Centrifugal Pumps and Hydraulic Energy Conversion Quiz

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What is the primary function of a centrifugal pump?

Convert electrical energy into pressure energy
Convert pressure energy into rotational energy
Convert mechanical energy into pressure energy (correct)
Convert hydraulic energy into mechanical energy

How does the flow occur in centrifugal pumps?

Radial outward direction (correct)
Circular motion
Random chaotic flow
Axial inward direction

What type of flow principle does a centrifugal pump work on?

Forced vortex flow (correct)
Natural convection flow
Laminar flow
Turbulent flow

What part of a centrifugal pump is responsible for rotating the liquid?

Impeller (A) Signup and view all the answers

How does the rise in pressure head in a centrifugal pump vary with the tangential velocity of the liquid?

It is proportional to the square of velocity (B) Signup and view all the answers

Which part of a centrifugal pump is connected to the shaft of an electric motor?

'Impeller' (B) Signup and view all the answers

What is the precaution against cavitation related to the pressure of the flowing liquid in the hydraulic system?

Maintaining the pressure above the vapour pressure of the liquid (B) Signup and view all the answers

What effects are observed due to cavitation on turbine blades?

Roughening of the surface due to pitting action (B) Signup and view all the answers

How is Net Positive Suction Head (NPSH) defined?

The pressure at the inlet of the pump minus the vapour pressure head plus velocity head (C) Signup and view all the answers

How is NPSH related to cavitation-free pump operation?

Available NPSH should be greater than the required NPSH (C) Signup and view all the answers

What distinguishes between the required and available NPSH for a pump installation?

Required NPSH is determined experimentally while available NPSH is given by the pump manufacturer (B) Signup and view all the answers

What materials are recommended as a precaution against cavitation?

Aluminium and steel (C) Signup and view all the answers

What is the main function of the casing surrounding the impeller in a centrifugal pump?

To convert kinetic energy into pressure energy (A) Signup and view all the answers

What is the purpose of a foot valve in the suction pipe of a centrifugal pump?

To prevent backflow of water from the pump (D) Signup and view all the answers

In a multistage centrifugal pump, impellers connected in series are used primarily to:

Produce high head (C) Signup and view all the answers

What is the main function of connecting impellers in parallel in a multistage centrifugal pump?

To increase pressure (B) Signup and view all the answers

Which phenomenon describes the formation of vapor bubbles in a flowing liquid due to pressure drop?

Cavitation (B) Signup and view all the answers

In a centrifugal pump, what occurs when the pressure of the flowing liquid falls below its vapor pressure?

Boiling (B) Signup and view all the answers

What action causes pitting on metallic surfaces due to cavitation in pumps?

Collapsing of vapor bubbles (C) Signup and view all the answers

What is the primary reason for connecting multiple impellers on the same shaft in a multistage pump?

To increase head. (C) Signup and view all the answers

What is the role of a strainer at the lower end of a suction pipe connected to a centrifugal pump?

Filter out debris. (B) Signup and view all the answers