步长对激光点火一维模拟的影响

从激光点火的热机理出发，通过对一维有限差分模型的模拟和计算，分析了时间步长(△t)和空间步长(△x)对点火能量阈值及点火延迟时间的影响。结果表明，点火能量阈值在一定范围内只与△x有关，而与△t无关。△x一定时，点火延迟时间随着△t的增大而缓慢增加。当人射激光能量接近点火能量阈值时，点火延迟时间基本上不随△t变化而变化，但△x＞2．5×10

Effect of Step on One-Dimensional Simulation of Laser Ignition

Proceeded from the thermal mechanism of laser ignition, effects of time step (△x) and space step (△x) on ignition threshold and igniting delay time,based on the simulations and calculations of a onedimensional finite difference model, were analyzed. Results showed that within a definite range,ignition threshold merely related to △x but not △t. If △x was changeless, igniting delay time increased tardily along with △t. However, igniting delay time didn＇t vary with △t by and large when laser energy approached the ignition threshold ,but △t affected ignitingdelay time greatly when △x was more than 2.5 X 10-5m. If △t was changeless,igniting delay time had a approximatively linear add along with △x when laser energy was more than the ignition threshold,while igniting delay time had a cubic curvilinear add along with △x when laser energy approached the ignition threshold.