Fluorescence imaging of OH and NO in a model supersonic combustor

Allen, Mark G.; Parker, Terry; Reinecke, W. G.; Legner, Hartmut H.; Foutter, R. R.; Rawlins, W. T.; Davis, Steven J.

doi:10.2514/3.11358

Cited by 42 publications

(17 citation statements)

References 14 publications

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“…Previous work has primarily focused on developing diagnostic capabilities for these flows (Allen et al 1993;McMillin, Seitzman & Hanson 1994) and on investigating the ignition and stability characteristics of hydrogen transverse jets (Yoshida & Tsuji 1977;Lee et al 1992;Rothstein & Wantuck 1992;Heltsley et al 2007). More recently, work has also been directed at investigating the reacting characteristics of more complex fuel injection approaches that can be found in scramjet applications (Donbar et al 2000;Rasmussen et al 2007;Ryan et al 2009).…”

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confidence: 99%

Ignition, flame structure and near-wall burning in transverse hydrogen jets in supersonic crossflow

Gamba

Mungal

2015

J. Fluid Mech.

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We have investigated the properties of transverse sonic hydrogen jets in hightemperature supersonic crossflow at jet-to-crossflow momentum flux ratios J between 0.3 and 5.0. The crossflow was held fixed at a Mach number of 2.4, 1400 K and 40 kPa. Schlieren and OH * chemiluminescence imaging were used to investigate the global flame structure, penetration and ignition points; OH planar laser-induced fluorescence imaging over several planes was used to investigate the instantaneous reaction zone. It is found that J indirectly controls many of the combustion processes. Two regimes for low (<1) and high (>3) J are identified. At low J, the flame is lifted and stabilizes in the wake close to the wall possibly by autoignition after some partial premixing occurs; most of the heat release occurs at the wall in regions where OH occurs over broad regions. At high J, the flame is anchored at the upstream recirculation region and remains attached to the wall within the boundary layer where OH remains distributed over broad regions; a strong reacting shear layer exists where the flame is organized in thin layers. Stabilization occurs in the upstream recirculation region that forms as a consequence of the strong interaction between the bow shock, the jet and the boundary layer. In general, this interaction -which indirectly depends on J because it controls the jet penetration -dominates the fluid dynamic processes and thus stabilization. As a result, the flow field may be characterized by a flame structure characteristic of multiple interacting combustion regimes, from (non-premixed) flamelets to (partially premixed) distributed reaction zones, thus requiring a description based on a multi-regime combustion formulation.

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confidence: 99%

Ignition, flame structure and near-wall burning in transverse hydrogen jets in supersonic crossflow

Gamba

Mungal

2015

J. Fluid Mech.

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“…3. (18) As shown in Fig. 2, the strongest fluorescence of NO molecules in the UV region is observed around 237.0 nm.…”

Section: No Lif Detection and Calibrationmentioning

confidence: 94%

Laser-Induced Fluorescence (LIF) Probe for In-situ Nitric Oxide Concentration Measurement in a Non-thermal Pulsed Corona Discharge Plasma Reactor

Zhao

Garikipati

et al. 2005

Plasma Chem Plasma Process

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Laser-induced fluorescence (LIF) is an effective in-situ probe for NO concentrations below 300 ppm in a non-thermal plasma reactor. A new method has been developed to measure in-situ NO concentration in the reactor discharge region using a long-time-on the order of seconds-averaged fluorescence detection. This method, for quantifying NO concentration in a nonthermal plasma reactor, is simpler than a short-time-on the order of nanoseconds-fluorescence detection. For accurate measurement based on the new method, the LIF intensity must be close to the corona-induced fluorescence (CIF) intensity; the CIF intensity serves as a guide in selecting the LIF intensity. We find that a kinetic model proposed earlier works for two-tube reactors and represents the NO concentration in the middle of the reactor, which verifies the assumption of gas plug flow.

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“…= velocity x = distance°= speci c heat ratio°c = average speci c heat ratio, 1 2 .°0 C°3/ c = compression ef ciency through a hypersonic vehicle diffuser µ = characteristic temperature for the ignition delay time º i = gas composition ½ = density ¿ c = chemical time ¿ i = ignition delay time Subscripts j , jet = jet properties at the injection exit 0 = atmosphere conditions 1 = driven section conditions Introduction T HE success of future hypersonic airbreathing propulsion systems will be largely dependent on ef cient injection, mixing, and combustion processes inside the supersonic/hypersonic combustion chamber. The combustor entry conditions (Mach number, static temperature, and pressure) of this type of engine depend on the ight conditions of the vehicle.…”

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confidence: 99%

Characterization of Expansion Tube Flows for Hypervelocity Combustion Studies

Ben‐Yakar

Hanson

2002

Journal of Propulsion and Power

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An expansion tube with an 89 mm inner diameter and a 12 m length was characterized for basic studies of the near-eld mixing and ame-holding characteristics of gaseous fuels injected in high-stagnation-enthalpy supersonic ows. The expansion tube provides a wide range of freestream conditions with little perturbation of test gas chemical composition. The latter is critical for supersonic-combustion studies in the high-stagnationenthalpy ows associated with hypersonic airbreathing propulsion systems. Efforts focused on achieving three operating points, simulating ight Mach 8, 10, and 12 stagnation-enthalpyconditions at the entrance of a supersonic combustor. The ability of the expansion tube to provide a steady-ow test time of adequate duration and a core ow of suf cient size for 2-mm jet-in-cross ow studies was veri ed. A core-ow size of 25 mm could be achieved in 6.2 MJ/kg stagnation-enthalpy ows with 400 ¹s of steady test time ( ight Mach 12 simulation). The primary effects of the boundary layer on the expansion tube ow were to extend the useful test time (in contrast with conventional shock-tube performance) and to decrease the core-ow size. NomenclatureDa = Damköhler number J = jet to freestream momentum ux ratio, (°pM 2 / j =.°pM 2 / 1 L = characteristic length L 1 = characteristic distance from edge of the injection plate L 2 = characteristic recirculation region length M = Mach number M s = shock Mach number M w = molecular weight p = static pressure q = dynamic pressure Re = Reynolds number T = static temperature t = time U = velocity x = distance°= speci c heat ratio°c = average speci c heat ratio, 1 2 .°0 C°3/ c = compression ef ciency through a hypersonic vehicle diffuser µ = characteristic temperature for the ignition delay time º i = gas composition ½ = density ¿ c = chemical time ¿ i = ignition delay time Subscripts j , jet = jet properties at the injection exit 0 = atmosphere conditions 1 = driven section conditions

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Fluorescence imaging of OH and NO in a model supersonic combustor

Cited by 42 publications

References 14 publications

Ignition, flame structure and near-wall burning in transverse hydrogen jets in supersonic crossflow

Ignition, flame structure and near-wall burning in transverse hydrogen jets in supersonic crossflow

Laser-Induced Fluorescence (LIF) Probe for In-situ Nitric Oxide Concentration Measurement in a Non-thermal Pulsed Corona Discharge Plasma Reactor

Characterization of Expansion Tube Flows for Hypervelocity Combustion Studies

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