Enhancing the Performance of an Axial Compressor Cascade using Vortex Generators

Abstract

Axial flow compressors have a limited operation range due to the difficulty of controlling the secondary flows. Therefore, a new design of vortex generators is considered in the current investigation to control the secondary flow losses and consequently enhance the compressor’s performance. Different sets of curved side vortex generators with varying configurations are studied to find their effect on the secondary flow losses. Numerical simulations of a three-dimensional compressible turbulent flow have been performed to explore the effect of vortex generators on the reduction of secondary flow losses. Based on the simulation results, the pressure, velocity, and streamline contours are presented to track the development of secondary flows in the compressor cascade. Thus, the total pressure loss and static pressure rise coefficients, blade deflection angles, and diffusion factors are estimated. Results indicate that vortex generators have a significant impact on secondary flow losses such as reducing the corner vortices, and improving the location of separation lines which are moving toward the trailing edge. At the cascade design point, it is found that vortex generators have a significant effect on the reduction of normalized total pressure loss which is evaluated to be up to 20.7%. Using vortex generators do not lead to a significant change in flow deflection and accordingly the off-design conditions will still be far from reached.