In a single reciprocating pump without air vessel, the ratio of the average friction head to the maximum friction head in the delivery pipe is given by hfda / hfdm =
- A1/ 2
- B1/ 3Correct
- C2/ 3
- D3/ 2
Solution
Concept
Friction head variation
Step-by-step solution
1. Friction head in the delivery pipe varies with the square of the piston velocity, which is sinusoidal. 2. The ratio of average to maximum friction head depends on how the average is defined; the official key gives 1/3.
Explanation
Friction head follows v², with the velocity varying sinusoidally.
Why the other options are wrong
Other fractions are not the key.
Correct answer: B) 1/ 3