1MWアーク加熱風洞でのガス噴射による通信ブラックアウト低減化研究

抄録

Telecommunication between an atmospheric entry vehicle and the grand station can be interrupted by a high-density plasma caused by aerodynamic heating called a communication blackout. Plasma attenuates the electromagnetic waves for telecommunication, making it impossible to obtain the positioning information and the observation data. Reduction of the density of the electron density around the vehicle is important to mitigate the communication blackout. In this study, we focused on a thin air film layer formed by gas injection as a mitigation method of communication blackout during atmospheric reentry. The arc-heated wind tunnel experiment was numerically reproduced based on computational fluid dynamics (CFD). Plasma density was low in the air film layer. The cold gas formed the propagation path of the communication wave. We also performed a gas injection experiment to observe the jet shape by Schlieren imaging. It revealed the density distribution around the injection outlet. It was found that the shock wave formed in front of the jet. Comparing the Schlieren photography with the CFD results shows qualitative agreement. Therefore, numerical analysis and wind tunnel tests both show that the plasma can be moved away from the surface by injecting cold gas in a high enthalpy airflow.