Fluidization and Surface-to-bed Heat Transfer in a Sound Assisted Bubbling Fluidized Bed of Fine Powders

摘要

Most of the research work in heat transfer in bubbling fluidized beds is focused on Geldart B and D particles. Very little information is available on heat transfer to fine powders (Geldart Group C and Group A). In this paper, heat transfer between a bubbling fluidized bed of fine powders and immersed heating surface in absence and presence of acoustic waves is investigated. The average heat transfer coefficients, surface temperatures, local heat transfer coefficients were measured at various fluidization velocities at different positions on heat transfer tube and with different materials. Acoustic energy of sufficient intensity and sound pressure level improves the quality of fluidization. Heat transfer rates can be improved by oscillating the flow at certain frequencies. The data is presented as a function of excess air velocity and sound pressure level, average and local heat transfer coefficients.