基于旋转爆震三维流场结构分析的计算模型对比研究

Computational Models Based on Analysis of Three Dimensional Flow Field Structures in Rotating Detonation

关键词:  燃烧室  旋转爆震  三维  计算模型  流场结构  传播特性  推力性能

Key words:  Combustor  Rotating detonation  Three-dimensional  Numerical model  Flow structures  Propagation characteristics  Thrust performance

摘要:

为了研究不同计算模型对三维旋转爆震数值模拟的影响，分别基于Euler方程、N-S方程、RANS方法和IDDES方法并结合滑移、无滑移壁面边界条件，耦合氢气/空气的有限化学反应速率模型（7组分8基元反应），采用高分辨率的五阶有限差分格式WENO-PPM5离散对流项，对圆环筒型燃烧室内的三维旋转爆震波进行数值模拟，得到了不同模型下旋转爆震波的流场结构、传播特性和推力性能。对比了不同计算模型对流场结构的影响。当采用滑移壁面边界条件时，Euler方程和N-S方程的计算结果较为一致。当使用无滑移壁面边界条件时，边界层的存在会导致可燃混气与燃烧产物之间接触面上的爆燃燃烧区域沿壁面向上游渗透，增大爆燃区域的范围；且爆震波锋面非受限侧变窄、严重变形，不同计算方法计算的变形程度有所不同。

Abstract:

The effects of numerical model on three-dimensional rotating detonation in an annular chamber are investigated by using different models including Euler， Navier-Stokes（N-S） and Reynolds-Averaged N-S（RANS）， Improved Delayed Detached-Eddy- Simulation（IDDES） and different wall boundary conditions including slip wall and non-slip wall. The chemical sources are evaluated by 7-species-and-8-reaction finite-rate chemical reaction model of hydrogen/air mixtures， and the convection terms are discretized by a fifth order WENO-type scheme with high resolution， namely WENO-PPM5. The three-dimensional rotating detonation wave in an annular chamber is simulated. And the flow structure， propagation property and propulsion performance are obtained. Comparisons of flow structure are made among the results of different numerical models. When using slip wall condition， the results of Euler and N-S are very similar. While considering non-slip wall condition， the existence of boundary layer leads the deflagration at the interface between reactant and product extending to upstream along the wall， and enlarges the range of deflagration zone. Besides， the unbounded side of detonation front becomes narrow and appears serve deformation. The deformation degrees show some difference in different computational methods.