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火焰面方法是求解非预混燃烧最有效的手段之一,但常规火焰面方程包含组分扩散系数相等及刘易斯数恒等于1的基本假设,所生成的火焰面库不适于层流非预混燃烧流场计算。针对单步全局化学反应及原子守恒两种混合分数定义存在的不足,采用守恒传输方程对混合分数重新进行了定义。然后根据物理平面层流对撞射流火焰控制方程及新混合分数定义,详细推导得出了考虑组分扩散系数及刘易斯数影响的相容火焰面方程。最后修正了TWOPNT软件包计算相容火焰面方程时影响计算稳定性及计算效率的三点不足,并通过仿真计算证实了相容火焰面方程的合理性,比较分析了火焰面方程的标量耗散率模型对火焰面库的影响。结果表明:相容火焰面方程与物理平面控制方程在新混合分数定义下生成的火焰面库比较吻合,而常规火焰面方程在火焰峰附近的温度分布,以及与单位刘易斯数差别较大的组分分布存在较大误差;当氧化剂密度与燃气密度比值及当量耗散率较小时,考虑密度变化的标量耗散率模型几乎不会对仿真结果产生影响。
The flame surface method is one of the most effective ways to solve the non-premixed combustion. However, the conventional flame surface equation contains the basic assumption that the diffusion coefficients of the components are equal and the Lewis’s number is equal to 1. The generated flame surface library is not suitable for laminar non-premixed Combustion flow field calculation. Aiming at the shortcomings of the definition of one-step global chemical reaction and atomic conservation, the mixed fraction is redefined by using the conservative transfer equation. Then according to the physical plane laminar flow confining jet flame control equation and the definition of new mixing fraction, the compatible flame surface equation considering the diffusion coefficient of component and the Lewis effect is deduced in detail. Finally, the three-point deficiencies that affect the calculation stability and computational efficiency when TWOFNT software package computes the compatible flame surface equation are modified. The rationality of the compatible flame surface equation is verified by simulation. The scalar dissipation of the flame surface equation Effect of rate model on flame surface database. The results show that the compatible flame surface equation is in good agreement with that of the physical plane control equation in the definition of the new mixed fraction, while the temperature distribution near the flame peak of the conventional flame surface equation and the group with the larger difference to the unit Lewis When the ratio of oxidant density to gas density and the equivalent dissipation rate are small, the model of scalar dissipation considering the variation of density has little effect on the simulation results.