A computational study of non-premixed flame extinction by water spray

Arias, Paul G.; Im, Hong G.; Narayanan, Priya; Trouvé, Arnaud

doi:10.1016/j.proci.2010.07.043

Cited by 20 publications

(10 citation statements)

References 17 publications

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“…As an additional simulation dataset, Case 2 was produced using the S3D, whose detailed numerical algorithms can be found in previous studies [26]. The configuration and boundary conditions are consistent as in Figure 1a.…”

Section: Computational Approach a Direct Numerical Simulationsmentioning

confidence: 99%

A flame particle tracking analysis of turbulence–chemistry interaction in hydrogen–air premixed flames

Uranakara

Chaudhuri

Dave

et al. 2016

Combustion and Flame

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Interactions of turbulence, molecular and energy transport coupled with chemistry play a crucial role in the evolution of flame surface geometry, propagation, annihilation and local extinction/re-ignition characteristics of intensely turbulent premixed flames. This study seeks to understand how these interactions affect flame surface annihilation of lean hydrogen-air premixed turbulent flames. Direct numerical simulations (DNS) are conducted with detailed reaction mechanism and transport properties for hydrogen-air flames, at different parametric conditions. Flame particle tracking (FPT) technique is used to follow specific flame surface segments. An analytical expression for the local displacement flame speed (S d ) of a temperature isosurface is considered and the contributions of transport, chemistry and kinematics on the displacement flame speed at different turbulence-flame interaction conditions are identified. In general, the displacement flame speed for the flame particles is found to increase with time for all conditions considered. This is because, eventually all flame surfaces and their resident flame particles approach annihilation by reactant island formation at the end of stretching and folding processes induced by turbulence. Principal curvature evolution statistics obtained using FPT suggest that these islands are ellipsoidal on average, enclosing fresh reactants. Further examinations show that the increase in S d is caused by the increased negative curvature of the flame surface and eventual homogenization of temperature gradients, as these reactant islands shrink due to flame propagation and turbulent mixing. Finally, the evolution of the normalized, averaged, displacement flame speed vs. stretch Karlovitz number was found to collapse on a narrow band, suggesting that a unified description of flame speed dependence on stretch rate may be possible in the Lagrangian description.

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Section: Computational Approach a Direct Numerical Simulationsmentioning

confidence: 99%

A flame particle tracking analysis of turbulence–chemistry interaction in hydrogen–air premixed flames

Uranakara

Chaudhuri

Dave

et al. 2016

Combustion and Flame

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“…Further information and discussion on the governing equations and the boundary conditions can be found in Refs. [15,24,17,14] and references therein.…”

Section: Navier-stokes Solvermentioning

confidence: 99%

“…Several past DNS works and analysis using DNS data have focused on non-premixed flame extinction in various environments [9][10][11][12][13][14][15][16][17]. Dependence of local extinction and reignition on the overall mixing in CO/H 2 non-premixed turbulent jet flames were studied using the one-dimensional turbulence model by Hewson and Kerstein [9].…”

Section: Introductionmentioning

confidence: 99%

“…Past work by our group was focused on flame extinction diagnostics in different flame extinction configurations: by convective cooling due to flame interactions with a cold wall [15], by thermal radiation losses due to high soot loading [16], by evaporative cooling due to water-spray [17]. Narayanan et al [18], have studied a Damköhler-number-based flame extinction criterion using large activation energy asymptotic (AEA) analysis and explored the extinction limits of laminar counter-flow diffusion flames as a function of flame stretch and radiant losses due to soot and gas-phase species.…”

Section: Introductionmentioning

confidence: 99%

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Direct numerical simulations of non-premixed ethylene–air flames: Local flame extinction criterion

Lecoustre

Arias

Roy

et al. 2014

Combustion and Flame

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a b s t r a c tDirect Numerical Simulations (DNS) of ethylene/air diffusion flame extinctions in decaying twodimensional turbulence were performed. A Damköhler-number-based flame extinction criterion as provided by classical large activation energy asymptotic (AEA) theory is assessed for its validity in predicting flame extinction and compared to one based on Chemical Explosive Mode Analysis (CEMA) of the detailed chemistry. The DNS code solves compressible flow conservation equations using high order finite difference and explicit time integration schemes. The ethylene/air chemistry is simulated with a reduced mechanism that is generated based on the directed relation graph (DRG) based methods along with stiffness removal. The numerical configuration is an ethylene fuel strip embedded in ambient air and exposed to a prescribed decaying turbulent flow field. The emphasis of this study is on the several flame extinction events observed in contrived parametric simulations. A modified viscosity and changing pressure (MVCP) scheme was adopted in order to artificially manipulate the probability of flame extinction. Using MVCP, pressure was changed from the baseline case of 1 atm to 0.1 and 10 atm. In the high pressure MVCP case, the simulated flame is extinction-free, whereas in the low pressure MVCP case, the simulated flame features frequent extinction events and is close to global extinction. Results show that, despite its relative simplicity and provided that the global flame activation temperature is correctly calibrated, the AEA-based flame extinction criterion can accurately predict the simulated flame extinction events. It is also found that the AEA-based criterion provides predictions of flame extinction that are consistent with those provided by a CEMA-based criterion. This study supports the validity of a simple Damköhler-number-based criterion to predict flame extinction in engineering-level CFD models.

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“…The soot model has been implemented into S3D, a compressible DNS code (Sankaran et al 2007;Arias et al 2011a) which employs an explicit 4th-order Runge-Kutta time integration (Kennedy et al 2000), coupled with an 8th-order central finite-differencing scheme (Kennedy and Carpenter 1994) to integrate the compressible form of the Navier-Stokes equations. Boundary conditions are treated using the Navier-Stokes characteristic boundary conditions (NSCBC) (Yoo et al 2005;Yoo and Im 2007a).…”

Section: Dns Considerations Using Momicmentioning

confidence: 99%

Development of High Fidelity Soot Aerosol Dynamics Models using Method of Moments with Interpolative Closure

Roy

Arias

Lecoustre

et al. 2014

Aerosol Science and Technology

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The method of moments with interpolative closure (MOMIC) for soot formation and growth provides a detailed modeling framework maintaining a good balance in generality, accuracy, robustness, and computational efficiency. This study presents several computational issues in the development and implementation of the MOMIC-based soot modeling for direct numerical simulations (DNS). The issues of concern include a wide dynamic range of numbers, choice of normalization, high effective Schmidt number of soot particles, and realizability of the soot particle size distribution function (PSDF). These problems are not unique to DNS, but they are often exacerbated by the high-order numerical schemes used in DNS. Four specific issues are discussed in this article: the treatment of soot diffusion, choice of interpolation scheme for MOMIC, an approach to deal with strongly oxidizing environments, and realizability of the PSDF. General, robust, and stable approaches are sought to address these issues, minimizing the use of ad hoc treatments such as clipping. The solutions proposed and demonstrated here are being applied to generate new physical insight into complex turbulence-chemistry-soot-radiation interactions in turbulent reacting flows using DNS.

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A computational study of non-premixed flame extinction by water spray

Cited by 20 publications

References 17 publications

A flame particle tracking analysis of turbulence–chemistry interaction in hydrogen–air premixed flames

A flame particle tracking analysis of turbulence–chemistry interaction in hydrogen–air premixed flames

Direct numerical simulations of non-premixed ethylene–air flames: Local flame extinction criterion

Development of High Fidelity Soot Aerosol Dynamics Models using Method of Moments with Interpolative Closure

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