Numerical Simulation of Turbulent Spray Flows Using Transported PDF Methods

This paper presents a numerical study of a turbulent acetone spray flow, where the gas phase model includes a transported joint probability density function (PDF) of the gas phase velocity and the mixture fraction. This approach greatly benefits from the fact that the spray evaporation rate appears in closed form, and no additional modeling is required, whereas the molecular mixing requires closure. This is achieved through use of the extended interaction-by-exchange-with-the-mean (IEM) model with an additional term to account for spray evaporation. The dispersed liquid phase is described through a Lagrangian discrete parcel method with a point-source approximation. For droplet evaporation, an equilibrium model is compared with a more advanced non-equilibrium model. Numerical results of droplet size as well as mean and fluctuating velocities are presented and discussed in comparison with experimental results from the literature, and good agreement is observed. The non-equilibrium model predicts somewhat slower spray evaporation compared with the equilibrium model.