Characterization of a 50kW Inductively Coupled Plasma Torch for Testing of Ablative Thermal Protection Materials

摘要

With the development of new manned spaceflight capabilities including NASA's Orion capsule and the Space-X Dragon capsule, there is a renewed importance of understanding the dynamics of ablative thermal protection systems. To this end, a new inductively coupled plasma torch facility is being developed at UT-Austin. The torch operates on argon and/or air at plasma powers up to 25 kW for input power up to 50 kW. In the present configuration the flow exits from a low-speed subsonic nozzle and the hot plume is characterized using slug calorimetry and emission spectroscopy. Measurements using emission spectroscopy have indicated that the torch is capable of producing an air plasma with a temperature between 5,000 K and 8,000 K depending on the power and flow settings and an argon plasma with a temperature of approximately 12,000 K. The temperature falls off from the central peak value by approximately 1,000 K at a radius of 8 mm. The facility operation envelope was determined, and heat flux was measured for selected points within the envelope using both a slug calorimeter and a Gardon gauge heat flux sensor. The torch was found to induce a stagnation point heat flux of between 90 and 225 W/cm~2. A small asymmetry of unknown cause which increases with increasing mass flow rate was found in the radial variation of heat flux.