EXAMINATION OF FLUID-PARTICLE IN TURBULENT, NON-DILUTE, PARTICLE SUSPENSION FLOW

Theoretical modeling and experimental studies of particles suspended in fully developed turbulent water flow in a vertical pipe (I.D. = 18.4 cm) have been conducted. An analytical model has been developed to predict the stochastic motion of particles in a non-dilute turbulent suspension flow. The model, incorporates hydrodynamic interaction between particles over a range of particle volume loadings and turbulent particle Reynolds numbers.;Comparison of theoretical predictions to experimental observations of particle stochastic motion, in general, showed good agreement for both longitudinal and lateral directions in the water study. For dilute particle loadings the predicted particle velocity variance agreed with observation to better than ten percent for all cases. The predicted particle autocorrelations showed a slightly more rapid decrease than experimentally observed for the range of particle loadings studied. However, the predicted dispersions showed excellent agreement with experimental data for all particles over the range of particle loadings used. Comparison of predictions with limited experimental data of Snyder and Lumley for dilute suspensions in air showed equally good agreement.;Three series of experiments have been conducted to investigate the behavior of particles in non-dilute turbulent suspension flow, for two particle densities and two particle sizes, and for several particle volume loadings ranging from 0 to 1 percent. The mean free fall velocity of the particles was determined at these various particle volume loadings, and the phenomenon of cluster formation was observed. The precise volume loading which gives the maximum relative settling velocity was observed to depend on particle density and size. Turbulent drag coefficients at various volume loadings were compared with several models and correlations in the literature. Particle dispersion was found to be sensitive to particle volume loading, increasing to a maximum near 0.5% and decreasing thereafter as the loading was increased.