| Though fluidized bed technology has been widely used in energy source, chemical engineering and other industrial fields, the understanding of fluidized bed is in a laggard place because of the complex mechanism and interaction among hydrodynamic, heat transfer andcombustion. The paper aimed at circulating fluidized bed(CFB) in order to study the phenomenon of flow of two phase flow;A set of cool experimental circulating fluidized bed device was designed, with which experiments were carried out to determine the distribution of pressure drop and solid phase's concentration in the direction of axis. And also the device was simulating. The results of cold - flow model test indicate that pressure drop rises with increasing air quantity and solids quantity respectively, however, much more air quantity will make pressure drop minish in the same height position;The average concentration of granule minishes with increasing air quantity, and rises with increasing solids quantity in the same height position;The inhomogeneity of distribution of the average granule concentration minishes with increasing air quantity, and rises with increasing the granule quantity. In the same time, the paper used simulating and calculating busibess software of large scale fluid engineering(Fluent) to simulate and study the experimental device, and this paper combine the mechanical drawing software Solidworks and Gambit which is pretreatment software of simulating and calculating of fluid to plot out cell, and also adopted the two-fluid of gas and solid of Eulerian model, so it conquered the limitation of unideal simulating results because of the difficulty of geometrical modelling and the unhappy choice of model. simulation adopted the unsteady and segregated resolver,it can make results bring near with practice. Firstly,single bubble in the dense zone of fluidized bed was simulated , and it shows the dynamical process of formation, movement upward, grown and eruption of bubble. The whole flow field was simulated and the results shows that it still can appear the different axial distribution of voidage due to different primary solids quantity, even if it has the same apparent velocity of air and circulating quantity of solids, which shows that it is far from exact ,only to postulate the same apparent velocity of air and circulating quantity of solids studying the voidage in before simulation and study of some investigators;they have a big inner loop in both the flow field which has rectangular section and entrance of the whole underside and the flow field which has cycloidal section and entrance of small center jet flow, but their loop is different because they have a reverse loop direction;Unilateral outlet of hearth top formated the excursion of the maximum of granule concentration,of granulevelocity, of turbulent kinetic energy, of turbulent dissipation rate. These results of simulation is expected to offer help and rationale for optimization and betterment of experimental facilities. |
