Evaporation and combustion of sprays

Large-Eddy Simulations (LES) of an evaporating two-phase flow in an experimental burner are performed using two different solvers, CDP from CTR-Stanford and AVBP from CERFACS, on the same grid and for the same operating conditions. Results are evaluated by comparison with experimental data. The CDP code uses a Lagrangian particle tracking method (EL) while the code AVBP can be coupled either with a mesoscopic Eulerian approach (EE) or with a Lagrangian method (EL). After a validation of the purely gaseous flow in the burner, liquid-phase dynamics, droplet dispersion and fuel evaporation are qualitatively and quantitatively evaluated for three twophase flow simulations. They are respectively referred as: CDP-EL, AVBP-EE and AVBP-EL. The results of the three simulations show reasonable agreement with experiments for the two-phase flow case. RésuméSimulations eulériennes et lagrangiennes aux grandeséchelles d'unécoulement diphasiqueévaporant Les simulations aux grandeséchelles (SGE) de l'écoulement diphasiqueévaporant dans un brûleur expérimental sont réalisées avec deux codes numériques différents, CDP du CTR-Stanford et AVBP du CERFACS, sur le même maillage et pour les mêmes points de fonctionnement. Les résultats obtenus sont validés par comparaison avec des données expérimentales. Le code CDP peutêtre coupléà une méthode de suivi Lagrangien de la phase liquide (EL). Le code AVBP peut soitêtre coupléà une méthode mésoscopique Eulérienne (EE), soità une méthode de suivi Lagrangien (EL). Après validation de l'écoulement purement gazeux dans le brûleur, la dynamique de la phase liquide, la dispersion et l'évaporation du carburant sontévaluées qualitativement et quantitativement pour trois simulations diphasiques dénotées respectivement : CDP-EL, AVBP-EE et AVBP-EL. Les résultats obtenus par les trois simulations sont en accord raisonable avec l'expérience pour l'écoulement diphasique.

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“…In the CDP-EL solver, this effect is modeled by the multiplicative correction for heat and mass transfer [18].…”

Section: Evaporation Modelsmentioning

confidence: 99%

Eulerian and Lagrangian Large-Eddy Simulations of an evaporating two-phase flow

Senoner

Sanjosé

Lederlin

et al. 2009

Comptes Rendus. Mécanique

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“…The dispersed phase must have infinitely small particle size for this model to be quantitatively correct. That is, the LHF condition can be regarded as a limiting case of the spray composed of infinitely small droplets [5,8]. Compared with the LHF model, the SF model is a more logical approach in studying spray behaviour since the effect of finite transport rate between two phases is included in the analysis.…”

Section: Spray Modelmentioning

confidence: 99%

“…Because some assumptions may be introduced in normal pressure environment, the numerical simulation becomes easier than in the case for high pressure. Aggarwal [3] and Faeth [4,5] comprehensively reviewed the studies on the evaporation and combustion of spray.…”

Section: Introductionmentioning

confidence: 99%

Numerical modelling of unsteady spray behaviour in moderately high-pressure regime

Wang

Baek

2007

Combustion Theory and Modelling

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The present study is mainly motivated to develop an unsteady computational code that simulates a transient behaviour of the spray injected into a moderately high-pressure environment. The moderately high-pressure regime is introduced to minimize some of the complexities that arise from considering the high pressure. In order to represent the spray development, the DDM (discrete droplet model), which is often identified as the PSIC (particle-source-in-cell) model, is employed among the SF (separate flow) models. Here, the Eulerian-Lagrangian formulation is used to analyse the two-phase interactions. For an accurate prediction of droplet evaporation rate in a high-pressure environment, a proper highpressure evaporation model is applied using thermodynamic and phase equilibrium conditions. Also, the effects of high pressure as well as high temperature are considered in the calculation of liquid and gas properties. Throughout the numerical simulation, a transient thermo-fluid mechanical behaviour of spray in a high-pressure environment is traced and visualized while its physical meaning is discussed in comparison with the case for normal pressure. Regarding the evaporation of spray, the effect of interactions between droplets is examined in comparison with the case for single droplet.

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“…The vaporization rate is then given by the rate of mass diffusion of droplet species into the surrounding gas. This rate is computed by assuming that the drop is immobile with corrections applied to take into account convection due to the relative velocity between the drop and its surrounding [8]. Details of this model will be given when we described the SDROP code in Section 5.…”

Section: Surface Equilibrium Mass Diffusion Driven Corrected For Comentioning

confidence: 99%