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Diameter of impeler of centrifugal pump inlet and outlet are 30 cm and 60 cm respectively. velocity of flow at outlet 20m/sec and vanes are set back at angle 45 outlet.Determine minimum

starting speed of pump if manometer efficiency is 70%

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Given :

D1=30cm=0.3 m

D2=60cm =0.6 m

nmano=0.7

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tanϕ=Vs2u2Vw2

i.e tan45=2U2Vw2

VW2=u22

nmano=g.Hm(u222)u2

0.7=9.81×Hm(u22)u2

Hm=0.0714(u2-2)u2

Let N be the minimum speed of the pump required for starting

Vane velocity at exit V2=πD2N60=π×0.6×N60=0.03142 N

Vane velocity at inlet u1=πD1N60=π×0.3×N60=0.01571 N

Condition for minimum starting …

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