Analysis by computer simulation of a combined gas turbine and steam turbine (COGAS) system for marine propulsion

There is a large amount of heat energy available in the exhaust of a gas turbine, and this can be recovered in a heat recovery steam generator to produce additional power to the propulsion system or to electrical power. This concept is known as COGAS; that is, combined gas turbine and steam turbine. When used in a propulsion system, a COGAS plant has to satisfy the requirements of ship propulsion under all possible operating conditions. The performance of a COGAS system, particularly the gas turbine cycle, varies with the atmospheric conditions such as temperature, pressure and relative humidity. A dynamic analysis of COGAS propulsion plants is useful for predicting system performance and providing guidance for system design. The codes for the simulation performed in this study are developed with MATLAB/Simulink. This paper presents a dynamic simulation of a COGAS propulsion system with MATLAB/Simulink. Results of the simulation are discussed and presented in the paper.