Experimental investigation of angled injection in a compressible flow

Hartfield, Roy J.; Bayley, Douglas

doi:10.2514/3.24054

Cited by 11 publications

(4 citation statements)

References 9 publications

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“…angle, staging, etc.) (Bier, Kappler & Wilhelmi 1971;McDaniel & Graves 1988;Hartfield & Bayley 1995). Similarly to underexpanded jets in quiescent environments (Crist, Sherman & Glass 1966;Schetz et al 1967), transverse underexpanded jets form a complex system of expansion and shock waves (referred to as the barrel shock) as the jet expands into the crossflow.…”

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confidence: 94%

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

2015

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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: 94%

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

2015

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“…where the total temperature of the flow, T t , is different from the ambient reference temperature, T r , narrow linewidth lasers can be tuned to select a temperature-or pressureindependent absorption linewidth of iodine [22,38]. The selected absorption line determines the temperature dependency of the Boltzmann population fraction responsible for the fluorescence signal [52], thereby eliminating the confounding thermodynamic influence on the concentration measurements [38,44,[53][54][55]. However, despite this solution, iodine LIF measurements of concentration are still commonly performed using narrow linewidth laser at excitation wavelengths with known temperature sensitivity, in which temperature variations were simply assumed to be negligible, without reporting a detailed sensitivity analysis [23,46,56,57].…”

Section: Introductionmentioning

confidence: 99%

Confounding effects of temperature in laser-induced fluorescence concentration measurements with iodine vapor

Karthick¹,

Cukurel²,

Jacobi³

2020

Meas. Sci. Technol.

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Laser Induced Fluorescence (LIF) provides a non-invasive, quantitative measurement of fluorescent tracers in complex mixing flows. The common availability of broad linewidth lasers and their use with iodine vapor tracers raises a significant concern about confounded tracer concentration measurements, due to the strong dependence of iodine fluorescence on both tracer concentration and flow temperature. We model the sensitivity of iodine fluorescent response to temperature fluctuations, especially for flows with significant temperature contrasts to ambient conditions, and establish a temperature uniformity requirement that bounds the relative error in tracer concentration measurements. We show that in a conventional laboratory setup, in order to bound the measured concentration error to about 5%, the relative temperature fluctuations in iodine LIF must be approximately an order of magnitude smaller than the desired measurement resolution of relative concentration fluctuations. Iodine LIF should thus be employed with great caution.

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“…Thus the optimisation of the fuel injection scheme is an essential aspect in the development of a supersonic combustor and this provides the motivation for the present work. Earlier works involved the injection of fuel either perpendicular or oblique to the main stream (1)(2)(3)(4)(5)(6) . Though high penetration and mixing are achieved through perpendicular injection, the associated total pressure losses are quite large.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of the role of struts in high speed mixing

Desikan

Kurian

2013

Aeronaut. j. (1968)

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This paper presents the experimental results of the role of struts in supersonic mixing. Experiments were carried out with novel strut configurations to show their capabilities on mixing with reasonable total pressure losses. The performances were compared with the Baseline Strut configurations (BSPI and BSNI). The analysis presented includes the mixing quantifications using Mie scattering signature, flow field visualisation, measurement of wall static pressure and the total pressure loss calculations. The results clearly demonstrated that the proposed strut configurations achieved increased mixing (7-8%) compared to BSPI with increase in total pressure loss (2%). On the other hand, when compared with BSNI, the mixing performance was found to be decreased by 6% with reduced total pressure loss (12%).

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Experimental investigation of angled injection in a compressible flow

Cited by 11 publications

References 9 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

Confounding effects of temperature in laser-induced fluorescence concentration measurements with iodine vapor

Experimental investigation of the role of struts in high speed mixing

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