General method and application for evaluating system performance and sealing effectiveness of turbine rim seal flow and mainstream at large temperature difference

Abstract

The interaction between the turbine rim seal flow and the mainstream has become a significant limitation on the performance and precision design of large-power turbine systems as the turbine inlet temperature increases. To resolve this issue, this study aims to develop a novel modeling experiment method, capable of effectively analyzing the interaction mechanism and sealing effectiveness of turbine rim seal flow, when subjected to the temperature difference beyond 800 K for both the mainstream and cooling stream. Upon conducting a non-dimensional analysis of the governing equations, a new set of nondimensional parameters, including the Wen number, Wena number, rotating Reynolds number, and flow Reynolds number, is proposed to establish experimental models of high accuracy. Compared to the experimental models built by the conventional parameters of Mach number, rotating Mach number, rotating Reynolds number, and flow Reynolds number, it has proven to be more accurate in predicting sealing performance, improving by approximately 26.1%. Subsequent investigations reveal that these four parameters exhibit varying levels of importance, with the Wen number and Wena number taking precedence over the flow Reynolds number and rotational Reynolds number, respectively. When the flow Reynolds number exceeds 1.0 × 106, its impact can be considered negligible. At a flow Reynolds number of approximately 1.0 × 105, the prediction deviation in sealing effectiveness is less than 0.8% when the flow Reynolds number is reduced by 20%. These findings hold significant implications for enhancing the accuracy of turbine design and minimizing experimental expenses.