Modeling subgrid scale mixture fraction variance in LES of evaporating spray

• Published in: Combustion and flame Vol. 146; no. 4; pp. 635 - 648
• Main Authors: Pera, Cécile, Réveillon, Julien, Vervisch, Luc, Domingo, Pascale
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2006; Elsevier
• Subjects: COMPUTERIZED SIMULATION; Direct numerical simulation; Engineering Sciences; EVAPORATION; Fluids mechanics; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; Large eddy simulation; MATHEMATICAL MODELS; Mechanics; Nonpremixed flames; Spray; SPRAYS; TURBULENCE; Nonpremixed flames; Large eddy simulation; Spray; Direct numerical simulation; Large eddy simu; Spray Nonpremix; Direct numerica
• ISSN: 0010-2180; 1556-2921
• DOI: 10.1016/j.combustflame.2006.07.003

Simulations of a dilute spray evaporating in spatially decaying homogeneous turbulence are performed. An Eulerian description of the flow is adopted, while the behavior of the discrete liquid phase is captured using Lagrangian modeling. Time and length scales of the continuous carrier phase are fully simulated and by varying the properties of the modeled spray, a database of spray carrier phase direct numerical simulation (CP-DNS) is obtained. The CP-DNS is then filtered on a coarse grid to conduct a priori tests of subgrid scale (SGS) closures. The objective is to provide methods for approximating the level of SGS mixture fraction variance in large eddy simulation (LES) of fuel spray turbulent combustion. Direct estimation of the variance from the scales resolved in LES is first discussed. Then, the solving of a balance equation to get the variance is addressed, with closures for the scalar dissipation rate and the correlation between vapor source and mixture fraction. From the results, a procedure to couple spray evaporation with SGS turbulent combustion modeling emerges.