Numerical Analysis of Heat and Mass Transfer Problem in Laminar Flow(Part II:Heat Transfer and Fluid Mechanics for Laminar Multiphase Flow with its Variable Properties in Circular Tube)

摘要

The equations governing a gaseous solid suspension flow in a uniformly headed circular tube, where a large variation of gas-phase properties occurs, are solved by using the orthogonal collocation method. Results of the computations are illustrated for air-graphite system which downflows gravitationally. It is shown that more than ten internal radial collocation points are necessary to get the convergent field variables such as velocities, loading ratio. Comparison of the multiphase flows with their consant/variable properties is summarized as follows: (1) The axial velocities of particulate and gas phases with the variable proprieties are accelerated at the center of the pipe and retarded in the vicinity of the wall compared with those with the constant proprieties. (2) The profiles of loading ratio for the former are much lower than the latter in the downstream. (3) Nusselt number and static pressure increase as the inlet loading ratio increases and heat flux at the wall decreases.