A stochastic breakup model for Large Eddy Simulation of a turbulent two-phase reactive flow

Jones, W.P.; Marquis, A. J.; Noh, D.

doi:10.1016/j.proci.2016.06.033

Cited by 6 publications

(4 citation statements)

References 23 publications

(30 reference statements)

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“…The temporal evolution of the joint sgs-pdf is represented by an ensemble of N stochastic fields, with each field involving the N s scalars, namely n (x, t) with 1 ≤ n ≤ N and 1 ≤ ≤ N s . In the present work the Itô formulation of the stochastic integral is adopted and the influence of the sgs fluctuations of the dispersed phase is neglected (Jones et al 2016).…”

Section: Stochastic Field Methodsmentioning

confidence: 99%

“…The secondary breakup model used is the improved version of Noh et al (Jones et al 2016) of the previously proposed model by Jones and Lettieri (2010). The rate of change of the droplet number Ṅ in Eq.…”

Section: Droplet Breakupmentioning

confidence: 99%

“…The process will continue until the droplet radius becomes smaller than r c , the number of droplets generated in the breakup m(r 0 ) is computed as the sum of the number of daughter particles. The interested reader is referred to Jones et al (2016), Noh (2016) for further details.…”

Section: Droplet Breakupmentioning

confidence: 99%

See 2 more Smart Citations

Large Eddy Simulation of an Ethanol Spray Flame with Secondary Droplet Breakup

Gallot-Lavallée

Jones

Marquis

2021

Flow Turbulence Combust

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A computational investigation of three configurations of the Delft Spray in Hot-diluted Co-flow (DSHC) is presented. The selected burner comprises a hollow cone pressure swirl atomiser, injecting an ethanol spray, located in the centre of a hot co-flow generator, with the conditions studied corresponding to Moderate or Intense Low-oxygen Dilution (MILD) combustion. The simulations are performed in the context of Large Eddy Simulation (LES) in combination with a transport equation for the joint probability density function (pdf) of the scalars, solved using the Eulerian stochastic field method. The liquid phase is simulated by the use of a Lagrangian point particle approach, where the sub-grid-scale interactions are modelled with a stochastic approach. Droplet breakup is represented by a simple primary breakup model in combination with a stochastic secondary breakup formulation. The approach requires only a minimal knowledge of the fuel injector and avoids the need to specify droplet size and velocity distributions at the injection point. The method produces satisfactory agreement with the experimental data and the velocity fields of the gas and liquid phase both averaged and ‘size-class by size-class’ are well depicted. Two widely accepted evaporation models, utilising a phase equilibrium assumption, are used to investigate the influence of evaporation on the evolution of the liquid phase and the effects on the flame. An analysis on the dynamics of stabilisation sheds light on the importance of droplet size in the three spray flames; different size droplets play different roles in the stabilisation of the flames.

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Section: Stochastic Field Methodsmentioning

confidence: 99%

Section: Droplet Breakupmentioning

confidence: 99%

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Large Eddy Simulation of an Ethanol Spray Flame with Secondary Droplet Breakup

Gallot-Lavallée

Jones

Marquis

2021

Flow Turbulence Combust

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“…[89][90][91]). The LES-SF approach has been recently developed to include sub-grid fluctuations of quantities related to multi-phase interactions such as evaporation [92] and secondary breakup [93,93], allowing for a more comprehensive description of the physics of real burners. One of the main advantages of transported PDF methods is that the chemical source term explicitly appears in the formulation and therefore no closure is required.…”

Section: Turbulent Combustion Modelsmentioning

confidence: 99%

Turbulent Combustion Modelling and Experiments: Recent Trends and Developments

Giusti

Mastorakos

2019

Flow Turbulence Combust

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The development of better laser-based experimental methods and the fast rise in computer power has created an unprecedented shift in turbulent combustion research. The range of species and quantities measured and the advent of kHz-level planar diagnostics are now providing great insights in important phenomena and applications such as local and global extinction, pollutants, and spray combustion that were hitherto unavailable. In simulations, the shift to LES allows better representation of the turbulent flow in complex geometries, but despite the fact that the grid size is smaller than in RANS, the push towards realistic conditions and the need to include more detailed chemistry that includes very fast species and thin reaction zones emphasize the necessity of a sub-grid turbulent combustion model. The paper discusses examples from current research with experiments and modelling that focus on flame transients (self-excited oscillations, local extinction), sprays, soot emissions, and on practical applications. These demonstrate how current models are being validated by experimental data and the concerted efforts the community is taking to promote the modelling tools to industry. In addition, the various coordinated International Workshops on non-premixed, premixed, and spray flames, and on soot are discussed and some of their target flames are explored. These comprise flames that are relatively simple to describe from a fluid mechanics perspective but contain difficult-to-model combustion problems such as extinction, pollutants and multi-mode reaction zones. Recently, swirl spray flames, which are more representative of industrial devices, have been added to the target flames. Typically, good agreement is found with LES and some combustion models such as the progress variable-mixture fraction flamelet model, the Conditional Moment Closure, and the Transported PDF method, but predicting soot emissions and the condition of complete extinction in complex geometries is still elusive.

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