Due to their favorable characteristics, e.g. high temperature, low operating cost and environmental requirements, direct current thermal plasma jets have been widely used. Correspondingly, in order to meet the different requirements of the diverse applications, different thermal plasma torches have been invented and their characteristics have been widely studied. The characteristics of a thermal plasma torch could be decided by its construction and working parameters. Though the influences of some factors on the characteristics of different thermal plasma torches have been experimentally and theoretically studied, there is little study on the influences of different gas flow rates on the characteristics of plasma torch working with two gas injection channels. Therefore, an optimized thermal plasma torch working with two gas injection channels has been proposed and its characteristics have been experimentally studied and discussed in this paper. The design considerations of the proposed plasma torch are discussed firstly. Then the experimental methods and results are introduced and discussed. The experimental results showed that the first gas flow rate nearing the cathode has little influences on the characteristics of the proposed thermal plasma torch while the second gas flow rate nearing the anode influences its characteristics obviously.

由于它们的有利特性，例如高温，低运行成本和环境要求，直流热等离子体射流已被广泛使用。相应地，为了满足不同应用的不同要求，已经发明了不同的热等离子体炬，并对其特性进行了广泛的研究。热等离子炬的特性可以由其构造和工作参数决定。尽管已经通过实验和理论研究了一些因素对不同热等离子体炬的特性的影响，但是很少研究关于不同气体流速对在两个气体注入通道下工作的等离子炬特性的影响。所以，提出了一种优化的带有两个注气通道的等离子炬，并对其特性进行了实验研究和讨论。首先讨论了所提出的等离子炬的设计考虑因素。然后介绍并讨论了实验方法和结果。实验结果表明，靠近阴极的第一气体流速对所提出的热等离子体炬的特性影响很小，而靠近阳极的第二气体流速对它的特性有明显的影响。