JOINT GAS-PHASE VELOCITY-SCALAR PDF MODELING FOR TURBULENT EVAPORATING SPRAY FLOWS

摘要

The article proposes a joint gas-phase velocity-scalar probability density junction (PDF) model for turbulent spray flows. The joint gas-phase velocity-mixture fraction PDF transport equation for turbulent spray flows is derived and modeled. The simplified Langevin model and interaction-by-exchange-with-the-mean (IEM) model are extended to account for spray evaporation, and they close the PDF transport equation, which is solved by a Lagrangian Monte-Carlo particle method, and the droplet characteristics including heating, vaporization, and motion are solved by a Lagrangian droplet parcel method using the point-source approximation. A steady, two-dimensional, axi-symmetric, turbulent methanollair dilute non reacting spray flow without swirl is simulated using the present method. The results of the gas velocity obtained by the joint PDF method are in good agreement with experimental data, and the PDF method improves the simulation results obtained using a moment closure model.