Characterization of a Dual-Mode Scramjet via Stereoscopic Particle Image Velocimetry

Rice, Brian

doi:10.18130/v38v6p

Cited by 4 publications

(5 citation statements)

References 44 publications

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“…Initially, a continuous re-cycling / rescaling procedure was used to introduce resolved turbulent fluctuations at the isolator inflow, following Boles and Edwards [34]. As discussed later in this paper (see also [23]), this approach led to over-mixing of reactants downstream of the fuel injector, an effect likely due to marginal mesh resolution within the thin isolator boundary layers. This approach was then replaced in favor of an ad hoc procedure which forced the isolator region of Configuration C to operate in RANS mode before switching to hybrid LES/RANS further downstream (see Figure 3).…”

Section: Methodsmentioning

confidence: 99%

“…Experimental data was gathered from the SCF experiments using various non-intrusive measurement techniques, such as coherent anti-Stokes Raman spectroscopy (CARS) (George Washington University), OH planar laser induced fluorescence (OH-PLIF) (NASA Langley, University of Calgary, and George Washington University), stereoscopic particle image velocimetry (SPIV) (University of Virginia), focusing Schlieren (University of Virginia and Tohoku University) and tunable diode laser spectroscopy (Stanford University, University of Virginia). The present study focuses on OH-PLIF [22], wall pressure [23], SPIV [23] and CARS [24] data taken from Configuration C at an equivalence ratio of 0.17; comparisons with other diagnostic data for this configuration can be found in [25][26][27].…”

Section: Facilitymentioning

confidence: 99%

“…Cases B-1 and B-2 use laminar chemistry and PaSR-SS, respectively, and use a RANS isolator inflow. Results from other cases may be found in [23]. Time averages shown were obtained from 350 discrete snapshots extracted over the averaging period.…”

Section: Comparisons With Experimental Data and Model Assessmentmentioning

confidence: 99%

See 2 more Smart Citations

Turbulence/chemistry interactions in a ramp-stabilized supersonic hydrogen–air diffusion flame

Fulton

Edwards

Cutler

et al. 2016

Combustion and Flame

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Hybrid large-eddy / Reynolds-averaged Navier-Stokes simulations of turbulence / chemistry interactions occurring within a ramp-injected, hydrogen-fueled scramjet combustor are presented in this work. The experimental geometry is one of several studied at the Universty of Virginia as part of the National Center for Hypersonic Combined Cycle Propulsion and consists of an isolator, a combustor, and an extender section. Data collected includes coherent anti-Stokes Raman spectroscopy (CARS) measurements of major species composition and temperature at several streamwise planes, stereoscopic particle image velocimetry (PIV) measurements, hydroxyl planar-induced fluorescence (OH-PLIF) imagery, wall pressure distributions, and line-of-sight profiles of temperature and water concentration obtained using tunable diode laser spectroscopy (TDLAS). This paper focuses on an equivalence ratio of 0.17, which does not produce enough heat release to force a shock train into the isolator. The computational methods utilize a hybrid fourth-order central-difference / upwind strategy to enable accurate resolution of turbulent structures and employ a nine-species hydrogen oxidation mechanism. Generally accurate predictions of temperature, velocity, and nitrogen mole fraction are achieved through a 'laminar chemistry' assumption for the filtered species production rates, though results do improve slightly with the use of a simple turbulence / chemistry subgrid closure model. The predictions are most sensitive to the choice of isolator inflow boundary condition, with the use of a recycling / rescaling technique to sustain turbulent fluctuations resulting in an 'over-mixing' effect immediately downstream of the fuel injector. Turbulence-chemistry interactions in the flameholding region are examined from the standpoint of laminar flamelet theory. A region of high scalar dissipation rate, coincident with the breakdown of the fuel plume and the interaction of a reflected shock wave with the plume, inhibits flame propagation, forming a 'hole' in the flame. Advection of cooler fluid downstream into regions of moderate scalar dissipation enlarges the 'hole', but eventually the flame reconnects. These results point to one potential disadvantage of fuel-air mixing technologies that enhance axial vorticityeven if conditions for combustion are favorable, high strain rates generated by the interaction and breakdown of vortex pairs can lead to flame suppression.

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Section: Methodsmentioning

confidence: 99%

Section: Facilitymentioning

confidence: 99%

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Turbulence/chemistry interactions in a ramp-stabilized supersonic hydrogen–air diffusion flame

Fulton

Edwards

Cutler

et al. 2016

Combustion and Flame

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show abstract

“…with tomographic PIV [24,25]. Rice [26] extended the application of SPIV to the dual-mode combustion regime, finding the average velocity fields to be within a 10% difference when compared to hybrid LES/RANS predictions downstream. RMS velocities were however overpredicted.…”

Section: Papermentioning

confidence: 99%

High-resolution PIV for characterization of the inflow to a cavity flameholder

Lieber

Goyne

Gibbons

2020

Meas. Sci. Technol.

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A methodology for the implementation of high-resolution, two-component, two-dimensional particle image velocimetry (PIV) in a high-speed, high-enthalpy flow is presented and demonstrated. The objective is to resolve the finer scales of combusting flows at high subsonic Mach numbers for accurate boundary conditions quantification for direct numerical simulations. A three-pronged approach consists of finding a near-optimum setup specific to the experiment, enhancing the raw signal with a novel filter for high-speed flows based on a logarithmic transform, and quantifying uncertainties. The methodology effectiveness is demonstrated with synthetic PIV, real PIV, and comparison with numerical simulations.

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“…As a point of comparison, the combustion efficiency of the UVaSCF is calculated for The combustion efficiency is calculated from TDLAT and SPIV measurements for both the scram-mode and ram-mode, as seen in (f) Figure 4.38: Water vapor number density from TDLAT measurement, axial velocity from SPIV measurement [60], and water vapor flux for the scram-mode (first column) and ram-mode (second column).…”

Section: Combustion Efficiencymentioning

confidence: 99%

Development of Tunable Diode Laser Absorption Tomography and Application to Scramjet Engines

Busa

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Scramjets are an appealing alternative to traditional rocket engines for many applications such as access to space, long-range strike missile capabilities, and civilian transport. Their advantages over rockets and traditional jet engines include a stationary flow path with no moving parts and higher payload capacity due to their airbreathing operation. A major hindrance to the maturation of scramjet technology is the high-cost and high-risk associated with flight testing. Computational fluid dynamics (CFD) simulations are a promising alternative to flight testing, but much of the complex flow physics present in scramjet engines are not well understood, making the modeling of these high-enthalpy, supersonic, combusting, and three-dimensional flows extremely challenging. Ground testing of scramjet model flow paths allows for experimental measurements of key variables, such as temperature and species number density, in controlled experimental environments. These measurements are guided by preliminary CFD results while also serving to validate the advanced state-of-the-art computational models. This symbiotic relationship between ground test experiments and computational models brings us closer to the realization of operational scramjet technology.Harsh flowfields, such as those found within a scramjet, can present great difficulties for conventional in-stream diagnostics. The high speed, high enthalpy, combusting flowfields make probing the flow very challenging. Optical diagnostics, such as tunable diode laser (TDL) techniques, have an advantage in these harsh flowfields over their mechanical counterparts due to their non-intrusive nature. No hardware comes in contact with the flow itself, and therefore the integrity of the diagnostic is preserved and the flow is undisturbed. Traditional implementations of TDL, such as Tunable Diode Laser Absorption Spectroscopy (TDLAS), are indeed non-intrusive, but are limited by their path-integrated line-of-sight (LOS) nature. The harsh flowfields of a scramjet are highly three-dimensional and thus an optical diagnostic technique capable of producing spatially resolved measurements is required. Tunable Diode Laser Absorption Tomography (TDLAT) is a non-intrusive optical technique which combines TDLAS and computed tomography (CT) to produce a 2-D spatially resolved measurement of two key combustion diagnostic properties: temperature and species number density. Several hundred LOS TDLAS measurements are collected for each experiment and are subsequently reconstructed utilizing a tomographic post-processing algorithm. The TDLAT measurement results in highly resolved 2-D temperature and species number density distributions of the flowfield at the probed measurement plane.The work presented herein describes the development of the TDLAT technique, building upon earlier proof-of-concept demonstrations. Application of the TDLAT diagnostic to two scramjet-relevant ground test facilities is presented and the insight gained from the resulting 2-D distributions is discussed. Of gr...

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Characterization of a Dual-Mode Scramjet via Stereoscopic Particle Image Velocimetry

Cited by 4 publications

References 44 publications

Turbulence/chemistry interactions in a ramp-stabilized supersonic hydrogen–air diffusion flame

Turbulence/chemistry interactions in a ramp-stabilized supersonic hydrogen–air diffusion flame

High-resolution PIV for characterization of the inflow to a cavity flameholder

Development of Tunable Diode Laser Absorption Tomography and Application to Scramjet Engines

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