串列叶片式离心叶轮内流场的数值研究

对串列叶片式离心叶轮内部三维可压缩湍流及气动性能进行了数值模拟,重点研究了诱导轮及导出轮之间5种不同相对周向位置排列方式对串列式叶轮内部流场及气动性能的影响,并与传统单列叶片式离心叶轮进行了比较.研究表明：对于串列式叶轮,相对周向位置因子对气动性能及流场的影响较大;当串列式叶轮的后轮相对于前轮沿旋转方向交错排列时,叶轮的多变效率低于单列式叶轮,当相对周向位置因子为0.0-0.4时,压比高于单列式叶轮,压比最大提高为1.4%,且叶轮出口流动参数沿周向分布比较均匀,对降低叶轮-扩压器间非定常冲击损失及气动噪声有利;当串列式叶轮的后轮以反旋转方向排列时,叶轮的多变效率及压比均低于单列式叶轮,且叶轮内部及出口流动分布很不均匀.研究成果对串列式离心叶轮及离心压缩机的节能设计具有一定的参考价值.

Numerical Study on Internal Flows in Centrifugal Tandem-Blade Impeller

Three-dimensional compressible turbulent flows and aerodynamic performance were numerically simulated for centrifugal tandem-blade impellers. The study was focused on the influence of relative circumferential arrangement configuration between the inducer and the exducer on the internal flows and aerodynamic performance of tandem-blade impellers. Five relative arrangement configurations were considered and the flows in tandem-blade impellers were compared with those in a conventional single row blade impeller. The numerical results indicate that, for the tandem-blade impeller, the relative circumferential arrangement configurations play important roles in the flow fields and aerodynamic performance. When the exducer is staggered with the inducer along the single rotation direction, the polytropic efficiency is lower than that of the single row blade impeller. When the factor of relative circumferential position lies from0. 0 to 0.4, the pressure ratio is higher than that of the single row blade impeller, and the highest pressure ratio increases by 1.4%. Moreorer, a relative smooth flow distribution along the circurrfferential direction forms at the impeller outlet, which may reduce the unsteady interaction between the impeller and the vaned diffuser and the aerodynamically generated noise sources there. When the exducer is staggered along the counter-rotation direction, both of the polytropic efficiency and the total pressure ratio of the tandem-blade impeller are lower than those of the single row blade impeller, and the outlet flow distributions vary quite along the circumferential direction.