离心压气机非定常流动频域特性

以涡轮增压器56 mm离心压气机为研究对象,采用定常流动求解方法,对其三种不同转速下的工作特性进行了预测并与实验进行了对比分析;应用相延迟方法,对高转速近失速点工况下压气机内部的三维非定常流动进行了数值模拟及频谱分析,对叶轮流道、无叶扩压器以及蜗壳内的流动频谱特性进行了初步分析.频域分析表明,对于本文所研究的离心压气机,非定常脉动特性主要表现在叶轮流道中,是诱发压气机气动噪声的主要因素,而在蜗壳内,非定常脉动特性显著减弱.

CHARACTERISTICS OF UNSTEADY FLOW IN FREQUENCY DOMAIN IN A CENTRIFUGAL COMPRESSOR

Performances prediction using steady RANS solver and validation are performed on a 56 mm turbocharger compressor under three working speed-line in this paper.Unsteady flow simulation in near-surge condition at a high rotation speed is then carried out and frequency-amplitude characteristics in an impeller,vaneless diffuser and volute are studied.Results show that unsteady effect lies mainly in an impeller and is the main reason for inducing aero-acoustics in a centrifugal compressor,while in the volute,unsteady effects decrease significantly and has less contribution to acoustics level.