High-enthalpy portable RF plasmatron for nonequilibrium flow analysis

Ground test facilities such as plasma torches are critical to understanding hypersonic flow and high enthalpy fields as they simulate hypersonic velocities and reentry conditions. In particular, they are used to reproduce the aerothermodynamic heating experienced by the aircraft during the entire flight. The purpose of this project was to develop an apparatus for high-enthalpy low-pressure plasma generation using an induction-coupled discharge. The installation is designed to develop new methods for plasma diagnostics and testing of thermal insulating materials. The installation provide a continuous plasma flow with a mass flow rate of up to 0.1 grams per second with a specific enthalpy of up to 20 MJ/kg. The installation uses a standard high-frequency generator at frequency of 13.56 MHz and RF power 1.5 kW. The vacuum and cooling systems allow continuous operation of the installation for several hours. The inductor is made of a copper tube and is cooled with de-ionized water. The discharge chamber is equipped with 5 quartz windows along all 3 axes to provide control of the uniformity of the plasma flow, and the possibility of remote plasma diagnostics by spectroscopic methods. The results of temperature and flow field measurements are discussed.