Analysis And Calculation Of The Loss Of Bowed Blade In Diffusion Cascade

With aero-engine advancing to the direction of high load, high thrust,compressor design system also advance. One-dimensional and S2stream surfacedesign method is widely used taking advantage of it short computational time andhigh precision. It has been proved that bowed blades can improve the performanceof compressor. In this paper, by means of the numerical simulation, use NACA65series cascade to analyze the cascade loss and the influence of bowed blade onperformance of diffusion cascade.First, confirm the numerical calculation method based on experimental data.Calculate the two-dimensional cascade of NACA65sreies in different geometry inletAngle, blade turning Angle, cascade solidity inflow Mach number. It proves thatincidence, deviation and loss have similar change, using the results of numericalcalculation results and the empirical formula, modify the empirical formula, whichcan quantitative describe the profile loss.Second, calculate the two-dimensional cascade of NACA65sreies in the sameboundary conditions. It found that turning Angle increasing lead to the largersecondary flow loss. Under40°angle, separated flow hold significantly wholeheight. Cascade solidity mainly causes increasing of profile loss, while aspect ratioincreasing lead to reduce of secondary flow loss. Curve the blade40tuning angle Itresulted that positive bowed blade made the saddle point move to the pressure side,a small separation bubble near the leading edge on the suction surface delayed theseparation, and enhanced the "C" type pressure distribution trend on suction surface;and reduced secondary flow loss, and enhance flow ability in end wall area. negativebowed blade has opposite influence.Finally, by simulated1.5stages of compressor in which the stator was bowedblade. It proved that bow blade improved the performance of the1.5stage up to1.634%, especially in the near end wall corner, the efficiency increased significantly.After bowing the blade, the flow field distributed again. It increases the capacity ofradial migration, negative the flow migration, reduced the flow separation onsuction surface corner and enhanced the flow ability through end wall. Bowed bladecould reduce the secondary flow and decrease the total pressure loss in a certainrange of angle and height.