NUMERICAL COMPUTATION OF TURBULENT GAS-SOLID PARTICLE FLOW IN A 90-DEGREES BEND

A numerical computation of the LDV results of Kliafas and Holt is repo rted for a turbulent gas-solid particle flow in a square-sectioned 90 degrees bend. A Eulerian model with generalized Eulerian solid surface boundary conditions for the particulate phase is employed. In the mom entum balance equation, the particulate-phase momentum exchanges with solid walls are included. The turbulent closure is effected by using t he gas-phase RNG-based k-epsilon turbulence model and the particulate turbulence diffusivity is related to the turbulent viscosity of the ga s phase. Comparisons are made with experimental data for the mean stre amwise velocities of both phases, the streamwise turbulence intensity of the gas phase, and the particulate concentration distribution in th e bend. The localized high particulate concentration near the outer cu rve of the bend that occurs at large Stokes number is accurately predi cted. Empirical computational evidence is presented for a relaxation o f the minimum particle number density required to allow the use of a c ontinuum model.