A combined power plant consisting of a simple open cycle gas turbine unit, using air as the working fluid (neglect fuel mass flow rate), and a steam turbine is to be designed such that the heat rejected at the gas turbine unit is to be utilized to produce steam at the generator for the steam turbine. The exhaust air leaving the generator is at (200°C). Draw a simple sketch for the plant and the (T-s) diagram and calculate the mass flow rate of steam per (kg/s) of airflow, the total power output per (kg/s) of airflow and the overall thermal efficiency of the plant. Assume ideal cycles. Neglect the feed pump work of Rankine cycle. The data of each cycle are as follows:

 

Gas Turbine Cycle Steam Turbine Cycle Pressure Minimum 1 0.07 (bar) Temperature (C) Maximum 5 30 Minimum 20 Maximum 830 300 Assume the following: a) For the Compression process Cpa = 1.005 (). k = 1.4 b) Combustion and Expansion process Cpg = 1.15 (). k = 1.333 %3D