Comparative Analysis of STIG Cycles and Postcombustion Influence

A methodology to evaluate the performances of STIG cycles has been carried out in this study, based on remarkable parameters such as steam injected fraction, gas and steam specific work and their respective heat amounts supplied in the combustor. The survey has been carried out on two different kind of gas turbines: heavy duty and aeroderivative gas turbines. Suitable amounts of cooling air with regard to the various kinds of gas turbines have been calculated. The results achieved with the proposed methodology agree with the data put forth in the literature on the subject and are a reference for more complex STIG cycles such as the postcombustion case. In the latter case the postcombustion has not proved convenient for STIG cyclesm as regards efficiency, but it involves benefits as greater maximum powers are obtainable