Numerical Analysis Of The Flow In Low-Spped Axial Compressors With Circumferentially Skewed Blades Using A Streamline Curvature Approach

The techniques of sweep and dihedral have been widely used in turbomachinery with the advantage of reducing flow loss, particularly in turbines. However, there is a discrepancy between the flow in compressors and turbines due to the adverse pressure gradient in compressors, which makes it necessary to conduct a further investigation in the application of sweep and dihedral in compressors, especially in rotors.This paper studies the aerodynamic performance of a low-speed axial flow compressor with circumferentially skewed blades using a streamline curvature approach. As a modification to the fundamental S2 stream surface through-flow calculation, stations are set up in blade passages and body forces are introduced to simulate the effects of blades on airflow with the purpose of taking blade skew into consideration. A research into the development of loss and deviation models is also carried out, and correlations that give better performance predictions are adopted.The streamline curvature code is written in FORTRAN language. Simulation of the last three stages of an eight-stage compressor at design condition is performed, and a comparison with experimental results indicates that the loss and deviation models give reasonable and accurate results. Secondly this work discusses the influence of skew direction and magnitude of skew angle on axial flow compressor performance.Finally, numerical simulation is carried out using NUMECA-Fine/Turbo solver, which verifies the results of the streamline curvature code. A further investigation is performed to analyze the impact of skew direction on the flow of low-speed axial flow compressors. The calculation results show that the streamline curvature method is able to assess the effects of blade skew efficiently and provide reference for the design of circumferentially skewed blades in the preliminary stage of compressor design.