Mathematical Modeling and Computer Simulation of a Combined Cycle Power Plant

This paper presents the simulation procedure developed to predict the performance of a combined cycle power plant from given performance characteristics of its main components. Effects of gas turbine and steam turbine cycle parameters on combined cycle power plant (CCPP) output in terms of efficiency, work output and power output, particularly analyzing the influence of ambient conditions on the plant performance. The results of the mathematical model, implemented in "Matlab" software, have been compared with the simulation results presented in literature. Result shows that as the compression ratio increase the increase in efficiency becomes less. Increase in work output is observed upto a pressure ratio of 18 after this it starts decreasing. Increase in TIT increases cycle work output and efficiency. Turbine outlet temperature decreases with increase in compression ratio. Combined cycle efficiency and output first increases with rise in drum pressure and then decreases. Increasing superheater temperature is found to increase the specific work output and efficiency of steam and combined cycle. Increasing superheater temperature is found to increase the specific work output and efficiency of steam and combined cycle. Lowering the pinch point and approach point also results in an improvement in the combined cycle performance, Specific heats are considered to be changing with temperature. The present work will make the base for exergy analysis of combined cycle for varying parameters.