建立了氩气-氢气等离子射流在空气中流动、传热的三维数学模型, 基于计算流体动力学Fluent软件, 运用SIMPLE算法求解控制方程, 使用标准κ-ε湍流模型结合组合扩散系数法, 模拟了自由等离子射流和平板基底情况下等离子射流各区域的温度、速度和湍动能分布。结果表明: 平板基底对射流上游区域影响较小, 但在基底附近区域速度、温度及组分浓度均沿基底表面向周围铺开; 基底对射流速度的影响大于其对温度的影响, 距离基底15 mm处速度开始偏离自由射流, 并逐渐减小为0, 而温度在距离基底5 mm处开始偏离自由射流下降至600 K; 基底附近的压力分布导致基底前端速度沿径向呈“驼峰”状分布, 出现对称的速度极大值。

Based the computational fluid dynamic software Fluent, a 3D numerical model including heat transfer and flow of Ar-H2 plasma jet in air was built, and the governing equations were solved by using SIMPLE algorithm, standard κ-ε model and combined-diffusion-coefficient method were used to simulate the distribution of temperature, velocity and turbulent kinetic energy for free jet and plasma jet with substrate. The results show that the substrate had fair little effects on upstream region of jet, but the velocity, temperature and composition near substrate zone spread along substrate surface to the around. The effect of substrate on the jet velocity was more than that on temperature, the velocity started deviating from free-jet at 15 mm from substrate and gradually reduced to 0, and the temperature started deviating from free jet at 5 mm from substrate and decreased to 600 K. The pressure distribution near substrate exhibited "camel-hump" shape, and the symmetrical maximal velocity value appeared.