丙烷/空气低温等离子体点火起爆数值研究

Numerical Simulation Analysis for Low Temperature Plasma Ignition of Propane/Air

为研究脉冲爆震发动机低温等离子体点火起爆机理,充分考虑丙烷/空气详细化学反应动力学机理,将低温等离子体点火器放电区等效为高温高压热核,利用FLUENT软件内置的层流有限速率化学反应模型,对脉冲爆震发动机低温等离子体点火后由缓燃转爆震(DDT)的过程进行模拟,并对该过程进行详细分析。实验结果表明,将低温等离子体点火器简化成一定压力和温度的火核进行数值模拟是可行的,压力接近常压,壁面温度为常温更合理。数值模拟的爆震波发展时间小于实验结果,考虑到实验时有点火延迟和测量误差,可以认为实验值符合数值模拟时火核为常压、壁温为常温的计算结果。

In order to study the initiate mechanism of pulse detonation engine ignited by low temperature plasma through numerical simulation method, the low temperature plasma ignition discharge area was simplified into heat kernel with high temperature and high pressure considering the propane/air chemical reaction kinetics mechanism. The laminar finite-rate model in the FLUENT was used to simulate the combustion process from deflagration to detonation transition（DDT） initiated by low temperature plasma, and the process was analyzed minutely. The experimental results show that it is feasible to simplify the low temperature plasma ignition to the fire kernel of a certain pressure and temperature in numerical simulation under a reasonable boundary condition that the pressure is atmospheric pressure and the wall temperature is normal temperature. The ignition delay and measurement error results in that the detonation wave development time of the numerical simulation is shorter than that of experimental result. The measurement value of the experiment is close to the result in numerical simulation under the condition of normal pressure heat kernel and normal temperature wall.