Effects of Gas Components on the Jet Characteristics of a DC Plasma Torch by Using Orthogonal Test Method

For revealing the effects of gas components on the plasma jet characteristics, the corresponding jet characteristics of a home-made thermal plasma torch working with various gas components were experimentally studied by using the orthogonal test method. The experimental results showed that: 1) When nitrogen (N $_{2})$ is defined as the main working gas, the arc voltage, working power, thermal efficiency, and mean specific enthalpy all decrease with increasing argon (Ar). With the increase of helium (He), the mean specific enthalpy first decreases and then increases, while other three jet characteristics decrease. With the increase of hydrogen (H $_{2})$ , the arc voltage and working power increase, while the thermal efficiency and mean specific enthalpy decrease. 2) When Ar is defined as the main working gas, the mentioned four jet characteristics all increase with N $_{2}$ . With the increase of He, the thermal efficiency decreases, while other three jet characteristics increase. With the increase of H $_{2}$ , the arc voltage and working power increases, while the mean specific enthalpy varies little and the thermal efficiency decreases. 3) Besides, the gas volume percentage of the gas component is the uppermost influence factor of the jet characteristics.