中文摘要：

在材料表面改性新技术——冷喷涂工艺中，喷嘴出口射流流场的特性对喷涂介质参数、涂层性质有重要影响．为此通过适当的工程简化，以不同材料、直径的固体颗粒，对圆喷嘴超音速流场进行了两相射流流场的数值模拟计算，得到了流场的压力和速度分布．结果表明：大密度颗粒与大直径颗粒受流场影响趋势相同；材料密度较大时，颗粒直径应相对取小，材料密度较小时，颗粒直径应相对取大些，喷涂效果最佳；若喷涂气体为空气时，最佳颗粒直径应在1～10μm．

英文摘要：

In the cold spray technology for material modification, the two-phase jet flow at outlet of nozzle is an important part that influences the spray parameters and coating layer properties. Based on reasonable simplifications, the supersonic jet flow field of round nozzle is simulated by different materials and diameters of particles. The distribution of pressure and velocity of the flow field is acquired. The experiment can be optimized by these results： the pellets with great density or with big diameter have the same influence tendency. When the material density is great, the pellet diameter should be taken short relatively, when the material density is small, the pellet diameter should be taken long relatively, the modification effect is best. If spray gas is air, the best pellet diameter should be taken between 1μm and 10 μm.