喷嘴出口与基板间距离对冷喷涂超音速流场的影响  

Effects of standoff distance on the supersonic flow fields in cold gas dynamic spraying

作　　者：张宇军[1] 梁永立[1] 张俊宝[1] 

机构地区：[1]宝山钢铁股份有限公司研究院,上海201900

出　　处：《宝钢技术》2011年第5期30-36,共7页Baosteel Technology

摘　　要：采用计算流体力学(CFD)模拟研究了冷气动力喷涂技术中喷嘴出口与基板距离(SoD)对超音速流场(包括气体流场和粒子流流场)的影响,通过计算流场的分布特性,分析了流场中速度、温度、压力和密度的变化规律。模拟结果发现,由于基体前激波的存在,极大影响了气体和粒子流流场。气流形成连续交替的膨胀波、压缩波波系,在马赫盘处气体速度达到超声速,越过马赫盘以后速度下降很大。SoD为40 mm时,1μm粒子流流场达到最优;SoD为50 mm时,5μm和22μm粒子流流场达到最优,此时粒子流对基体的轰击速度最大。The effects of standoff distance（SoD） on the supersonic flow fields（including gas and particle flow fields） during cold gas dynamic spraying（CGDS） are investigated by means of computational fluid dynamics（CFD）.The variation of velocity,temperature,pressure and density with different SoD is elucidated through the analysis of the distribution properties of the flow fields.It is found that the shock waves in front of the substrate remarkably influence the gas and particle flow fields.The system of expansion waves and pressure waves was caused by the gas flow.The velocity of the gas reaches the supersonic at the position of the Mach disc,while it decreases sharply when the gas flow crosses the Mach disc.The optimal SoDs are 40 mm for 1 μm particles and 50 mm for both 5 μm and 22 μm particles.At the moment,the bombardment velocity of the particle flow to the substrate will be the maximum.

关 键 词：冷气动力喷涂 喷嘴出口与基板间距离 数值模拟 

分 类 号：TG174.442[金属学及工艺—金属表面处理]