Numerical simulation and experimental investigation of transient anode surface temperature in vacuum arc

Abstract

In this paper, the spatial-temporal evolution of the anode temperature in the vacuum arc during the formation of an anode spot is investigated by numerical simulation and experiments. A transient self-consistent model is established to calculate the arc parameters and the anode temperature. The simulations predict that the maximum anode temperature always occurs after the current peak. Ion density and atom density at the anode side increase significantly during the formation of the anode spot. In the anode spot mode, more evaporated anode material comes into the arc column, leading to higher plasma temperature around the spot. The anode vapor can reduce the energy flux from the plasma to the anode center, providing more uniform anode temperature distribution and correspondingly smoother plasma parameter distributions in the vicinity of the anode center. In addition, a higher Cr fraction in the electrodes can result in a higher anode temperature. Near-infrared spectroscopy and high-speed camera thermography are used to study the anode temperature experimentally in order to verify the simulation results. A reasonable agreement was found.

Numerical investigation on transient arc characteristics and anode surface temperature considering the electrode movement

“…Figure 1 shows the physical model used in the simulation. As described in the previous work [18], the calculation areas I and II represent the vacuum arc area and the anode area respectively. The electrodes are made of CuCr25 with a diameter of 10 mm.…”

“…The electrodes are made of CuCr25 with a diameter of 10 mm. In calculation area I, various species including electrons, Cu atoms, Cr atoms, Cu ions (Cu 1+ , Cu 2+ , and Cu 3+ ), and Cr ions (Cr 1+ , Cr 2+ , and Cr 3+ ) are considered by solving corresponding fluid equations which take into account ionization and recombination processes [18]. In calculation area II, the anode temperature is calculated ignoring the anode surface deformation.…”

“…To study the transient characteristics of the vacuum arc and the anode, Shmelev et al [17] built a self-consistent model considering the radiation flux from the arc to the anode. In our previous work, a 2D transient model with coupling between the vacuum arc and the anode was established [18]. The simulation results were compared with experimental results.…”

“…In this paper, 2D transient model is built by coupling vacuum arc with anode considering opening process of electrodes and arc expansion process. Based on the previous model [18], dynamic mesh approach is added. The opening velocity and the arc expansion velocity are estimated using experimental data.…”

Anode Input Heat Flux Density in High-Current Vacuum Arcs as Anode Spot Formation

“…Although the vacuum arc diagnosis technology has been developed rapidly [21], [22], [23], [24], [25], [26], it is still challenging to experimentally measure the anode input heat flux density. In this work, a numerical method is used to obtain the heat flux density.…”