超声速燃烧数值模拟中的湍流与化学反应相互作用模型

高精度数值模拟有助于理解超声速湍流燃烧中湍流与化学反应的相互作用,可为发动机燃烧室等工程应用设计提供可靠的预测模型。除直接数值模拟外,目前在湍流燃烧应用中使用的大涡模拟和雷诺平均Navier-Stokes模拟均需要借助模型模化发生在湍流小尺度上的流动与化学反应过程对湍流大尺度运动的影响。现有的湍流与化学反应相互作用模型大致可分为:火焰面类模型和概率密度函数类模型,2类模型在不同的应用中各自具有优势和局限性。此外,现有模型大都基于低马赫数燃烧,而超声速燃烧中通常会伴随快速混合、局部熄火和再着火以及激波等复杂过程,这为发展其中的湍流与化学反应相互作用模型提出了更多的挑战。

Modeling of turbulence-chemistry interactions in numerical simulations of supersonic combustion

The high-fidelity numerical simulation is considered as a useful approach to understand the turbulence-chemistry interactions in supersonic turbulent combustion and it can be used as a predictive model for engine design in engineering applications. In numerical simulations, large-eddy simulation and Reynolds averaged Navier-Stokes simulation require to model the effects of the motion and chemical reactions at small scales on large scale motions. The existing turbulence-chemistry interaction models can be classified into two types: the flamelet-like model and the probability density function model. Both types have their own advantages and weaknesses in different applications. In addition, most of the existing models are based on low-Mach-number combustion, while the supersonic combustion involves more complex processes such as rapid mixing, local extinctions/re-ignitions and shock waves, which pose significant challenges to the modeling of turbulence-chemistry interactions.