Improvement of Compressor Blade Leading Edge Design

The effect of compressor blade leading edge shape on the blade performance was investigated numerically.It is found that the flow experiences rapid expansion around the traditional circular leading edge right downstream of the stagnation point,and causes overexpanding at the leading edge suction surface.An adverse pressure gradient emerges at the blending point of the leading edge with the main blade surface due to the curvature discontinuity.The adverse pressure gradient often causes a laminar separation,if the Reynolds number and turbulence levels of inlet flow are low.The elliptical leading edge has a smooth curvature distribution,which suppresses the overexpansion and causes a weak adverse pressure gradient,so that the blade with elliptical leading edge has a better performance.But the elliptical leading edge is difficult and expensive to manufacture.The circular leading edges with flats are suggested,which have typical Cp structure of multiple weak suction peaks at the edges of the flats instead of a single strong suction peak in the case of the conventional circular leading edge.For most cases,the leading edge with one flat can improve the blade performance no less than the more complicated elliptic (a/b =2) one,and can be manufactured easily.