Análise de desempenho de uma microturbina a gás industrial operando em ciclo regenerativo modificado

Abstract

The present study has as main focus to perform the performance analysis of a Capstone C30 industrial microturbine operating under a modified regenerative cycle, in which the exhaust gases of a high pressure turbine, through the regenerator are used to power a low pressure turbine, drawing power from the low pressure turbine. The objective of this study is to compare the performance of this cycle, between an ideal analysis, without considering losses and efficiencies, and in a real analysis. For this analysis, the Brayton cycles were ideally modeled, regenerative and modified, using thermodynamic relationships and then simulated in the gas turbine performance analysis software, DESTUR. Evaluating the ideal results, it was observed a 15.5% greater efficiency obtained by the modified regenerative cycle, when compared to the conventional regenerative cycle under the same operating conditions. Specific work drops due to modifications of the microturbine operation to off-design were observed. After simulations, it was found that the consideration of component efficiencies, pressure losses and variations in fluid composition directly affect performance, in which efficiency was shown to be 14.75% lower compared to the conventional regenerative cycle and specific work, in line with ideal behavior, has been reduced. It was found that for high cycle pressure ratio values, the proposed modification is confirmed by obtaining greater efficiencies and specific work, when compared to the conventional regenerative cycle under the same operating conditions, but not being applicable to the Capstone C30 microturbine, due its smaller features and limitations.