Comparison of Physical and Aerodynamic Ramps as Fuel Injectors in Supersonic Flow

Fuller, Raymond P.; Wu, Pei-Kuan; Nejad, A. S.; Schetz, Joseph A.

doi:10.2514/2.5278

Cited by 121 publications

(39 citation statements)

References 26 publications

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“…The aerothermodynamic probing method and data reduction algorithm employed during this research were similar to those used by Fuller et al (1998). They reported estimated uncertainties (within a 95% confidence interval) of the reduced data values as ∆M = ±1.7%, ∆P t = ±2.8%, ∆P = ±2.8%, ∆ρ = ±3.0%, ∆u = ±1.3%, and ∆T = ±0.8%.…”

Section: Appendix Bmentioning

confidence: 76%

“…They reported estimated uncertainties (within a 95% confidence interval) of the reduced data values as ∆M = ±1.7%, ∆P t = ±2.8%, ∆P = ±2.8%, ∆ρ = ±3.0%, ∆u = ±1.3%, and ∆T = ±0.8%. Fuller et al (1998) accounted for the mixture fractions of a binary gas in their data reduction, whereas this research assumed the flow the probes were exposed to consisted mostly of air alone. The uncertainties for the reduced quantities for this research may actually be lower, but the values used by Fuller et al (1998) provide an established, and possibly conservative, estimation of error.…”

Section: Appendix Bmentioning

confidence: 99%

“…Fuller et al (1998) accounted for the mixture fractions of a binary gas in their data reduction, whereas this research assumed the flow the probes were exposed to consisted mostly of air alone. The uncertainties for the reduced quantities for this research may actually be lower, but the values used by Fuller et al (1998) provide an established, and possibly conservative, estimation of error. The uncertainties of the computed enthalpy values are estimated to be ∆h = ±1.0%, and ∆(h/h t ) = ±2.5%.…”

Section: Appendix Bmentioning

confidence: 99%

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Performance Measurements of Direct Air Injection in a Cavity-Based Flameholder for a Supersonic Combustor

Edens¹

2006

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

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For several years the Air Force Research Lab Propulsion Directorate has been studying the difficulties in fueling supersonic combustion ramjet engines with hydrocarbon based fuels. Recent investigations have focused on the use of direct air injection into a directlyfueled cavity-based flameholder. Direct air injection has been shown qualitatively to be a valuable tool for improving cavity combustion. Little quantitative data is available that characterizes the performance of cavity-based flameholders. The objective of this research was to quantitatively determine the specific advantages and disadvantages of the direct air injection scheme. This was accomplished via intrusive probing into a supersonic free stream flow at an axial location behind the cavity flameholder. Pitot and static pressure, total temperature, and gas sampling measurements were taken and the corresponding values were processed to yield relevant engineering quantities. Data were taken over a range of fuel and air injection rates. Direct air injection resulted in increased combustion throughout the area of interest behind the cavity. Air injection increased the static temperature and pressure throughout the area of interest. Enthalpy spread into the free stream was also increased through the use of air injection. Total pressure losses increased as a result of the direct air injection scheme. The ratio of enthalpy increase to increase in total pressure losses increased with higher fuel flow rates, indicating that the direct air injection technique shows more promise for higher fuel loadings.iv

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Section: Appendix Bmentioning

confidence: 76%

Section: Appendix Bmentioning

confidence: 99%

Section: Appendix Bmentioning

confidence: 99%

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Performance Measurements of Direct Air Injection in a Cavity-Based Flameholder for a Supersonic Combustor

Edens¹

2006

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

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“…Various fuelinjection techniques, from different arrangements and shapes of flush-wall injectors to in-stream injection concepts (e.g., ramps, struts, etc. ), have been explored in an attempt to enhance the fuel-air mixing rate [1][2][3][4][5][6][7][8][9][10]. In general, the larger the disruption a fuel injector generates in the supersonic flow, the more effective the mixing of fuel and air.…”

Section: Nomenclaturementioning

confidence: 99%

“…A two-axis computer-controlled traversing mechanism allowed the probes to be positioned in the spatial region bounded by 8 < z=d < 8 and 0 < y=d < 9. These data were used in conjunction with the Raman-scattering data and a computerized solution algorithm developed by Fuller et al [5] to determine the time-averaged aerothermodynamic properties of the flowfield. Fuller et al also conducted an uncertainty analysis for the probe-based measurements; the results of this analysis are reproduced here: the uncertainties in stagnation pressure, Mach number, density, static pressure, static temperature, and velocity were determined to be 2.8, 1.7, 3.0, 2.8, 0.8, and 1.3% of the local values, respectively.…”

Section: In-stream Probingmentioning

confidence: 99%

Experimental Studies of Pylon-Aided Fuel Injection into a Supersonic Crossflow

Gruber¹,

Carter²,

Montes³

et al. 2008

Journal of Propulsion and Power

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information AFRL-RZ-WP-TP-2008-2170 SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING AGENCY ACRONYM(S)Air Force SPONSORING/MONITORING AGENCY REPORT NUMBER(S) AFRL-RZ-WP-TP-2008-2170 DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution unlimited. SUPPLEMENTARY NOTESPAO case number AFRL/WS07-0430, 28 February 2007. This is a work of the U.S. Government and is not subject to copyright protection in the United States. Document contains color. ABSTRACTAn investigation of the nonreacting flow associated with pylon-aided gaseous fuel injection into a Mach 2 crossflow is described. In this study, a small pylon was positioned just upstream of a circular flush-wall fuel injector. Three pylon geometries were studied, along with a no-pylon reference case. In all cases, a typical cavity-based flameholder was positioned downstream of the fuel injector. The injectant plume characteristics were interrogated using a variety of laser-based and probe-based measurement techniques. Planar laser-induced fluorescence of nitric oxide was used to study the instantaneous plume structure. Spontaneous vibrational Raman scattering provided time-averaged plume characteristics and mixing information. Probe-based instrumentation was used in conjunction with the mixing data to estimate the total pressure losses associated with each configuration. Each pylon had a unique influence on the fuel-injection plume. In all cases, the presence of the pylon resulted in improved fuel penetration into the supersonic crossflow without significantly changing the total pressure-loss characteristics. Mixing efficiencies of the pylonaided injection cases were not substantially different from the reference case. An investigation of the nonreacting flow associated with pylon-aided gaseous fuel injection into a Mach 2 crossflow is described. In this study, a small pylon was positioned just upstream of a circular flush-wall fuel injector. Three pylon geometries were studied, along with a no-pylon reference case. In all cases, a typical cavity-based flameholder was positioned downstream of the fuel injector. The injectant plume characteristics were interrogated using a variety of laser-based and probe-based measurement techniques. Planar laser-induced fluorescence of nitric oxide was used to study the instantaneous plume structure. Spontaneous vibrational Raman scattering provided time-averaged plume characteristics and mixing information. Probe-based instrumentation was u...

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A systematic literature review based on different fuel injection strategies used in scramjet combustors

Gugulothu

2019

Heat Trans. Asian Res.

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A supersonic combustion ramjet engine is an airbreathing propulsive system aimed at futuristic hypersonic vehicles. The profound advantages observed in the area of defence applications has attracted researchers' attention towards improving the fluid flow dynamics of scramjet engines. The present effort summarizes the fundamental problems and latest advances in fuel injection techniques. Improvements and application of modern fuel injection technologies have a profound impact on the scramjet engine, increasing capacity in terms of flight speed, efficiency in fuel mixing, and combustion. The fuel injection system has a direct impact on the engine's combustion processes, determining the scramjet engine's thrust power and its flight speed. A systematic database including brief descriptions of mixing enhancement mechanisms was analyzed numerically and experimentally, identifying the needed and existing fuel injection strategies. The numerical and computational analysis directly related to the experimental investigations is also included. K E Y W O R D S cavity, propulsion system, scramjet, transverse injection, vortex generator T A B L E 4 Active communities and their focus of research StudiesResearch focus

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Comparison of Physical and Aerodynamic Ramps as Fuel Injectors in Supersonic Flow

Cited by 121 publications

References 26 publications

Performance Measurements of Direct Air Injection in a Cavity-Based Flameholder for a Supersonic Combustor

Performance Measurements of Direct Air Injection in a Cavity-Based Flameholder for a Supersonic Combustor

Experimental Studies of Pylon-Aided Fuel Injection into a Supersonic Crossflow

A systematic literature review based on different fuel injection strategies used in scramjet combustors

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