Abstract: A mathematical model is presented to describe the fluid flow, the electromagnetic, heat flow phenomena in an arc plasma torch we constructed．A computing program has been developed to simulate the different factors that influence on the thermal efficiency．The results show that the thermal efficiency of the torch increases with the increase of the gas flow rate, the nitrogen or hydrogen content and decrease of the length of torch．The current and diameter of the torch have no obvious effects on the thermal efficiency．

Key words: Plasma spray, Numerical simulation, Thermal efficiency

摘要： 利用计算机模拟技术，采用有限容积方法，针对自制的低能耗、高效率内送粉等离子喷涂设备，对喷枪内部影响喷涂热效率的因素进行了分析。研究结果表明通过适当提高进气流量、提高混合气体中的氮气或氢气含量和减少喷枪通道长度，均能提高等离子喷枪热效率。而电流的大小以及喷枪的通道直径对热效率无显著影响。

关键词: 等离子喷涂, 数值模拟, 热效率