中文摘要：

为了研究等离子射流的点火特性,建立了等离子射流在大气中扩展的二维轴对称非稳态可压流数学模型,采用Fluent软件对等离子射流扩展过程进行了数值模拟.获得了等离子射流扩展界面变化规律以及流场中静压、温度和速度分布特性.分析结果表明：等离子射流与大气间存在强烈的湍流掺混,掺混强度沿下游逐渐递增.喷嘴前9.2mm处出现驻定激波,激波后各参数随时间呈非单调变化;压力、温度和速度沿轴向及径向总体上呈衰减趋势;温度、压力等参数空间分布具有波动性;等离子射流扩展位移模拟值与实测值吻合较好.

英文摘要：

In order to study the properties of plasma jet ignition, two-dimensional-axisymmetric unsteady compressible mathematical model for plasma jet propagation in air was developed, and the software Fluent was used to simulate this process. The variation law of the interface between plasma jet and air was obtained as well as the distributions of static pressure, temperature and velocity of the plasma jet flow-filed. The analysis results indicate that., there occurs strong turbulent mixing between plasma jet and air; the mixing intensity increases along the downward flow-field gradually. There is a standing shock wave at 9.2 mm in front of the nozzle,and the pa- rameters of plasma jet behind the shock wave vary nonmonotonically with time. The pressure, temperature and velocity have the trend of attenuation along the axial direction and radial direction as a whole. The distributions of temperature,pressure,etc, fluctuate spatially. The dis- placement of plasma jet obtained by simulation agrees with that obtained by experiment well.