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stream thus i predic chara the g partic distrib can b which Eaton demo way, in reg large-1 Copyright @ 1998 by ASME RODUCTION wo-phase flows involving solid particles carried by a gas are common in many engineering applications and it is mportant for the practicing engineer to have means to t their relevant characteristics. These required flow cteristics are typically the mean velocities of each phase, as and the particles, and the concentration of the ulate phase which will indicate how the particles are uted. It is now known that some of these type of flows e very complex in the details and the mechanisms by particles respond to the fluid turbulence; the reviews by and Fessler (1994) and Crowe et al. (1996) clearly nstrate that particles are dispersed in a non-homogeneous even in homogeneous turbulence, and tend to concentrate ions of low instantaneous vorticity thus responding to the scale coherent structures in the turbulent motions. Such model equations which are composed of the ensemble-averaged momentum and continuity equations for each phase in conjunction with transport equations for k and which are% used to characterize the effects of turbulence. The equations are discretised using a finite-volume technique and the resulting equations are solved in an iterative algorithm which is based on the pressure-correction scheme. Central to the two-phase model used, in particular the model for the effects of turbulence, is the assumption of simple algebraic relations between the local turbulence quantities of the continuous and dispersed phases. This assumption then facilitates the correlation between the turbulent stresses for the dispersed phase and those of the continuous phase which in turn are related by an eddy viscosity to the rates of strain in that phase. The above assumption requires the prescription of response functions correlating the turbulence energies (C), th