1200 KW Induction Plasmatron
The Plasmatron is a high enthalpy facility in which a jet of plasma is generated in a test chamber kept at sub-atmospheric pressure (between 5 and 350 mbar). The plasma is generated by heating a gas (argon, N2 ,CO2 ,air or any other gas mixture) to temperatures up to about 10000 K, using electrical current loops induced inside a plasma discharge. Electrodeless inductively-coupled plasma generators of this type offer much better plasma purity compared to classical arcjets, as there is no pollution from any vaporized electrode material.
The facility, which is the most powerful induction-coupled plasma wind tunnel in the world, uses a high frequency, high power, high voltage (400 kHz, 1.2 MW, 2 kV) solid state (MOS technology) generator, feeding the single-turn inductor of an 80mm or 160mm diameter plasma torch. The torch is mounted on a 1.4m diameter, 2.5m long, water-cooled test chamber, fitted with nine 500mm diameter portholes that allow unrestricted optical access to the horizontally oriented plasma jet. Hot gas from the test chamber exits trough a 700 kW heat exchanger to a group of three rotary-vane vacuum pumps and a Roots pump, which are capable of extracting 9000 m3/h, with a terminal vacuum capability of 0.005 mbar.
A 1050 kW cooling system using a closed loop deionized water circuit (2090 litres/min) and fan-driven air coolers provide cooling to all facility components. The facility is computer controlled using a 719 I/O lines PLC, and two PC’s for controlling and monitoring the Plasmatron operation. A dedicated 96-channel data acquisition system using a 12-bit A/D converter at 100 kHz is also available. The facility is used for space re-entry materials testing at heat fluxes up to 15 MW/m2, including catalycity determination, as well as for general studies of plasma flows. The Plasmatron facility is equiped with a sonic nozzle, two supersonic nozzles (Mach: 2,6 and 3,2) and a semi-eliptic nozzle for supersonic testing. Available instrumentation includes intrusive cooled pressure and heat flux probes, a one-meter emission spectrometer with CCD camera and a two-color pyrometer. In addition, a dedicated laser-spectroscopy laboratory is currently being developed for plasma diagnostics.
Advanced numerical modelling capability is also available to assist in designing experiments, to extract more information from test results, and for relating test conditions to flight.