径向双旋流燃烧室流场结构大涡模拟研究

Large Eddy Simulation of Aeroengine Combustor with Counter-Rotating Swirler

关键词:  航空发动机  燃烧室  径向双旋流  大涡模拟  动态亚网格模型

Key words:  Aeroengine  Combustor  Counter-swirler  Large eddy simulation  Dynamic smagorinsky model

摘要:

为深入了解真实航空发动机燃烧室内流场结构，在自有CFD平台上采用动态亚网格湍流模型对一种径向双旋流环形燃烧室的单个头部构型冷态流场进行了大涡模拟。为保证模拟精度，没有对模型进行常规简化处理，对包括全部气膜冷却小孔在内的所有精细结构均进行了完全仿真。计算验证了程序对高度复杂流场的模拟能力，结果表明，大涡模拟能较为全面地反映燃烧室内复杂流场从静止启动到统计定常的非定常发展过程，并成功捕捉到流场中心回流区等各种大尺度结构及涡旋破碎泡等旋流特征；大涡模拟所获得的时间平均流场结构与已有PIV试验结果定性一致，与RANS计算相比更接近试验测量值。

Abstract:

To gain an improved understanding of the flow and turbulence structures in practical aeroengine combustor，large eddy simulation with dynamic Smagorinsky sub-grid model was used to explore the complex flow field in a single sector of a typical aeroengine combustor with counter-rotating swirler. The complex geometric configuration including all film cooling holes was fully simulated without any conventional simplification in order to reduce the modeling errors. The capability of our CFD code to simulate very complicated flow was validated by the calculation. The unsteady process that turbulent swirling flow developing from static to statistically stationary status was totally reproduced. Large-scale coherent structures like central recirculation zone(CRZ) and swirling flow characteristics like vortex breakdown were well captured. Time-averaged flow field predicted by LES shows qualitative agreement with PIV measurement and performed better than RANS.