Railways NTPC (Technical Ability) Turbomachinery Question Bank Turbomachinery

  • question_answer
                              A single-stage impulse 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) \[45{}^\circ \]m/s                     

    D) 900 m/s         

    Correct Answer: C

    Solution :

    \[u=\frac{\pi DN}{60}=\frac{\pi \times 1.2\times 300}{60}=188.5\,\,\text{m/s}\] \[\rho =\frac{u}{{{v}_{a\,1}}}\] \[{{v}_{a\,1}}=\frac{188.5}{0.42}=4488=45{}^\circ \text{m/s}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner