Study of a supersonic combustor employing an aerodynamic ramp pilot injector

Eklund, Dean; Gruber, Mark

doi:10.2514/6.1999-2249

Cited by 19 publications

(6 citation statements)

References 7 publications

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“…Previous dual-mode calculations 5 have shown a strong dependence of the solutionto the valuesspeci ed for the turbulentSchmidt and Prandtl numbers. Thus, existing isolator pressure measurements (at three conditions close to the simulated conditions) were used to assess the adequacy of the chosen values of 0.5 for Sc t and 0.89 for Pr t .…”

Section: Resultsmentioning

confidence: 97%

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

Baurle

Eklund

2002

Journal of Propulsion and Power

130

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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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Section: Resultsmentioning

confidence: 97%

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

Baurle

Eklund

2002

Journal of Propulsion and Power

130

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“…Currently, two most widely used ethylene combustion models to support the HyTech program are the 10-step quasi-global reaction mechanism developed by Singh and Jachimowski 14 and the 3-step global mechanism developed by researchers at AFRL. 13 These two models have been validated over a certain range of initial pressure, temperature, and equivalence ratio conditions based on the ign. While these two models are very simple to apply, studies at AFRL and other organizations have shown great discrepancies between experiment measurements and the results obtained using these two models.…”

Section: Comparisons Of Results Among the Reduced Mechanism And Twmentioning

confidence: 99%

“…Constant values for these numbers are usually assumed in applications, although their values have been found to vary spatially. 9,10 Calculations performed by various authors 11,12,13 have shown strong sensitivity of the solution to these numbers, especially to Sct. Therefore, extreme care should be taken when attempting to characterize scramjet engines with constant turbulent transport coefficients.…”

Section: Vulcan Cfd Codementioning

confidence: 99%

Simulations of Cavity-stabilized Flames in Supersonic Flows Using Reduced Chemical Kinetic Mechanisms

Liu

Tam

et al. 2006

42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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“…Choice of a unique value of these parameters for a simulation of a complex flow, especially in the case where no information is available about the turbulent Prandtl/Schmidt number variations can lead to incorrect predictions. Several computations [6][7][8][9] performed by different authors have at times shown an extreme sensitivity to values assumed for these parameters. For example, in the study carried out by Baurle and Eklund 7 for a scramjet combustor at Mach 4.0 flight condition, a variation of turbulent Schmidt number from 0.25 to 0.75 resulted in unstart of the intake due to intense heat release at lower turbulent Schmidt number and unsustained combustion due to low turbulent mass transfer at higher turbulent Schmidt number.…”

Section: Introductionmentioning

confidence: 99%

Behaviour of turbulent Prandtl/Schmidt number in compressible mixing layer

Javed

Rajan

Chakraborty

2014

Proceedings of the Institution of Mechanical Engineers, Part G:

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The behaviour of turbulent Prandtl/Schmidt number is explored through the model-free simulation results. It has been observed that compressibility affects the Reynolds scalar flux vectors. Reduced peak values are also observed for compressible convective Mach number mixing layer as compared with the incompressible convective Mach number counterpart, indicating a reduction in the mixing of enthalpy and species. Pr t and Sc t variations also indicate a reduction in mixing. It is observed that unlike the incompressible case, it is difficult to assign a constant value to these numbers due to their continuous variation in space. Modelling of Pr t and Sc t would be necessary to cater for this continuous spatial variation. However, the turbulent Lewis number is evaluated to be near unity for the compressible case, making it necessary to model only one of the Pr t and Sc t. .

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Study of a supersonic combustor employing an aerodynamic ramp pilot injector

Cited by 19 publications

References 7 publications

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

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

Simulations of Cavity-stabilized Flames in Supersonic Flows Using Reduced Chemical Kinetic Mechanisms

Behaviour of turbulent Prandtl/Schmidt number in compressible mixing layer

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