超声速湍流燃烧的有限速率源项封闭方法

Finite Rate Closure Method of Chemical Source Term in Supersonic Turbulent Combustion

为了发展超声速湍流燃烧中化学反应源项的封闭方法,更精确地模拟湍流燃烧相互作用,引入两类化学反应有限速率模型:PaSR(Partially Stirred Reactor)模型及其可压缩性修正模型(C-PaSR),并用于德国宇航研究中心(DLR)的氢燃料超燃冲压发动机燃烧室的数值模拟。计算结果显示,支板后形成的抬举火焰在剪切层产物回流和喷氢的共同作用下稳定在支板后1~2倍支板高度的位置,流场结构与实验纹影符合较好。引入模型后的不同截面的温度和轴向速度均有所改善,特别是较远处温度场与实验结果吻合非常好。C-PaSR模型的预测结果比PaSR模型略有改善。通过化学反应源项修正系数分析了流场各处燃烧和混合的特征时间尺度相对大小,有利于理解湍流燃烧相互作用的过程。

In order to consider the interaction between turbulence and combustion in the closure of chemical source term in supersonic turbulent combustion,two finite rate methods,Pa SR（Partially Stirred Reactor）model and its compressible modified（C-PaSR）model were used to simulate the supersonic combustion flowfield in German Aerospace Center（DLR）scramjet combustor model. Because of the recirculation of products in shear layer and the hydrogen injection,a lifted flame was fixed behind the strut for one to two times height of it. With the methods,parameters like velocity and temperature showed better agreement with experiment results at three different sections,especially far from the injector. Results from case with the C-PaSR model were to some extent better than that with the PaSR model. The domination between chemical time scale and turbulent time scale in the flowfield were analyzed according to the modified chemical source term coefficient. It helped to investigate the turbulence combustion interaction.