Test Capabilities and Recent Experiences in the NASA Langley 8-Foot High Temperature Tunnel

Jeffrey S. Hodge* and Stephen F. Harvin*NASA Langley Research CenterHampton, VAABSTRACTThe NASA Langley 8-Foot High Temperature Tunnel is a combustion-heated hypersonic blowdown-to-atmosphere wind tunnel that provides flight enthalpy simulation for Mach numbers of 4, 5, and 7 through an altituderange from 50,000 to 120,000 feet. The open-jet test section is 8-ft. in diameter and 12-ft. long. The test section willaccommodate large air-breathing hypersonic propulsion systems as well as structural and thermal protection systemcomponents. Stable wind tunnel test conditions can be provided for 60 seconds. Additional test capabilities areprovided by a radiant heater system used to simulate ascent or entry heating profiles. The test medium is thecombustion products of air and methane that are burned in a pressurized combustion chamber. Oxygen is added tothe test medium for air-breathing propulsion tests so that the test gas contains 21 percent molar oxygen. The facilitywas modified extensively in the late 1980's to provide airbreathing propulsion testing capability. In this paper, abrief history and general description of the facility are presented along with a discussion of the types of supportedtesting. Recently completed tests are discussed to explain the capabilities this facility provides and to demonstratethe experience of the staff.8-Ft. HTTESPFMSGH2GN2HXEMHXFELN2LOXNASANASPPLCPSIRDASTCNTPSTSBNOMENCLATURENASA Langley 8-Foot High TemperatureTunnelelectronically scanned pressurethree measurement systemgaseous hydrogengaseous nitrogenHyper-X engine modelHyper-X flight engineliquid nitrogenliquid oxygenNational Aeronautics and SpaceAdministrationNational Aero-Space Planeprogammable logic controllerPressure Systems Incorporatedresearch data acquisition systemtranspiration-cooled nozzlethermal protection systemNASA Langley Research Center ThermalStructures Branch"Aerospace Engineer, Research Facilities Branch,Aerodynamics, Aerothermodynamics and AcousticsCompetency, NASA Langley Research Center, MS395, Hampton, VA 23681.Copyright © 2000 by the American Institute ofAeronautics and Astronautics. Inc. No copyright isasserted in the United States under Title 17, U.S. Code.The U.S. Government has a royalty-free license toexercise all rights under the copyright claimed hereintbr Governmental Purposes. All other rights arereserved by the copyright owner.INTRODUCTIONConstruction of the 8-Foot High TemperatureTunnel (8-Ft. HTT) was initiated in March 1959 andcompleted in early 1964. Facility shakedown andcheckout began in June 1964 and the first hot tunnel runwas achieved in August 1965. Many tunnel tlowsurveys and blockage studies were conducted duringthe first several years of operation. Research tests wereconducted for reentry configurations, hypersonicthermal structures, and fundamental hypersonicresearch benefiting activities such as the Scout program(1966), and the Hypersonic Research Engine StructuralAssembly Model I (1971). However, lull operation ofall systems (including model injection system, modelpitch system, and model radiant heating) over a widerange of conditions (600-2900 psi at 3000°F) was notdemonstrated until November 1973. The facility wasoriginally named the 8-Foot High TemperatureStructures Tunnel because it was used to test structuresand materials concepts designed to withstandhypersonic aerothermal environments. During the1970's, the facility supported the Shuttle program(Shuttle Reusable Surface Insulation Tiles 2, ShuttleInfrared Leeside Temperature Sensing) and thermalprotection system (TPS) development. Another effortsupported by the facility was the X-24C program, aMach 8 lifting body that would providc a testbed forscramjet engines and TPS materials. The 8-Ft. HTTwas used to perform gap heating tests, and otherstudies, in support of the X-24C program. During thelate 1970's and early 1980's the facility became moreinvolved in defense programs such as the StrategicDefense Initiative. The 8-Ft. HTT was used to testIAmerican Institute of Aeronautics and Astronautics