Bed to wall heat transfer in supercritical water fluidized bed

The Eulerian two-fluid model based on Kinetic Theory of Granular Flow in a fluidized bed was established in this paper, and the physical model of movement of single bubble along the wall is adopted. The comparison studies of particle distribution, temperature distribution and transient heat transfer characteristics between supercritical water (SCW) fluidized bed and gas-solid fluidized bed were carried out. The results show that the bubble diameter and rise velocity in SCW fluidized bed is smaller than those in gas-solid fluidized bed. The bed-wall heat transfer coefficient is negative related to solid volume fraction in SCW fluidized bed, while positive in gas-solid fluidized bed. What is more, the bed-wall heat transfer coefficient is sensitive to superficial velocity where the solid volume fraction is low, which is different from gas-solid fluidized bed.