# Mechanical Engineering - Hydraulic Machines - Discussion

Discussion Forum : Hydraulic Machines - Section 1 (Q.No. 1)
1.
Power required to drive a centrifugal pump is directly proportional to __________ of its impeller.
diameter
square of diameter
cube of diameter
fourth power of diameter
Explanation:
No answer description is available. Let's discuss.
Discussion:
34 comments Page 1 of 4.

Nani said:   1 year ago
As per affinity law, break horse power is directly proportional to cube of diameter or cube of rpm.
(4)

Sai khelwane said:   4 years ago

Evans siripi said:   5 years ago
I think the answer is D.

Raj said:   5 years ago

Deepak Rathva said:   6 years ago

Ref: R.K.Bansal.

Sullahe sanu said:   6 years ago

Sandeep said:   6 years ago
d^4 will be the correct answer. Since the question is asked as directly proportional the tangent flow of an impulse turbine always takes 4th power to diameter.
(2)

Pushpender said:   6 years ago
Affinity laws applied to axial and radial flows pumps and turbines. Its a tangent flow ; impulse turbine so I think 4th power is correct.

Sharan said:   6 years ago
Ans: C is correct.

i.e d^3--p=TW=(Tou*pi*d^3/16*T)*(v/r).

Manish said:   7 years ago
Note that there are two sets of affinity laws:.

Affinity laws for a specific centrifugal pump - to approximate head, capacity and power curves for different motor speeds and /or different diameter of impellers.

Affinity laws for a family of geometrically similar centrifugal pumps - to approximate head, capacity and power curves for different motor speeds and /or different diameter of impellers.