小功率等离子体射流的流特性

采用焓探针对小功率(5kW)热喷涂等离子体射流的焓、温度和速度进行了测量和计算。研究了气体成分、流量、电弧电压和电流对等离子流体的焓、温度和速度分布的影响。结果表明，对于单一氩气等离子体，当使用新喷嘴时，增大氩气流量能够使喷嘴内部电弧弧根向出口方向移动，从而增加等离子体射流的焓、温度和速度。对于Ar-N2等离子体，增加气体中氮气的含量，会提高等离子电弧电压，在同样的输入功率下，改变等离子电流和电压对等离子体的焓、温度和速度影响较小。对于Ar-N2等离子体，增加氢气含量会明显地提高等离子射流的速度和热传递。

Flow characteristics of a low power plasma jet

The effect of plasma gas composition,flow,arc current and voltage on the enthalpy,temperature and velocity of plasma jet in the arc field free region has been investigated at input power of 5kW using an enthalpy probe.The results show that increase of the argon gas flow rate increases the plasma voltage when using a new nozzle for the pure argon plasma and will enhance the enthaply,temperature and velocity of the plasma jet,simultaneously.In contrast with the pure argon plasma gas,in an Ar-N_2 mixtures gas plasma,the enthalpy,temperature and velocity of the plasma jet do not change much with the arc current and voltage when regulating the nitrogen proportion for the same condition of the equal power input to the gas.For Ar-H_2 plasma ,the increase of the H_2 content in the mixture can remarkably enhance the velocity and heat transfer of the plasma jet.