Research On The Effect Of Serrated Trailing Edge Of Stator On A Low Speed Axial Compressor

AOA of downstream blade row can be changed using modification of serrated trailing edge by which streamwise vortices are generated and the blending of wake shear layer and mainstream is strengthened,making it a potential passive control technique to extend the stall margin of compressor.The effect of serrated trailing edge of stator on a multi-stage low speed compressor was researched in the paper.Detached Eddy Simulation was adopted when computing subsonic serrated plane cascades,the result shows that: Detached vortices will be cut and split under positive AOAs during which hairpin vortices are generated beside the serrations;Under a negative AOA,however,intensity and shedding frequencies of the vortexes are changed due to the potential interference of STE.Further investigation shows that narrow STE has better performance than wide STE as a whole and the improvement of wake deficit closely interrelates with AOA as well as the influence to vortexes exerted by the STE.Research about effects of serrated stator on a 2.5 stage low speed compressor was also performed,the result shows that :In near stall state,the first modification improves the pressure rise coefficient of the first stage while maintain nearly the same total pressure loss coefficient,yet the performance of second stage declines substantially;declining first stage performance though,the second modification fairly cuts the total pressure loss coefficient and promotes pressure rise coefficient partly.The second modification is worse in declining compressor performance than the first one,but it does extend the stall margin of the compressor which may be interrelated with the improvement of the clearance flow pattern.Comparation between the plane cascade and a real compressor was also made,it shows that there is some difference concerning serration effects between them.Only part of flow patterns between the plane cascade serrations are inherited by the real compressor which causes disagreement between their total pressure coefficient,and influence to downstream AOA is not obvious.