Numerical evaluation of transient flow characteristics in a transonic centrifugal compressor with vaned diffuser
Numerical evaluation of transient flow characteristics in a transonic centrifugal compressor with vaned diffuser
复制标题
DOI：
10.1016/j.ast.2017.08.003
复制
发表时间：
2017-11
影响因子：
5.6
通讯作者：
A. Zamiri;Byungju Lee;J. Chung
中科院分区：
文献类型：
--
作者：
A. Zamiri;Byungju Lee;J. Chung
采用三维可压缩非定常Navier-Stokes方程对一台高压缩比跨音速离心压气机的流场进行了数值模拟。计算域由一个进口喇叭口和一个带分流叶片的叶轮组成，后面是一个二维楔形叶片扩压器。通过压气机气动性能和压气机通道内流场的计算结果与实验结果的对比，验证了数值方法的有效性。对叶轮和扩压器通道内的瞬时流场和时均流场进行了详细的分析。本研究的重点是在压气机设计点的叶轮和扩压器通道内的压力波动和熵产生。结果表明，叶轮和扩压器叶片之间的相互作用导致界面区域的非定常性和扩压器通道内的脉动行为。由叶轮-扩压器相互作用和伪周期非定常分离气泡产生的具有不同对流速度的压力波在时间/空间域中沿扩压器叶片表面沿着捕获。通过对压力脉动频谱的分析，研究了离心压缩机叶片通过频率噪声的主要来源--压力脉动频谱的噪声特性。目前的非定常雷诺平均纳维尔-斯托克斯（URANS）方法可以作为一种工具，用于预测非定常流动和压气机噪声特性，并采用适当的湍流模型和高分辨率网格。
Three-dimensional, compressible, unsteady Navier–Stokes equations are solved to investigate the flow field of a transonic centrifugal compressor with high compression ratio. The computational domain is consisted of an inlet bell mouth and an impeller with splitter blades, followed by a two-dimensional wedge vaned diffuser. The numerical method was validated by comparing the results with those of experiments in terms of aerodynamic compressor performance and flow field within the compressor passages. A detailed analysis of instantaneous and time-averaged flow field was conducted in the impeller and diffuser passages. The present study focuses on the pressure fluctuations and entropy production within the impeller and diffuser passages at the compressor design point. It is shown that the interaction between the impeller and diffuser blades leads to unsteadiness at the interface region and a pulsating behavior within the diffuser passages. Pressure waves with different convective velocities, generated by the impeller–diffuser interaction and pseudo-periodic unsteady separation bubbles, are captured in the time/space domain along the diffuser blade surfaces. The pressure fluctuation spectra were evaluated to analyze the noise characteristics of the centrifugal compressor as the main source of blade passing frequency noise. It is expected that the current unsteady Reynolds-Averaged Navier–Stokes (URANS) approach can be used as a tool for the prediction of unsteady flow and compressor noise characteristics with a proper turbulence model and well-resolved grids.