# 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 2 of 5.

ANGARI ABHINAY said:   6 years ago
Discharge of centrifugal pump formula π*D*b*V,
Also, Discharge Head is directly proportional to D^2,
Power is Directly proportional to N^3.

Honey said:   8 years ago
I think, All the options are not satisfied. The correct answer will be directly proportional to the cube of the diameter of vanes.

Ashutosh said:   7 years ago
According to affinity law.

Flow or discharge is directly proportional to impeller diameter if the speed of the shaft is constant.

Venkat said:   7 years ago

Discharge of centrifugal pump is directly proportional to its (dia)^2.
Q = A * V,
Here A = π * D^2/4.

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.

Shiva said:   7 years ago
As Q is directly proportional to B and D and B (width) is proportional to D. Therefore Q is directly proportional to D^2.

Bapi said:   6 years ago
Q/{N(D^3)}=constant.
So the correct answer is Q is directly proportional to cube of the diameter(D) of the impeller.

Discharge of centrifugal pump is given by Q = (pi)(D2)(B2)(Vf2).

As per above equation option (A) is correct.

Parameswararao said:   7 years ago
Is directly proportional to the square of the diameter (refer R. K. Rajput textbook pg no. 1219).

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

And accordingly, option C would be correct.