Conductive Heat Transfer between Fluidizing Particles and a Heat Transfer Surface in a Fluidized Bed. Visualization of Temperature for Fluidizing Particles.

Heat conduction during contact between a heat transfer surface and fluidizing particles, which is one of the effective heat transfer mechanisms in a gas-solid fluidized bed, has been empirically investigated. The temperatures of the fluidizing particles during the contact period are visualized by an infrared imager. This visualization reveals that the particles have been considerably heated in the thermal boundary layer on the heat transfer surface before the contact. Based on the visualized temperature of the particles, the contact conductance between a fluidizing particle and the heat transfer surface was estimated by an inverse analysis, and using the evaluated contact conductance, the contributions of the conductive heat transfer to the total heat transfer are also evaluated.