Flow Distortion: Computational Investigation of a Shocked Cavity Flameholder

Milligan, Ryan T.; Boles, John A.; Hagenmaier, Mark A.; Donbar, Jeffrey M.; Carter, Campbell D.; Hsu, Kuang–Yu

doi:10.2514/6.2013-2838

Cited by 14 publications

(7 citation statements)

References 5 publications

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“…Pressure data in the immediate vicinity of the cavity indicate even smaller changes, suggesting that the particular region of interest of the flowfield is not appreciably affected by the seeding method used. This result is confirmed by recent CFD analysis 27,28 .…”

Section: Resultssupporting

confidence: 92%

Velocimetry Measurements of a Scramjet Cavity Flameholder with Inlet Distortion

Kirik

Goyne

Peltier

et al. 2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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Particle image velocimetry (PIV) measurements were made in the center plane of a scramjet cavity flameholder to analyze the effects of simulated inlet flow distortion in the direct-connect test environment. Mach 3 non-reacting tests examined the effects of a fullspan wedge configured such that an oblique shock impinged upon locations in and upstream of the cavity flameholder, including cases with wall-normal air injection upstream of the cavity to simulate fuel injection. Addition of flow distortion altered the size and shape of the primary recirculation region within the cavity by deflecting the bounding shear layer: the recirculation region was compressed by shock impingement upstream of the cavity, while shock impingement on the cavity itself expanded it. Air injection upstream of the cavity thickened the shear layer and produced a stronger effect on velocity direction than magnitude, preventing the formation of a large-scale recirculation region in two of the three shock locations studied. Flow distortion and air injection both increased flow unsteadiness, with the greatest increases in root-mean-square velocity occurring in the shear layer and above the cavity closeout ramp. At the most-upstream shock impingement location examined, flow patterns indicated fuel injected through the ramp at the center plane may not be recirculated within the cavity, providing a potential mechanism for a previouslyobserved lack of flameholding in this configuration. Additionally, results suggest the formation of spanwise secondary flow patterns that may account for flow nonuniformities observed in prior studies. This work presents the first PIV characterization of a scramjet cavity flameholder under distorted-flow conditions and with simulated upstream fuel injection.

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Section: Resultssupporting

confidence: 92%

Velocimetry Measurements of a Scramjet Cavity Flameholder with Inlet Distortion

Kirik

Goyne

Peltier

et al. 2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

Self Cite

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“…In a prior investigation with this same flowpath and distortion configuration, combustion could not be initiated with fueling from the ramp face [23]. CFD analysis of the same configuration suggested that short residence time and low static pressure near the sparkplug ignition sources may have been primarily responsible for the observed lack of ignition [22]. Flow with shock impingement on the jet injector (case 3a) also shows shear layer deflection similar to that in case 2a but to a lesser extent.…”

Section: A Jet Q Equal To Zeromentioning

confidence: 52%

“…Spanwise flow patterns were found in earlier work in the same facility, where measurements of the OH radical using planar laser-induced fluorescence indicated a spanwise-asymmetric combustion product distribution, despite a spanwise-symmetric fuel-injection configuration [31]. Spanwise flow patterns were also suggested by numerical analysis of this flowpath under distorted-flow conditions [22]. Attempts in previous work to sustain combustion at the shock-oncavity condition were successful both with and without fueling through the jet injector in addition to the cavity ramp [23], so it is clear that this mode of cavity operation does not preclude stable combustion.…”

Section: B Jetmentioning

confidence: 71%

“…Attempts in previous work to sustain combustion at the shock-oncavity condition were successful both with and without fueling through the jet injector in addition to the cavity ramp [23], so it is clear that this mode of cavity operation does not preclude stable combustion. CFD analysis indicated that this configuration results in relatively high pressures in the cavity, thus enhancing flameholding potential [22].…”

Section: B Jetmentioning

confidence: 98%

“…This configuration was previously characterized experimentally using planar laser-induced fluorescence of the OH and NO species [22,23]. Apart from the inclusion of a distortion generator and the use of a Mach 3 nozzle in place of a Mach 2 equivalent, this flowpath is the same as that studied by Tuttle et al, who found that the shear layer did not reattach to the cavity floor [17], confirming the expected behavior based on the cavity length-to-depth ratio of 4.0.…”

Section: A Experimental Facilitymentioning

confidence: 99%

See 2 more Smart Citations

Velocimetry Measurements of a Scramjet Cavity Flameholder with Inlet Distortion

Kirik¹,

Goyne²,

Peltier³

et al. 2014

Journal of Propulsion and Power

Self Cite

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Particle image velocimetry measurements were made along the center plane of a scramjet cavity flameholder to analyze simulated inlet flow distortion in the direct-connect test environment. Mach 3 nonreacting tests examined an oblique shock impinging upon locations in-and upstream of the cavity, including cases with wall-normal air injection upstream of the cavity to simulate fuel injection. Addition of flow distortion altered the size and shape of the primary recirculation region within the cavity by deflecting the bounding shear layer: the recirculation region was compressed by shock impingement upstream of the cavity, and shock impingement on the cavity itself expanded it. Air injection upstream of the cavity thickened the shear layer and produced a stronger effect on velocity direction than magnitude, preventing the formation of a large-scale recirculation region in two of the three shock locations studied. Flow distortion and upstream air injection both increased flow unsteadiness, with the greatest increases occurring in the shear layer and above the cavity closeout ramp. Additionally, results suggest the formation of spanwise secondary flow patterns that may account for flow nonuniformities observed in prior studies. This work presents the first velocimetry characterization of a scramjet cavity flameholder under distorted-flow conditions.

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