Effects of Relative Geometry Position of Forward and Aft Blades on Performance of Tandem Rotor

With transonic tandem rotor technology,fan stage rotor was accomplished,which produced total pressure ratio of 2.25 and responding loading coefficient(ψ=ΔH*/U2tip) of 0.55 at corrected tip speed of 381m/s.Based on the simulation results,the relative circumferential and axial position from forward blade to aft blade was analyzed in terms of the aerodynamic influence on tandem rotor performance and flow mechanism.The result indicates that the relative geometry position has great impact on blockage factor of aft blade as well as its axial velocity and relative flow angle at the inlet and outlet section,which changed the velocity triangle and results in the performance change of tandem rotor and respective blades.For the optimum choice of relative geometry,the tandem rotor would attain higher performance if there is 0.1~0.15 chord length overlap at chord-wise direction of forward blade and aft blade is closer to the forward blades pressure side.