Comparative study of Euler/Euler and Euler/Lagrange approaches simulating evaporation in a turbulent gas-liquid flow
This study deals with the Reynolds-averaged Navier-Stokes simulation of evaporation in a turbulent gas-liquid flow in a three-dimensional duct, focussing on the results obtained by a four-equation turbulence model within the framework of the Ether/Euler approach for multiphase flow calculations: in addition to the two-equation k-epsilon model describing the turbulence of the continuous (C) phase, the computational model employs transport equations for the turbulence kinetic energy of the disperse (D) phase and for the velocity covariance q =  (D). In the present study, the evaporation model according to Abramzon and Sirignano (Int. J. Hens glass Transfer 1989; 32:1605-1618) has been extended by introducing an additional transport equation for a newly defined quantity (a) over bar defined as the phase-interface surface fraction. This allows the change in the drop diameter to be quantified in terms of a probability density function. The source term in the equation describing the dynamics of the volumetric fraction of the dispersed phase alpha(D) is related to the evaporation time scale tau(Gamma). The performance of the new model is evaluated by performing a comparative analysis of the results obtained by simulating a polydispersed spray in a three-dimensional duct configuration with the results of the Eider/Lagrange calculations performed in parallel. Prior to these calculations, some selected (solid) particle-laden flow configurations were computationally examined with respect to the validation of the background, four-equation, eddy-viscosity-based turbulence model. Copyright (c) 2008 John Wile), & Sons, Ltd.
euler/euler and euler/lagrange approaches four-equation turbulence model gas/liquid flow liquid evaporation