Relationship Between Optimum Curved Blade Generate Line and Cascade Parameters in Subsonic Axial Compressor

Abstract

Curved blade has been widely used to reduce the endwall loss, but there is no criterion for curved blade design. Relationship of the optimum curved blade generate line (stack line) and the inlet Mach number, solidity, aspect ratio and camber angle in a linear compressor cascade were researched by optimization method in present paper. The stack line is vertically symmetrical, composed of two third-order Bezier curves and a straight line. The results show that total pressure loss coefficient decreases with the curved height increasing in the present calculate conditions at the same curved angle, and the optimum curved height is 0.5. The total pressure loss coefficient variation with curved angle presents a approximate parabola line type at the same curved height, there is an optimum curved angle, at which the total pressure loss coefficient is minimal. The optimum curved angle variation with the cascade parameters. Optimum curved angle increases with the inlet Ma and camber angle increasing, optimum curved angle variation with inlet Ma shows a polynomial curve type, optimum curved angle varied linearly with camber angle increasing. Optimum curved angle has little changes with solidity and aspect ratio increasing, optimum curved angle is about 6.5° in present conditions, but optimum curved angle will change with the blade loading. The benefit of the optimum curved blade increases with the inlet Mach number and camber angle increasing, and it has little change with solidity and aspect ratio increasing.