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| Arc-Heater |
The 1.6 MW Arc-Heated Wind Tunnel is used to produce supersonic streams of extremely hot gas. The high enthalpy, long duration capability of this facility compliments the capabilities of the other facilities at the ARC. The gas flowing through the arc heater is heated by a powerful electric arc to produce a gas stream with bulk temperatures ranging from 3000 to 5000 K. The facility is based on a Thermal Dynamics F-5000 arc heater, donated from the USAF Arnold Engineering Development Center, which is powered by a Halmar 1.6 MW DC power supply. In addition, the facility also consists of a nitrogen injection system, a water cooling system, a vacuum system, a probe traverse system and a facility monitoring and protection system.
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The wind tunnel’s bulk total enthalpy output ranges from 4000 to 5800 kJ/kg, which is controlled by adjustments in the power supply’s output of current and the rate that gas is injected into the arc heater. The arc heater can be configured to produce a very peaked enthalpy distribution across the nozzle exit, which can give local total enthalpies roughly twice the bulk average level. Facility operations have demonstrated mass flow rates from 0.07–0.18 kg/s. The corresponding maximum run duration is 90–200 s. The maximum operating pressure for the arc heater is 20 atmospheres. A compressed air driven ejector pump provides vacuum conditions in the test section vessel during test runs. The ejector pump has produced test section pressures as low as 4.5 kPa (0.65 psia) without the arc heater running. A mechanical vacuum pump is available to provide a high initial vacuum in the facility’s 4.25 cubic meter vacuum tank. The vacuum capability of the facility enables the use of high expansion ratio nozzles with the arc heater. A programmable, 3-axis traverse system allows probe surveys to be performed within a space of 20 cm wide, 23 cm long and 30 cm deep (8 x 9 x 12 in.). This system can be used to mount models or test articles as well. |
Click on the links to view the two ARC-Heater videos: ARCHeat.mpg and ARCRUN.avi |
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