E310 HEAT TRANSFER CHARACHTERISTICS OF PARTICLE CONVECTION IN FLUIDIZED-BED(Boiler-2)

The particle convection can be considered as one of dominant factors of the heat transfer mechanism in fluidized-bed. But the estimation of the effect of particle convection in the actual fluidized-bed is very difficult owing to the complicated particle movement. In this investigation, thus, heat transfer experiment under controlled particle convection was conducted by using the cylinder-shaped fluidized-bed equipped with a stirrer. The cylinder diameter was 115 mm, and the stainless foil heater was attached on the inner surface of the cylinder. The bed material was the silica sand, and average particle diameter was 0.175 mm. The static bed height was 200 mm. As the results, the heat transfer characteristics were measured under arbitrary particle velocities, and showed a strong relationship with the residence time among the heating surface. The experimental result has been well explained by using the numerical calculation with the Molerus's effective thermal conductivity with the considering of the gas convection.