Experimental Study on the Restrike Mode of a DC Arc Anode Attachment

The restrike mode is an important arc anode attachment mode under the cross flow in DC arc device, which often causes a large amplitude of arc voltage fluctuations and therefore has an important impact on the performance of arc thermal plasma device. A transferred arc device with planar anode parallel to gas flow direction is used to experimentally study the restrike mode characteristics under different operating conditions. It is found that for the case of a fixed gas flow, the arc restrike frequency increases while the amplitude of arc voltage jump decreases with the increase of arc current. For the case of a fixed arc current, both arc restrike frequency and amplitude of arc voltage jump increase with the increase of gas flow rates. Further analysis shows that the restrike process in one period can be divided into two phases. The first phase corresponds to the generation and development of upstream new arc roots and the disappearance of downstream old root, and its time scale is less than the order of 1 ms. The second phase corresponds to the newly formed, single arc root moving downstream under the combined action of gasdynamic drag force and Lorentz force until new arc root appears upstream. The time-resolved temperature field measurement based on the relative intensity of emission spectrum method shows that the temperature at the junction of the arc column and the anode arc root is relatively low, while it still able to maintain the current conduction, which indicates the significant deviation from thermodynamic equilibrium state.