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Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg.K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg.K, entropy of saturated vapour = 7.2234 kJ/kg.K) The exit condition of steam is

Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg.K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg.K, entropy of saturated vapour = 7.2234 kJ/kg.K) The exit condition of steam is Correct Answer Superheated vapour

For an isentropic process $$s{\text{ }}initial = s{\text{ }}final{\text{ }}\left( {exit} \right)$$
$$\eqalign{ & \Rightarrow 6.65 = {S_{liq}} + x\left( {{S_{liq}} - {\text{ }}{S_v}} \right) \cr & \Rightarrow 6.63 = 1.4336 + x\left( {7.2234 - 1.4336} \right) \cr & \Rightarrow x = 0.9 \cr} $$
So, we are getting partially condensed vapour with quality = 0.9.

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