ANALYSIS OF THE HEAT-TRANSFER COEFFICIENT IN A TURBULENT PARTICLE PIPE-FLOW

A Eulerian-Lagrangian mathematical model is used to predict the average heat transfer coefficient at the inner wall of a vertical pipe. Air flows within the pipe in a turbulent regime loaded with spherical glass particles of uniform size 70, 140 and ?200 mu m in diameter. The suspension flow is predicted by solving numerically the mass, momentum and energy equations for the continuous phase and the motion and energy equations for individual-particles The turbulence of the air flow is calculated by using a standard K-epsilon model and the dispersion of the particles is predicted by the Lagrangian stochastic deterministic model. The average heat transfer coefficient of the suspension is calculated for different Reynolds numbers, particle loading ratios and particle diameters. The results are compared viith experimental data published in the literature.