Development and Calibration of an Axisymmetric Direct-Connect Supersonic-Combustion Flowpath

Smith, Stephen D.; Gruber, Mark; Steiner, R.; Collatz, MacKenzie J.; Afb, Wright-Patterson; Mathur, Tarun; Ohio, Dayton

doi:10.2514/6.2009-5035

Cited by 13 publications

(6 citation statements)

References 3 publications

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“…The isolator has a 0.25° divergence angle and was used for all combustion experiments described in this analysis. 5 Two combustor configurations were analyzed; the first was a fully divergent combustor; the second configuration used a constant area section with step. Figure 1 shows a flowpath schematic of one of the configurations.…”

Section: Methodsmentioning

confidence: 99%

Dual-Mode Scramjet Combustor: Numerical Sensitivity and Evaluation of Experiments

Milligan

Liu

Tam

et al. 2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Experiments were performed at the Air Force Research Laboratory's Propulsion Directorate (AFRL/RZ) in Research Cell 22 (RC22). Twelve cases from the experiment were computationally analyzed and each case varied in either engine operating condition and/or combustor configuration. Initial computations were performed on all twelve cases to establish a baseline computational approach. Computations were performed on one of the cases to test sensitivity to turbulent Schmidt number, reaction rate, and grid resolution. Improvements to the baseline analysis using the results from the sensitivity analyses were extended to two additional cases. It was shown that adjustments in Schmidt number, reaction rate, or grid refinement improved the agreement with experimental data for two cases relative to the baseline results, but worsened agreement for the third case. It was left undetermined that grid refinement was a better approach to improving the baseline analysis as compared to calibrations in Schmidt number and/or reaction rate. Improvement to the grid using local refinement in regions with chemical reactions produced better results for one case and was computationally less expensive than globally refining the grid. Negligible differences were shown between results that were obtained using wall functions with Y+ value as high as 38 or results obtained using wall integration with Y+ values around one. Negligible differences were shown between periodic results that were obtained by averaging results using either a constant CFL or a constant time step. CFL-averaging a result using the constant CFL approach was 5.4 times less computationally expensive than using the constant time step approach. Computations showed that 2.53-lbm/sec. of air leaked into the exhauster housing at the exit of the combustor in RC22's test apparatus.

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Section: Methodsmentioning

confidence: 99%

Dual-Mode Scramjet Combustor: Numerical Sensitivity and Evaluation of Experiments

Milligan

Liu

Tam

et al. 2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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“…The purpose of the cavity injectors are to assist and stabilize cavity flames, but are not typically used as a primary fueling source. Information regarding the current RC22 setup that includes development and calibration of the isolator is found in [2]. Detail on the pitot probe measurements is contained in [3].…”

Section: Methodsmentioning

confidence: 99%

Dual-Mode Scramjet Combustor: Numerical Analysis of Two Flowpaths

Milligan

Eklund

Wolff

et al. 2011

Journal of Propulsion and Power

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“…10 The air flow supplied by the RZA research facility is on the order of 10 lb/s and the scramjet engines being tested are considered to have a geometric scale of 1X. Figure 1 shows a schematic of the RC22 flowpath examined, which consists of a facility nozzle, an optical calibrator, an isolator, a divergent combustor with a cavity flameholder, and a probe housing.…”

Section: Problem Descriptionmentioning

confidence: 99%

Radiative Heating in Hydrocarbon-fueled Scramjet Engines

Liu¹,

Afb²,

Brown³

2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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Radiation may play an important role in the wall heating and flow cooling of scramjet engines. There have, however, been very few studies in this area, partially due to the inherent difficulties involved. In the present study, an AFRL/RZA RC22 axisymmetric scramjet design was investigated at different fuel splits, Mach numbers, and geometric scales, in order to understand the effects of radiative heat transfer in hydrocarbon-fueled scramjet engines. The results of interest in this study are the radiative and convective heat transfer on the walls of nine components in the test section, including the facility nozzle, isolator, and combustor. For the baseline case with Mach 2.2 nozzle and φ p /φ s =0.32/0.58, it was found that the radiative wall heat flux was elevated in the combustor and the predicted radiative wall transfer rates were between 1-4% of the corresponding convective wall transfer rates for the five combustor components. For another two cases with the same nozzle Mach number and different fuel splits, the radiation contribution to the wall heat transfer was found to be similar to the baseline case. For the case with Mach 1.8 nozzle, the flow temperature and speed are reduced, and so are the predicted convective and radiative wall heat fluxes. The radiation contribution for this case appeared to be similar to the baseline case. With an increase of combustor scale from 1X to 10X, the radiative wall heat flux is increased while the convective wall heat flux is decreased. This opposite change trend results in a significant increase of the radiation contribution to the wall heat transfer in comparison to the convective heat transfer. For the two cases with 10X combustor scale, the radiative wall transfer rate was found to exceed 10% of the convective wall transfer rate for some combustor components. This implies that radiative heat transfer can no longer be neglected in the scramjet thermal analysis and the radiative effects on the flowfield may also have to be considered in scramjet performance analysis.

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Development and Calibration of an Axisymmetric Direct-Connect Supersonic-Combustion Flowpath

Cited by 13 publications

References 3 publications

Dual-Mode Scramjet Combustor: Numerical Sensitivity and Evaluation of Experiments

Dual-Mode Scramjet Combustor: Numerical Sensitivity and Evaluation of Experiments

Dual-Mode Scramjet Combustor: Numerical Analysis of Two Flowpaths

Radiative Heating in Hydrocarbon-fueled Scramjet Engines

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