The Influence Of Leading-Edge Geometry On Aerodynamics Of High Lift Compressor Cascades

The concept of High-lift compressor airfoil,obtaining the benefits of higher single-stage loading and less blades,is the focus of compressor design.In high lift compressor cascades,suction boundary layer encounter stronger adverse pressure gradient,and much more easy to separate from the surface.The method to con-trol the separation has been deeply researched for high lift low pressure turbine ,but there is very little published research on influence of leading-edge for three dimensional flow in high-lift compressor cascades. The thesis present detailed ex-periment results and CFD analysis on the aerodynamic influence of leading-edge geometry variation for two high-lift compressor airfoils:a circular arc airfoil and a elliptic arc airfoil with a ratio 3:1. The experiments conducted on a large scale ,low-speed linear cascade tunnel. Detailed flow field measurements were made us-ing three-and seven-holes probes and static pressure distributions were measured by resin-based printed airfoils,at a range with considerably low Reynolds number and low Free-Stream Turbulence Intensity.All measurements were made at de-sign incidence,0°.The thesis is consists of three major discussion on leading-edge geometry caused aerodynamic change,with the tip leakage absence:1. The boundary layer performance of high-lift compressor cascades.Detailed numerical simulations were made based on two CDA high-lift compressor airfoil with different leading-edge geometry. By analysing the influence of leading-edge geometry on suction surface boundary,especially concern the flow separation and transition at leading-edge section,then the influence of Re and FSTI parameters were discussed.2. The influence of leading-edge geometry on profile loss.Measurements based on high-precision three-hole probes and surface static pressure distribution were made,the profile loss at different flow condition were discussed.3. The influence of leading-edge geometry on compressor cascades aerodynam-ics. Outletplane flow field was measured by seven-holes probe, and surface flow visualization experiment gives a direct view of suction and endwall flow.This section discussed the leading-edge geometry variation on three-dimensional flow in cascades and aerodynamic loss of the blades.