Plasma simulations reveal important parameters affecting inductive discharges

Inductively coupled plasma (ICP) wind tunnels are a useful proxy for modeling the heating of the thermal protection systems of spacecraft reentry. The heat resistance performance of these materials can be tested by installing them into an ICP wind tunnel. To help inform the design of plasma-based aircraft protection systems, Yu et al. conducted simulations of plasmas in a medium-powered ICP wind tunnel to better understand the significance of various parameters on plasma discharge properties.

To the authors, the most noteworthy findings were the effects of the number of turns in the induction coil of the plasma discharge tube and the impacts of the gas working pressure. An increasing number of coil turns results in a decrease of electric field intensities, reducing the Lorentz forces in both the axial and the radial direction. This ultimately leads to an increase in the total power absorbed by the plasma.

On the other hand, increasing the inlet gas pressure causes energy transfers between hot and cold particles to occur more frequently, leading to a smaller maximum temperature for the plasma.

The group studied the effects of these and other working parameters numerically by solving the system’s coupled flow-field equations. They used a combination of methods to overcome the characteristic time differences of the various competing processes and obtain flow-field parameters that can be used as inputs for future simulations of aircraft protection materials.

“Through the plasma wind tunnel tests, we hope to find the most suitable thermal protection materials that are light in weight and have high heat resistance to high-temperature ablation,” said author Minghao Yu.

Source: “Effects of the working parameters on the flow-field numerical results for a medium-power ICP wind tunnel,” by Minghao Yu, Yiwen Li, Zhe Wang, Ge Chen, and Xiaolong Wei, Physics of Plasmas (2020). The article can be accessed at https://doi.org/10.1063/5.0004824 .