Topic: Fluid Machinery
A centrifugal pump with peripheral speed 'V' was selected for a total lift of 100 m. Actually pump was to be operated for a total lift of 400m. The peripheral speed should actually be (other conditions remaining same)
- A. 2V
- B. 4V
- C. 8V
- D. 1V
Answer: A. 2V
Explanation: Given $V_{1}=V$, $H_{1}=100m$, $H_{2}=400m$. We know $\frac{H_{1}}{N_{1}^{2}}=\frac{H_{2}}{N_{2}^{2}}$ and peripheral speed $V \propto N$. Therefore, $\frac{H_1}{V_1^2} = \frac{H_2}{V_2^2} \implies \frac{100}{V^{2}}=\frac{400}{V_{2}^{2}} \implies V_{2}^{2}=4V^{2} \implies V_{2}=2V$.