Calibration of a newly developed direct-connect high-enthalpy supersonic combustion research facility

Reynolds averaged Navier-Stokes calculations have been performed for a U.S. Air Force Research Laboratory/ Aerospace Propulsion Of ce scramjet combustor designed for Mach 4.0-6.5 ight. The combustor owpath is unique in that it is entirely free of ow obstructions with fuel injection from wall-mounted injection ports and ameholding established by means of a recessed cavity. Calculations were performed at the minimum (Mach 4.0) and maximum(Mach 6.5) ight design conditions. The combustor operated in dual mode at the Mach 4.0 condition. The precombustion shock train formed a region of low-momentum/separated ow adjacent to the combustor side wall. This proved to be a primary source of ameholding, with the recessed cavity adding additional ameholding support. The ow was not thermally choked at the Mach 6.5 condition, resulting in very little upstream interaction. The mixing process at the Mach 4.0 ight condition was considerably more ef cient than that seen at the Mach 6.5 condition, due primarily to the shock-induced ow distortion and larger residence time. Even with the reduced mixing levels predicted at the Mach 6.5 condition, the combustion ef ciency was comparable to that achieved at the Mach 4.0 condition. The solutions obtained for dual-mode operation were particularly sensitive to choice of turbulence model and values speci ed for the turbulent Prandtl and Schmidt numbers. Overall, the solution sensitivity to grid resolution was small relative to the solution sensitivity to modeling uncertainties.

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“…A detailed discussion of the facility may be found in Ref. 2. The variablegeometry heat-sink combustor described in Ref.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Dual-Mode Hydrocarbon Scramjet Operation at Mach 4-6.5

Baurle

Eklund

2002

Journal of Propulsion and Power

133

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“…[16][17][18] The Air Force test facility, in contrast, provides a long duration high enthalpy flow which is well suited for testing new instrumentation and for developing meaningful statistical information regarding the sensor's performance. 19…”

Section: Introductionmentioning

confidence: 99%

Diode Laser Sensor for Gasdynamic Measurements in a Model Scramjet Combustor

2000

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A sensor for simultaneous and continuous measurements of water vapor density, temperature and velocity has been developed based on absorption techniques using room temperature diode lasers (InGaAsP) operating at 1.31 µm. Laboratory calibrations of density and temperature were acquired in a variable temperature absorption cell and on a H 2-air flat flame burner from 500 to 2200 K. Laboratory determinations showed absolute accuracies of 5% in temperature and 10% in molecular density for a 0.3 Hz bandwidth. An optical system was developed for integrating the sensor to a model SCRAMJET combustor at the Air Force Research Laboratory Wright-Patterson Air Force Base. Preliminary measurements in the Mach 2.1 flow field at expanded temperatures of 540, 650, and 740 K across an 18 cm pathlength resulted in temperature measurements that agreed with theoretical predictions to within 7 to 11%. Density measurements agreed with predictions to within 17 to 56%. Velocity measurement precision was compromised by beam steering effects, although results in reasonable agreement with predictions were observed at the lowest enthalpy condition.

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