Cascade testing for a subsonic compressor linear cascade and its modification

In order to compare the aerodynamic performance of a compressor airfoil and its modification airfoil with short chord, the linear cascade tests for the baseline and modified airfoils were conducted in a high subsonic cascade wind tunnel. Before the formal experiment, the inflow uniformity and outflow periodicity were checked under the test condition with and without the test cascade, and the measurement blade passage was determined to meet the test requirement. By cascade experiments, the outlet total pressure, outlet flow angle, and the isentropic Mach number distribution on the baseline and modified cascades were obtained and analyzed. The experimental results show that the loss of the modified cascade is larger than that of the baseline, due to the larger adverse pressure gradient after the peak isentropic Mach number position caused by the larger curvature change of the modified cascade. At the design inlet Mach number 0.6, the incidence range with low total pressure loss of the modified cascade is three degrees larger than that of the baseline cascade, and both the baseline and the modified cascades show good loss characteristics under negative incidence condition. At the design incidence angle (i=0°), the wake profile depth of the baseline and modified cascades increases with the inlet Mach number 0.4~0.7. But when the inlet Mach number reaches the critical value of 0.8, both the depth and the width of the wake profile of the baseline and the modified cascades increase.