前、后排叶片相对位置对串列转子性能的影响

在折合叶尖切线速度381m/s条件下,利用跨声串列转子技术实现了总压比2.25,负荷系数高达0.55的风扇转子设计。基于数值模拟结果,分析了串列转子前、后排叶片周向和轴向几何相对位置的变化对各自其整体性能的影响及原因。研究结果表明:前、后排几何相对位置的变化改变了后排叶片堵塞系数及其进、出的轴向速度和气流角,因而改变了速度三角形,导致了串列转子整体及各排叶片速度三角形及特性的变化;对于前、后排叶片最佳几何相对位置的选择,当后排叶片在前排叶片弦向上有0.1～0.15倍弦长的重叠时、后排叶片在周向上较为靠近前排叶片压力面时,串列转子能够获得较高的气动性能。

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.