QUESTION $02$

$2\mathrm{.}1$ A multi$-$stage axial turbine is to be design with impulse stage and is oparate with a inlet pressure and temperature of $6$ bar and $900$ k and outlet pressuer of $1$ bar. The isentropic efficiency of the turbine is $85\%.$ All the stage are have a nozzle outlet angle of $75$ and equal inlet and outlet angles. Mean blade speed is $250\frac{m}{s}$ and axial velocity is $150\frac{m}{s}$ and is a constant across the turbine.

$2\mathrm{.}1\mathrm{.}1$ Estimate the number of stages required for this turbine.

$20$