Question

In: Mechanical Engineering

A centrifugal pump has the following characteristic: outer diameter of impeller 800 mm, width of impeller...

A centrifugal pump has the following characteristic: outer diameter of impeller 800 mm,

width of impeller vanes at outlet 100 mm, angle of impeller vanes at outlet 40 o . The impeller

runs at 550 rpm and delivers 0.98 m 3 /s of water under an effective head of 35 m. A 500 kW

motor is used to drive the pump. Determine the manometric, mechanical and overall

efficiencies of the pump. Assume water enters the impeller vanes radially at inlet.

[ ?mano = 81% , ?m = 83% ?o = 67%].

5. A centrifugal pump has an impeller 0.29 m diameter running at 960 rpm with an effective

outlet vane angle of 28 o . The velocity of the flow (assumed uniform throughout the system)

is 2 m/s. The static suction lift 2.8 m. The energy losses in metres of water are: suction pipe

0.61 m, in impeller 0.49 m, and in volute casing 0.88 m. From these particulars, calculate

the readings of vacuum or pressure gauges placed at (i) inlet of the pump (ii) impeller outlet

(in clearance space between impeller and volute), iii pump outlet or delivery flange located

0.2 m above the centreline of the pump.

[ (i) – 3.614 m, (ii) 6.01 m (iii) 10.89 m ]

6. Water is to be pumped out of a deep well under a total head of 95 m. A number of identical

pumps of design speed 1000 rpm and specific speed 900 rpm with a rated capacity of 150

litres/s are available. How many pumps will be needed and how should they be connected.

[ 3 pumps, connected in series ]

Expert Solution

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samet mamat answered 2 years ago

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