混合型前缘掠对离心压气机气动性能的影响

Effect of Hybrid Leading Edge Sweep on the Aerodynamic Performance of Small Scale Transonic Centrifugal Compressor

对带有叶片前缘混合掠的跨音速离心压气机流场进行了数值模拟研究.结果表明:叶片前缘混合前掠能够有效提高压气机流通能力,拓展失速裕度,推迟压气机失稳,使压气机工作裕度得到明显提升,而叶片前缘混合后掠则减少失速裕度,使压气机工作裕度下降,易发生失稳;叶片前缘混合前掠可以有效减弱叶轮通道内部激波强度,而前缘混合后掠会使通道内激波强度增强,造成一定的激波损失;虽然二者均可以改善通道下游分流叶片两侧低能流团的分布情况,但叶片前缘混合前掠改善作用更好;叶片前缘混合掠对压气机内部二次流的影响主要集中在叶片前缘附近,对叶轮出口附近二次流影响不大.通过对不同前缘混合掠结果对比分析,叶片前缘混合前掠在提高压气机流通能力、工作裕度以及改善内部气流流动情况具有明显的优势.

Four transonic compressors with hybrid swept blades were designed by a fully three-dimensional CFD technique,and numerical simulation was carried out to study the influence of hybrid swept leading edge on the flow field of compressors.Result shows that utilication of hybrid forward sweep blades improves flow capacity,extends stall margin,and reduces flow instability,bringing significant improvement of the compressor operation margin.On the contrary,the surge margin is reduced with the hybrid backward sweep blades.For the internal complex flow field,it is found that shock wave decreases significantly near the leading edge and shock wave moves to the upstream of channel by using the hybrid forward sweep blades,while shock wave is strengthened and shock loss increases due to the employment of hybrid backward sweep blades.Analyzing the internal flow of compressor channel shows that the distribution of low energy flow is improved for the splitter through both of swept compressor,in which the effect of forward sweep is much better.In general,the effect of hybrid leading edge sweep on the secondary flow concentrates on the blade leading edge,and there is small influence on the exit of impeller.Usage of hybrid forward sweep blades has an obvious effect on improving flow capacity,operating margin and internal flow.