscosity is the property of a fluid which is not in motion (b) Surface energy is a fluid property giving rise to the phenomenon of capillarity in water (c) Cavitation results from the action of very high pressure (d) Real fluids have lower viscosity than ideal fluids

Description : Which one of the following statements is correct ? (a) Dynamic viscosity is the property of a fluid which is not in motion (b) Surface energy is a fluid property giving rise to the phenomenon ... results from the action of very high pressure (d) Real fluids have lower viscosity than ideal fluids

Last Answer : (d) Real fluids have lower viscosity than ideal fluids

Suction lift of a pump depends upon (A) Atmospheric pressure (B) Water temperature (C) Velocity of water in suction pipe (D) All the above

Description : Suction lift of a pump depends upon  (A) Atmospheric pressure  (B) Water temperature  (C) Velocity of water in suction pipe  (D) All the above 

Last Answer : (D) All the above 

The caking of crystals can be prevented by (A) Maintaining high critical humidity (B) Maintaining low critical humidity (C) Coating the product with inert material (D) Both (A) and (C)

Description : The caking of crystals can be prevented by (A) Maintaining high critical humidity (B) Maintaining low critical humidity (C) Coating the product with inert material (D) Both (A) and (C)

Last Answer : (D) Both (A) and (C)

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.

Assume that water vaporizes at an absolute pressure of 1.5 m, barometric pressure head is 9.5 m and cavitation coefficient is 0.1 A turbine operates under a head of 40 m. the safe height of the runner above the tail water level, in meters, is : a) 6 b) 4 c) 3 d) 2

Description : Assume that water vaporizes at an absolute pressure of 1.5 m, barometric pressure head is 9.5 m and cavitation coefficient is 0.1 A turbine operates under a head of 40 m. the safe height of the runner above the tail water level, in meters, is : a) 6 b) 4 c) 3 d) 2

Last Answer : b) 4

The arc resulting from the tripping of a circuit breaker is prevented from damaging the contacts by _____________. A. designing the contacts to open slowly B. directing the arc into an arc chute C. an inverse timed thermal trip for short circuit currents D. instantaneous magnetic trip for overload currents

Description : The arc resulting from the tripping of a circuit breaker is prevented from damaging the contacts by _____________. A. designing the contacts to open slowly B. directing the arc into an ... an inverse timed thermal trip for short circuit currents D. instantaneous magnetic trip for overload currents

Last Answer : Answer: B

In most of the vacuum crystalliser, vacuum is generally produced by means of a (A) Suction pump (B) Compressed air jet (C) Steam jet ejector with a barometric condenser (D) None of these

Description : In most of the vacuum crystalliser, vacuum is generally produced by means of a (A) Suction pump (B) Compressed air jet (C) Steam jet ejector with a barometric condenser (D) None of these

Last Answer : (C) Steam jet ejector with a barometric condenser

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)

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

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

Capacity of a rotary gear pump can be varied by (A) Changing the speed of rotation (B) Bleeding air into suction (C) Bypassing liquid from the suction or discharge line (D) All (A), (B) and (C)

Description : Capacity of a rotary gear pump can be varied by (A) Changing the speed of rotation (B) Bleeding air into suction (C) Bypassing liquid from the suction or discharge line (D) All (A), (B) and (C)

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

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

What is the maximum theoretical suction lift (metres) of a reciprocating pump? (A) 5 (B) 10(C) 50 (D) 100

Description : What is the maximum theoretical suction lift (metres) of a reciprocating pump? (A) 5 (B) 10(C) 50 (D) 100

Last Answer : (B) 10

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

In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to (a) collect liquid refrigerant and prevent it from going to compressor (b) detect liquid in vapour (c) superheat the vapour (d) increase refrigeration effect

Description : In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to (a) collect liquid refrigerant and prevent it from going to compressor (b) detect liquid in vapour (c) superheat the vapour (d) increase refrigeration effect

Last Answer : Ans: a

Effect Of Superheating of suction Vapour-(before compression)

Description : Effect Of Superheating of suction Vapour-(before compression)

Last Answer : Effect Of Superheating of suction Vapour-(before compression) A vapour compression cycle with superheated vapour before compression is shown on T-s and p-h diagrams respectively. In this cycle, the ... . Thus, to avoid this, a 5 to 20 K superheat of the refrigerant is always desirable. 

Bananas can be prevented from over-ripening by (a) maintaining them at room temperature (b) refrigeration (c) dipping in ascorbic acid solution (d) storing in a freezer.

Description : Bananas can be prevented from over-ripening by (a) maintaining them at room temperature (b) refrigeration (c) dipping in ascorbic acid solution (d) storing in a freezer.

Last Answer : (d) storing in a freezer.

The ________ disease can be prevented by maintaining good personal hygiene. a) cholera b)tuberculosis c)ringworm d)malaria

Description : The ________ disease can be prevented by maintaining good personal hygiene. a) cholera b)tuberculosis c)ringworm d)malaria

Last Answer : c)ringworm

A programmer is writing a system that is intended to be able to store large amounts of personal data. As the programmer develops the data system, which of the following is LEAST likely to impact the programmer’s choices in designing the structure of the system? A. Maintaining privacy of the information stored in the data set. B. Scalability of the system. C. Structuring the metadata of the information for analysis. D. The frequency of a particular item occurring in a data set.

Description : A programmer is writing a system that is intended to be able to store large amounts of personal data. As the programmer develops the data system, which of the following is LEAST likely to impact the ... of the information for analysis. D. The frequency of a particular item occurring in a data set.

Last Answer : D. The frequency of a particular item occurring in a data set.

Which of the following would not be an operations function in a fast-food restaurant? (a) making hamburgers and fries ; (b) advertising and promotion (c) maintaining equipment ; (d) designing the layout of the facility

Description : Which of the following would not be an operations function in a fast-food restaurant? (a) making hamburgers and fries ; (b) advertising and promotion (c) maintaining equipment ; (d) designing the layout of the facility

Last Answer : Is not a step in new product Development process?

When the water is warm, the height to which it can be lifted by a pump (A) Decreases due to reduced viscosity (B) Decreases due to reduced vapour pressure (C) Increases due to increased vapour pressure (D) Decreases due to increased frictional resistance

Description : When the water is warm, the height to which it can be lifted by a pump (A) Decreases due to reduced viscosity (B) Decreases due to reduced vapour pressure (C) Increases due to increased vapour pressure (D) Decreases due to increased frictional resistance

Last Answer : (B) Decreases due to reduced vapour pressure