Date of Award
Doctor of Philosophy
This thesis represents the initial step in a more rigorous approach to the study of the hydrodynamic and heat transfer behaviour of gas-solids suspension flows. General Probabilistic Multiphase flow equa- tions were developed and used as the basis for analyzing pressure drops and pipe wall to suspension heat transfer coefficients meas- ured in dilute, vertical, fully developed suspension flows. Hydrody- namic experiments were carried out with sand ((')d(,p) = 172, 249 (mu)m) and glass bead ((')d(,p) = 65 (mu)m) suspensions in a 12 m high, 20 mm ID transport line installation designed to allow pressure drops, solids and gas flowrates and mean solids concentrations to be measured. Heat transfer experiments were carried out with 249 (mu)m sand suspen- sions in the same installation with a modified test section. A thinned-walled stainless steel pipe was heated electrically in order to provide a constant heat flux from the test section wall to the suspension flowing inside.;The general equation analysis showed pressure drops in dilute vertical suspension flows to be dependent on particle-wall coeffi- cients of restitution and the local solids concentration and velocity in the vicinity of the pipe wall. The lack of information available on solids concentration and velocity profiles prevented the develop- ment of a final pressure drop expression in terms of mean values, averaged across the pipe cross-section. The hydrodynamic results did nevertheless suggest that reduced concentration and velocity profiles were independent of the mean solids concentration in dilute flows. This conclusion and an asymptotic analysis of the energy equations allowed the development of a general expression for the variation of fully developed heat transfer coefficients as a function of loading ratio. Heat transfer coefficient ratios were predicted to either increase, decrease, or pass through a minimum and then increase depending on the relative magnitudes of three coefficients which are fully determined by the hydrodynamics of the system. The general predicted variation was confirmed experimentally and numerical values of the hydrodynamic coefficients were determined.
Muzyka, Douglas Walter, "The Use Of Probabilistic Multiphase Flow Equations In The Study Of The Hydrodynamics And Heat Transfer In Gas-solids Suspensions" (1985). Digitized Theses. 1461.