The application of modern Computational Fluid Dynamics techniques for increasing the efficiency and stability of an axial compressor in an industrial gas turbine

Abstract

This paper contains on-site test data of an axial compressor as part of an industrial gas turbine, as well as the process of Computational Fluid Dynamics (CFD) modelling, verification, research and modernization. The research method has been verified with actual test data gathered from the real gas turbine unit (GTU) test. The computational studies showed significant potential for improving aerodynamic efficiency and the surge margin of a compressor by better matching of inlet and outer groups of stages. A special design approach was used to improve aerodynamic parameters of the inlet system and certain middle stages. Computations made for the improved compressor model showed a 3% efficiency gain and 5% stall margin gain with possibilities for further modernization. Keywords: axial compressor of gas turbine, CFD computations, profiling of compressor blades, verification of computational model.

Redesign of an Axial Compressor With Mass Flow Reduction of 30%

“…Previous experience [1], [7] has shown too optimistic prediction of a mass flow comparing to the real compressor. This was explained by miss-prediction of the size of separation zones at the end-walls.…”

“…Though, it was expected to reduce the isentropic efficiency of the compressor by about 2%. Similar re-design project was carried earlier on for better stage matching (see [1]).…”

Identification of corner separation modelling in axial compressor stage

“…One of the key factors determining the efficiency of a gas turbine engine is the performance of an axial compressor and turbine. Since the flow in axial turbomachines is generally three-dimensional, it is important to consider a appropriate flow operating point in the blade channels [3].…”