超音速混合层着火距离的一种理论预测方法

A theoretical prediction method of ignition distance in supersonic mixing layer

提出了超音速混合层着火距离的一种理论预测方法。基于超音速混合层来流热力学参数和考虑粘性加热及可压缩性效应的修正温度,定义了密闭容器反应系统。耦合详细化学反应机理获得该系统的着火延迟时间,并基于超音速混合层的平均流动速度获得了着火距离。其预测结果与高精度数值模拟结果相符,同时该理论预测方法能够从物理上很清晰地解释已有研究中所观察到的着火距离随相关影响因素的变化规律。同时,该预测方法为定性认识超音速着火距离及其变化规律提供了简易可行的途径,为耦合有限试验和数值模拟结果实现着火距离的定量预测提供了理论支撑。

A theoretical method is proposed for the prediction of the ignition distances in the supersonic mixing layer. Based on the inlet thermodynamics parameters and the correction temperature related to viscous heating and compressibility effect, a closed container reaction system is defined. The ignition delay time of the closed container reaction system are obtained through coupling the detailed chemical reaction mechanism. The ignition distance is got according to the mean flow velocity of the supersonic mixing layer. The ignition distances obtained by the theoretical prediction method agree well with those by CFD. The variation of the ignition distances with the related influence factors, which is observed in the previous studies, can be clearly explained in physics by the present theoretical prediction method. Besides, the theoretical prediction method for the ignition distance is a simple way for the qualitative understanding of the supersonic ignition distance and its variation rule, and also provides a theoretical basis for the implementation of quantitative prediction of ignition distance through coupling the limited experimental results with numerical simulation ones.