Influence of Turbulent Flow Characteristics and Coherent Vortices on the Pressure Recovery of Annular Diffusers: Part B — Scale-Resolving Simulations
Influence of Turbulent Flow Characteristics and Coherent Vortices on the Pressure Recovery of Annular Diffusers: Part B — Scale-Resolving Simulations
复制标题
湍流特性和相干涡流对环形扩压器压力恢复的影响：B 部分 - 尺度解析模拟
DOI：
10.1115/gt2015-42477
复制
发表时间：
2015
影响因子：
2.8
通讯作者：
J. Seume
中科院分区：
文献类型：
--
作者：
Bastian Drechsel;C. Müller;Florian Herbst;J. Seume
本文研究了考虑涡轮出口条件的扩散流。该装置由低速轴向扩压器试验台组成，该试验台代表1/10比例的重型排气扩压器，具有环形和锥形扩压器部分。本文A部分通过实验研究表明，湍流动能和雷诺剪应力是影响扩散器压力恢复的相关物理参数。为了补充实验研究，采用SST-SAS湍流模型进行了非定常尺度解析CFD模拟。首先，利用实验数据对扩散器的积分参数和局部流动特性进行了验证。第二步，利用经过验证的SST-SAS结果，分析了转子与扩散器边界层产生的相干涡的相互作用。研究发现，这些涡对旋翼下游区域和扩压器入口的边界层分离有重要影响。ASME版权所有©2015
This paper examines the diffuser flow with consideration to turbine outflow conditions. The setup consists of a low-speed axial diffuser test rig, that represents a 1/10 scaled heavy-duty exhaust diffuser with an annular and a conical diffuser part. In part A of this paper it was shown through experimental investigation that the turbulent kinetic energy as well as the Reynolds shear stresses are the relevant physical parameters that correlate with diffuser pressure recovery. To complement the experimental investigations, unsteady scale-resolving CFD simulations are performed, applying the SST-SAS turbulence model. As a first step, the numerical approach is validated by means of the experimental data with regards to the diffuser’s integral parameters as well as the prediction of local flow characteristics. In a second step, the interaction of coherent vortices generated by the rotor and the diffuser’s boundary layer are analyzed by means of the validated SST-SAS results. These vortices are found to have a major impact on the boundary layer separation in the region immediately downstream of the rotor and at the diffuser inlet.Copyright © 2015 by ASME