Computational analysis of nozzle geometry variations for subsonic turbulent jets
Computational analysis of nozzle geometry variations for subsonic turbulent jets
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DOI：
10.1016/j.compfluid.2016.05.033
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发表时间：
2016-09
影响因子：
2.8
通讯作者：
M. Çetin;Vitali Pauz;M. Meinke;M. Meinke;W. Schröder;W. Schröder
中科院分区：
文献类型：
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作者：
M. Çetin;Vitali Pauz;M. Meinke;M. Meinke;W. Schröder;W. Schröder
对雷诺数Re= 7.5× 105、马赫数M= 0.341的直升机发动机喷管结构的湍流热射流进行了大涡模拟。数值方法是基于分层细化笛卡尔网格。喷管壁面边界采用保守割元法求解。三个喷嘴的几何形状越来越复杂，即，一个干净的几何形状没有任何内置的组件，喷嘴与中心体，喷嘴与中心体加支柱的流场计算。数值方法验证了一个单一的解决方案，同轴，和人字形喷嘴射流问题。网格收敛研究表明，由于喷嘴几何形状的复杂性，基本的流动特性得到了很好的解决。结果表明，出口下游35个喷嘴半径区域的流场主要由几何形状引起的流动结构所控制。与干净的几何形状相比，其他两种配置显示出增强的湍流混合。中心体和中心体加支杆喷管构型在近喷管出口区ST = 0.15处显示出一个谱峰，这是由中心体的尾流引起的。
Large-eddy simulations (LES) of turbulent hot jets emanating from realistic helicopter engine nozzle configurations at a Reynolds number of Re= 7.5× 10 5 and a Mach number of M= 0.341 are conducted. The numerical method is based on hierarchically refined Cartesian meshes. The nozzle wall boundaries are resolved by a conservative cut-cell method. Three nozzle geometries of increasing complexity are considered, ie, the flow fields of a clean geometry without any built-in components, a nozzle with a centerbody, and a nozzle with a centerbody plus struts are computed. The numerical method is validated by solutions for a single, a coaxial, and a chevron nozzle jet problem. A grid convergence study shows that the essential flow characteristics due to the intricacy of the nozzle geometry are well resolved. The results evidence that the flow field in the region 35 nozzle radii downstream of the exit is dominated by flow structures induced by the geometry. Compared to the clean geometry, the other two configurations show enhanced turbulent mixing. The centerbody and centerbody-plus-strut nozzle configurations reveal a spectral peak in the near nozzle exit region at S t= 0.15 which is caused by the wake flow of the centerbody.