Question

Question 3: (a) Name four parts of a centrifugal pump and explain their respective function [6 marks] (b) A 97% efficiency, 10kW motor is powering a 95% overall efficiency centrifugal pump with head loss of 0.75m and Mechanical loss of 90W. Find the water leakage rate if the flow rate is 0.025m'/s. The gravity constant is g 9.81m/s and the density of water is p 998kg/m3 [6 marks] (c) A water jet of diameter 50mm is striking a Pelton wheel of diameter 1.5m. The wheel bucket friction is 0.85 and the deflecting angle is 165°. If the system is currently generating 50kW of electricity at 90% overall efficiency, determine: the jet velocity, and (i) 17 marks] (ii) the wheel angular velocity [6 marks]

Answer 1

A) Parts of a centrifugal pump

1. Impeller – It imparts energy received from the motor to fluid inside the impeller and increases pressure. Impeller is the main part of the centrifugal pump.
2. Casing – An airtight chamber which surrounds the impeller.
3. Suction pipe - Pipe connecting sump level to inlet of the pump. Suction pipe delivers fluid from sump level to impeller casing with the help of impeller.
4. Delivery pipe - Pipe connected to the output of the pump and delivers fluid to desired place/height.

c> Problem on Polton .lurbine 2. 165

138. 3322m) 298 1 x 75.1256 60 60 60 가heel ou

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