Simultaneous gas density and fuel concentration measurements in a supersonic combustor using laser induced breakdown

Do, Hyungrok; Carter, Campbell D.; Liu, Qili; Ombrello, Timothy; Hammack, Stephen D.; Lee, Tonghun; Hsu, Kuang–Yu

doi:10.1016/j.proci.2014.07.043

Cited by 70 publications

(9 citation statements)

References 13 publications

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“…Fuel concentration measurements are also available at a limited number of stations within the cavity flameholder. These measurements were obtained using laser-induced breakdown spectroscopy as described in [11]. Previous computational efforts [9] for this configuration considered only aerodynamic flowfield simulations that neglected the mixing processes associated with fuel injection.…”

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confidence: 99%

Hybrid Reynolds-Averaged/Large-Eddy Simulation of a Scramjet Cavity Flameholder

Baurle

2017

AIAA Journal

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.J055339Steady-state and scale-resolving simulations have been performed for flow in and around a model scramjet combustor flameholder. Experimental data available for this configuration include velocity statistics obtained from particle image velocimetry as well as a limited number of scalar measurements using laser-induced breakdown spectroscopy. Several turbulence models were used for the steady-state Reynolds-averaged simulations, which included both linear and nonlinear eddy viscosity models. The scale-resolving simulations used a hybrid Reynoldsaveraged/large-eddy simulation strategy that is designed to be a large-eddy simulation everywhere except in the inner portion (log layer and below) of the boundary layer. Hence, this formulation can be regarded as a wall-modeled largeeddy simulation. This effort was undertaken to not only assess the performance of the hybrid Reynolds-averaged/ large-eddy simulation modeling approach in a flowfield of interest to the scramjet research community but also to begin to understand how this capability can best be used to augment standard Reynolds-averaged simulations. The numerical errors were quantified for the steady-state simulations and at least qualitatively assessed for the scaleresolving simulations before making any claims of predictive accuracy relative to the measurements. The steady-state Reynolds-averaged results displayed a high degree of variability when comparing the flameholder fuel distributions obtained from each turbulence model. This prompted the consideration of applying the higher-fidelity scale-resolving simulations as a surrogate "truth" model to calibrate the Reynolds-averaged closures in a nonreacting setting before their use for the combusting simulations. In general, the Reynolds-averaged velocity profile predictions at the lowest fueling level matched the particle imaging measurements almost as well as was observed for the nonreacting condition. However, the velocity field predictions proved to be more sensitive to the flameholder fueling rate than was indicated in the measurements.

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confidence: 99%

Hybrid Reynolds-Averaged/Large-Eddy Simulation of a Scramjet Cavity Flameholder

Baurle

2017

AIAA Journal

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“…In particular, Tuttle et al [6] recently used particle image velocimetry to measure velocity and vorticity fields for non-reactive and reactive cavity with different fuel flow rates and Do et al [12] have provided an estimation of ethylene concentration. In the experimental set-up, the air flow is accelerated through a nozzle to reach supersonic speed and enters the isolator at nominal Mach 2, with a total temperature and pressure of 589 K and 483 kPa, respectively.…”

Section: Configuration Descriptionmentioning

confidence: 99%

Analysis of combustion modes in a cavity based scramjet

Ruan

Domingo

Ribert

2020

Combustion and Flame

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Large eddy simulations (LES) of non reactive and reactive flows in a cavity-based scramjet combustor configuration from the U.S Air Force Research Laboratory (AFRL) are performed. These simulations feature a 22 species and 206 reactions chemical scheme for ethylene/air. The ability of LES to reproduce the main features found in the experiment is first emphasised such as the average velocity field and the stability of the combustion for the case studied. The influence of the mesh resolution and of the thermal wall condition on the simulation results is also investigated along with the soundness of the use of a laminar model for the filtered source terms. The results of the simulations with the finest grid (resolution of 100 micrometers in the flame region) are then employed to gain understanding in the flame dynamics. This reactive simulation shows the persistence of the two recirculation zones already present in the non reactive flow. The globally high temperature into the cavity helps to sustain a reactive zone located in the mixing layer above the cavity. Combustion first occurs in a diffusion dominated regime followed by the efficient burning of a well stirred mixture (rich then lean). A significant diffusion dominated burning is also found inside the cavity. The links between the residence time inside the cavity and the efficiency of the combustion are explored along with the velocity/heat release correlation.

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“…When the assumptions of local thermal equilibrium (LTE) and optically thin plasma are satisfied [80,81], the intensities of the spectral emission lines of the plasma can be used to determine the equivalence ratio quantitatively. In most of the previous studies, the ratios of certain spectral lines of LIBS could be used to correlate and quantify mixture fraction including H (656 nm)/O (777 nm) [82][83][84], H (656 nm)/N (568 nm) [85], C (833 nm)/N (744 nm) [86], C (833 nm)/O (777 nm) [86], C (711 nm)/(N (745 nm)+O (777 nm)) [87], and C 2 (516.5 nm)/CN (388 nm) [88].…”

Section: Femtosecond Laser-induced Breakdown Spectroscopy (Fs-libs)mentioning

confidence: 99%

A Review of Femtosecond Laser-Induced Emission Techniques for Combustion and Flow Field Diagnostics

Zhang

Liu

et al. 2019

Applied Sciences

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The applications of femtosecond lasers to the diagnostics of combustion and flow field have recently attracted increasing interest. Many novel spectroscopic methods have been developed in obtaining non-intrusive measurements of temperature, velocity, and species concentrations with unprecedented possibilities. In this paper, several applications of femtosecond-laser-based incoherent techniques in the field of combustion diagnostics were reviewed, including two-photon femtosecond laser-induced fluorescence (fs-TPLIF), femtosecond laser-induced breakdown spectroscopy (fs-LIBS), filament-induced nonlinear spectroscopy (FINS), femtosecond laser-induced plasma spectroscopy (FLIPS), femtosecond laser electronic excitation tagging velocimetry (FLEET), femtosecond laser-induced cyano chemiluminescence (FLICC), and filamentary anemometry using femtosecond laser-extended electric discharge (FALED). Furthermore, prospects of the femtosecond-laser-based combustion diagnostic techniques in the future were analyzed and discussed to provide a reference for the relevant researchers.

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Simultaneous gas density and fuel concentration measurements in a supersonic combustor using laser induced breakdown

Cited by 70 publications

References 13 publications

Hybrid Reynolds-Averaged/Large-Eddy Simulation of a Scramjet Cavity Flameholder

Hybrid Reynolds-Averaged/Large-Eddy Simulation of a Scramjet Cavity Flameholder

Analysis of combustion modes in a cavity based scramjet

A Review of Femtosecond Laser-Induced Emission Techniques for Combustion and Flow Field Diagnostics

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