During the past year the main object of our work has been to refine our model for fully developed turbulent flow in vertical tubes, improve the numerical algorithm for its solution, and explore its predictions over wide ranges of gas and particle fluxes.
For engineering purposes it is important
(a) to be able to predict the relation between the gas pressure gradient and the fluxes of gas and particles, over wide ranges of these fluxes, and for tubes of widely varying diameters, and
(b) to be able to predict the cross-sectional profiles of particle concentration, and the velocities of both particles and gas, and hence deduce quantities important for chemical reactions, such as residence time distributions.
In this Annual Report we demonstrate that the model meets both these requirements and test the agreement between its predictions and some limited experimental data. In order to establish confidence in its predictive capability it is now important to generate experimental data over as wide as possible a range of operating conditions. We hope that a suitable body of results will be generated by a related experimental exploration of riser flow, to be initiated by IFPRI.