Particle image velocimetry investigations of a subsonic compressor tandem cascade

Abstract

A highly loaded, optimized compressor tandem cascade for low speed application (Ma1 = 0:175) [1, 2] was investigated numerically and experimentally using the standard particle image velocimetry measurement technique. The investigated regions are divided in the inlet, the overlap and the outlet region and are investigated for three different inlet angles. For all inlet angles investigated the results show a homogeneous velocity distribution. The analysis of the measured inlet angle shows a strong suction effect of the cascade starting far in front of the leading edge of the front blade. The acceleration in the overlap region and the change of the velocity distribution is measured for all inlet angles investigated and clarifies the conclusions resulting of former blade surface static pressure measurements [1]. Although the used PIV technique is only capable to resolve two velocity components, the results of the spanwise measured outlet flow fields allow a good analysis of the secondary flow and complete the standard measurement results [2]. The comparison of the experimental flow field results with the numerical results reveals the known numerical limits of secondary flow prediction regarding the extension and intensity [2].