| Flue-gas desulfurization technology with circulating fluidized bed(CFB) has been developed in the world recently. In order to provide the basis on optimal structure of inlet for those who would go in for research on process of mass and heat transfer of gas-solid in CFB, the effects of inlet structure on distribution characteristics of velocity field in riser were studied and numerical simulations were performed in the paper.The inlet structure of venturi-pipe that was extensively utilized in industry was adopted. Distribution of axial velocity across radial position in riser was obtained through experiment. The characteristics of axial velocity distribution were thoroughly discussed with uneven conception. The reasons that the flow phenomena appeared in riser were extensively analyzed. The results showed that the even of velocity profiles in the bottom of riser was badly affected by side inlet duck and circulating feed inlet. As a result, the bad flow behavior in the bottom of riser arised and what is more, in the venturi diffusive section, the eddy, with which the region of steady-flow in riser changed, appeared on the side of circulator.Through comparison of the results of numerical simulation and experiment results, two equation model was validated with constants recommended by Launder and Spalding in the paper. Two different types of inlet structure were designed and numerical simulation of these bodies was made with the help of model. The better inlet type was put forward based on the experiment and numerical simulation.
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