| As traditional stator can hardly achieve the air deflection of finalstage stator in compressor, tandem cascade is usually used to realize it.Tangential displacement is a main parameter when blade profile and axialdisplacement are chosen, which affects the aerodynamic performancesignificantly at both design and off-design points. So, firstly, as DCA bladeprofile is chosen, numerical method is used to investigate the effects oftangential displacement on tandem cascade flow field and performance atboth design and off-design points; then, position (-10%,0.67) and(-10%,0.80) are chosen to taken into experimental investigation in lowspeed wind tunnel with TR-PIV at design point to capture and analyze thetime-averaged and temperory flow field both.Tandem cascades with different tangential displacement were takeninto numerical investigation at both high and low inlet Mach numberconditions to understand the aerodynamic performance and flow fieldeffects. The numerical results states, at design point, when tangentialdisplacement c/t is between0.80and0.83the tandem cascade would gainbetter aerodynamic performance with high Mach number of inlet, underthis situation rear blade flow topology were improved significantly, the gapinjection flow strength increased, which could decrease rear bladebourndary layer thickness; at off-design point, tandem cascade flow fieldperformance could gain good flow field and performance as incidence isbetween-11°and+4°.The results of high Mach number inlet simulationsagreed with the low Mach number inlet results well.Flow field in two kinds of tandem cascade which are position (-10%,0.67) and position (-10%,0.80) respectively is captured by TR-PIVsystem. And the time-averaged experimental results agreed with the highMach number numerical results well. Experimental results state thatposition (-10%,0.80) blades wake width was lower and shedding vortexwas smaller, its wake didn’t mix with the main stream flow too much thanthe other one. |
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