Topic: Power Plant Engineering
A single-stage impulse turbine with a diameter of 120 cm runs at 3000 rpm. If the blade speed ratio is 0.42, then, the inlet velocity of steam will be-
- A. $79~m/s$
- B. $188~m/s$
- C. $450~m/s$
- D. $900~m/s$
Answer: C. $450~m/s$
Explanation: In single stage impulse turbine, diameter $D=120~cm=1.2~m$, $N=3000~rpm$. Blade speed $U = \frac{\pi DN}{60} = \frac{\pi \times 1.2 \times 3000}{60} = 188.49~m/s$. Blade speed ratio = $\frac{U}{V} = 0.42$. Thus, Inlet velocity $V = \frac{188.49}{0.42} = 448.798 \approx 450~m/s$.