Hi, I need help understanding how they got the values for H2 and S2? Were they interpolated and how? Many thanks to who can answer :) Here's the question taken from the book Introduction Chemical Engineering Thermodynamics by Smith, Van Ness, Abbott, and Swihart: Steam enters the turbine of a power plant operating on the Rankine cycle (Fig. 8.3) at 3300 kPa and exhausts at 50 kPa. To show the effect of superheating on the performance of the cycle, calculate the thermal efficiency of the cycle and the quality of the exhaust steam from the turbine for turbine-inlet steam temperatures of 450, 550, and 650C.

Case-1: Turbine pressure = 3300 kPa Calculate the work done by the pump using following expression: Wump [V.(P.-P)] = 1.030 cm 10m 1000 gm *(3300 kPa - 50 kPa) gm 1 cm 1 kg kJ 3.348 kg Now, the enthalpy at boiler is as follows: H = H, + Wum kJ = 340.564 kJ +3.348 kg kg = 343.911 kJ kg The initial temperature is 450 C and the boiler pressure is 3300 kPa. So, calculate the enthalpy and entropy values from steam tables at these conditions. kJ kJ H, = 3340.6 and S, - 7.0373 kg The step from 2-3 is isentropic. So, S, ES, Now, calculate the quality of exhaust steam using following expression: 7.0373 kJ - 1.0912 k] kg K x = kg K kJ kJ 7.5947 -1.0912 kg K = 0.914 = kg K kg K