# Mechanical Engineering - Hydraulic Machines - Discussion

Discussion Forum : Hydraulic Machines - Section 1 (Q.No. 6)
6.
Discharge of a centrifugal pump is
directly proportional to diameter of its impeller
inversely proportional to diameter of its impeller
directly proportional to (diameter)2 of its impeller
inversely proportional to (diameter)2 of its impeller
Explanation:

Discharge of a centrifugal pump is directly proportional to (Diameter)^2 of its impeller.

Head of a centrifugal pump is directly proportional to (Diameter)^2 of its impeller.

Power Developed of a centrifugal pump is directly proportional to (Diameter)^4 of its impeller.

Discussion:
49 comments Page 1 of 5.

Samuel said:   2 years ago
I think, here It should be Discharge Head.

And accordingly, option C would be correct.

DebashisD said:   2 years ago
Discharge = Q * D * N.
(1)

Shaik Murtuza said:   4 years ago
Option A is the correct answer.
(1)

Hrushi Nikam said:   4 years ago
When we calculate for specific speed we take the assumption of B being proportional to Diameter. So, option C is correct.

Fouziahussain said:   4 years ago
Q=(pi)DbV.

D=Diameter of impeller.
B =Width.
V= Velocity of flow.

Prithvi singh said:   5 years ago
Q is directly proportional to D^3.
(4)

Engr Aamir said:   5 years ago
If Q=Av then Q is directly or inversely proportional?

Biswajit Das said:   5 years ago
Option C is correct.
That Q= π D b Vf.
Anyhow Vf is related to V and V is related to u and u =π D N /60.
So, Q is directly proportional to D^2.
(1)

Sekhar mullapudi said:   5 years ago
The discharge flow rate is directly proportional to its diameter.

But here the question is an only discharge of centrifugal pump; So the answer is "directly proportional to the square of the diameter".

So, the correct option C is correct.

Utsav said:   6 years ago
No, the Discharge of a centrifugal pump is Directly proportional to Impeller diameter.

You can refer to below-given affinity laws.

Q1/Q2 = D1/D2.
H1/H2 = (D1/D2)^2,
P1/P2 = (D1/D2)^3.

Q Indicates Flow that is discharged,