Performance of Aft-Ramp Cavities for Flame Stabilization in Supersonic Flows
01 May 2008-Journal of Propulsion and Power (American Institute of Aeronautics and Astronautics (AIAA))-Vol. 24, Iss: 3, pp 635-637
About: This article is published in Journal of Propulsion and Power.The article was published on 2008-05-01. It has received 14 citations till now. The article focuses on the topics: Supersonic speed & Pressure coefficient.
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TL;DR: In this paper, a strut-cavity-based scramjet combustor with kerosene and pilot hydrogen as fuels was experimentally investigated, and the dominant modes of pressure oscillations were strongly influenced by the cavity aspect ratio.
34 citations
TL;DR: In this paper, the effects of thermal throat on flame stabilization in a kerosene fueled supersonic combustor were numerically and experimentally studied under the inflow condition of stagnation temperature 1100 K, stagnation pressure 1.0 MPa and Mach number 2.0.
33 citations
TL;DR: In this paper, the authors compared the ignition ability of two cavities with different length based on the wall pressure distribution along the combustor and the thrust evolution, and the experimental results indicated that the longer cavity (L/D=7) is more suitable than the smaller cavity (l/D = 5) in spark ignition.
25 citations
TL;DR: In this article, a new solid rocket scramjet equipped with two combined cavity and strut device was studied by experimental and numerical approaches, and the experimental results showed that the combined cavity can play a role as ignition and flame holding in the solid rocket scrambling combustor.
23 citations
01 Dec 2017
TL;DR: In this article, the effective means of air fuel mixing and flame holding can be achieved by incorporating cavity in supersonic combustor, and the complex flow field of cavity flow is essential for the de...
Abstract: The effective means of air fuel mixing and flame holding can be achieved by incorporating cavity in supersonic combustor. Understanding the complex flow field of cavity flow is essential for the de...
18 citations
References
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TL;DR: In this paper, the authors investigate the effect of the aft ramp angle on the character of the shear layer that spans the cavity in a nonreacting supersonic ship.
Abstract: Experimentalandcomputationalinvestigationsofthee owe eldassociatedwithseveralcavity-basede ameholders in a nonreacting supersonic e ow are described. All cavity e ows were of the open type, that is, length-to-depth ratio L/D<10. Two values of L/D were studied with several offset ratios (OR) and aft ramp angles µ. Results indicate that the aft ramp angle plays an important role in determining the character of the shear layer that spans the cavity. For a rectangular cavity with OR=1 and µ=90 deg, a compression wave forms as the e ow separates from the cavity’ s upstream corner. A strong recompression occurs at the aft wall, and the e ow is visibly unsteady. The pressure on the cavity fore wall decreases steadily and the recompression process occurs more gradually with decreasing aftrampangle.Higherdrag coefe cientsandshorterresidencetimesarefoundin cavitieswithshallower ramp angles.
398 citations
24 Mar 1975
285 citations
01 Jan 2005
TL;DR: In this paper, the authors examined the stability of hydrocarbon-fueled flames in cavity flameholders in supersonic airflows and found that cavity ramp injection provided better performance near the lean blowout limit whereas injection from the cavity floor resulted in more stable flames near the rich limit.
Abstract: Experiments were performed to examine the stability of hydrocarbon-fueled flames in cavity flameholders in supersonic airflows. Methane and ethylene were burned in two different cavity configurations having aft walls ramped at 22.5° and 90°. Air stagnation temperatures were 590 K at Mach 2 and 640 K at Mach 3. Lean blowout limits showed dependence on the air mass flowrates, cavity geometry, fuel injection scheme, Mach number, and fuel type. Large differences were noted between cavity floor and cavity ramp injection schemes. Visual observations, planar laser-induced fluorescence of nitric oxide, and shadowgraph imaging were used to investigate these phenomena. Cavity ramp injection provided better performance near the lean blowout limit, whereas injection from the cavity floor resulted in more stable flames near the rich limit. Ethylene flames have a wider range of stable operations than methane in all conditions. Lean blowout limits were not significantly different between the Mach 2 and Mach 3 cases at the lean limit; however, variation in Mach number had a measurable effect near the rich limit. Fuel flowrates at ignition were much greater than the lean blowout limit, but showed similar dependence on air mass flowrate.
159 citations
TL;DR: In this paper, the authors evaluated the holding and mixing enhancement characteristics of supersonic reacting e ow over acoustically open cavities and found that cavity cone gurations improved combustion performance.
Abstract: An experimental study was performed to evaluate the e ame-holding and mixing enhancement characteristics of supersonic reacting e ow over acoustically open cavities. Several cone gurations of acoustically open cavities were placed inside a supersonic-combustion duct just downstream of the fuel injection ports. The resulting changes in e ame behavior and combustion characteristics were assessed using schlieren visualization of the uncone ned e ow and wall pressure measurements of the cone ned e ow along the duct. The results were then compared with the baselinecase, which used no cavity. Although thecavitiesimproved thecombustion performancefrom thebaseline, the amount of enhancement was dependent on the particular shape of the cavity as well as the e ow conditions. Certain cavity cone gurations that were strategically placed inside the combustion duct led to a faster increase in the axial pressure force. The data showed that the recovery temperature was higher and the total pressure proe le was more uniform at the exit plane, suggesting enhanced volumetric heat release and faster mixing associated with the cavity- ine uenced e owe eld.
139 citations
TL;DR: In this article, the stability of a recirculation region formed in a wall cavity with ignition provided by hydrogen injected in the base of the cavity and injection of kerosene upstream in the boundary layer formed along the wall leading to the cavity was determined.
Abstract: The goal of this study was to determine the stability of the ame in a recirculation region formed in a wall cavity with ignition provided by hydrogen injected in the base of the cavity and injection of kerosene upstream in the boundary layer formed along the wall leading to the cavity. The experimental conditions, i.e., Mach 1.8 and air stagnation temperatures to 1000 K, correspond to the beginning of the hypersonic ight regime also referred to as cold start conditions. The hydrogen and the preinjected kerosene ow rates were modulated during the tests and temperature probes placed in the cavity indicated their effect on the local equivalence ratio. Preinjection of kerosene reduced the local equivalence ratio at low air stagnation temperature by increasing the entrainment of fresh air into the recirculation region. At high temperatures the additional fuel brought by the presence of kerosene had a detrimental effect on the stability of the ame in the cavity.
87 citations