# Power required to drive a centrifugal pump is

By BYJU'S Exam Prep

Updated on: October 17th, 2023

(a) Directly proportional to speed of its impeller

(b) Directly proportional to square of the speed of its impeller

(c) Directly proportional to cube of the speed of its impeller

(d) Inversely proportional to cube of the speed of its impeller

Power required to drive a centrifugal pump is directly proportional to cube of the speed of its impeller. The power of the centrifugal pump is given by, P = ρQgHm/1000 i.e. P ∝ Q × Hm

### Power required to drive a Centrifugal Pump

From model law of the pump: Q/ND3 = C

• Q ∝ D3 × N
• i.e. P ∝ D3 × N × Hm

From the model law of the pump: Hm/N2D2 = C

• Hm ∝ N2 × D2
• i.e. P ∝ D3 × N × D2 × N2
• P ∝ D5 × N3
• P ∝ N3
• i.e. the power of a centrifugal pump is directly proportional to the cube of the impeller speed.

Summary:

## Power required to drive a centrifugal pump is (a) Directly proportional to speed of its impeller (b) Directly proportional to square of the speed of its impeller (c) Directly proportional to cube of the speed of its impeller (d) Inversely proportional to cube of the speed of its impeller

The power needed to drive a centrifugal pump is proportional directly to the cube of the speed of the impeller. The impeller is a mechanical device designed to move a fluid through the transfer of rotational energy from one or more driven rotors.

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