Experimental study of end-wall flow in a compressor cascade

Experimental measurement of the variations of flow velocity and flow angle within the blade passage of a linear compressor cascade and the loss distribution at its outlet section are presented in this paper. The results are measured by means of a miniature multielement pneumatic probe. With the aid of flow visualization and the measurements of various flow quantities, it is observed that flow separation occurs in the corner between the end wall and suction surface of the blade and that the separation region increases with increased incidence. A loss core mainly attributed to the corner stall forms. The loss core region for 10-deg incidence is correspondingly larger than that for 0-deg incidence. The secondary vortices and corner separations make the stream surfaces warped and twisted rather strongly, even in a compressor cascade. The comparison between the measured outlet angles and those calculated with an inviscid secondary flow approximation shows quite similar trends, but the relatively large size and the complex structure of the corner separation require more accurate experimental work and additional theoretical considerations.