This research addresses the design, development and calibration of diagnostic tools for high temperature fluidized beds. An abrasion- resistant heat flux transducer will be used to measure the local heat flux between a high temperature fluidized bed and an immersed surface. An optical probe will be developed to detect the local presence of bubbles in high temperature beds. The optical probe will be used to measure the bubble size distribution, bubble rise speed, and volumetric bubble fraction. After the devices have been developed and calibrated, they will be used to understand the heat transfer in high temperature fluidized beds under a variety of operating conditions. Considerable attention has been devoted to the development of fluidized bed combustion processes for high sulfur coal and other solid fuels since the sulfur emissions from this technology can easily meet the air quality standards. Fluidized bed combustors also have the advantage of flexibility in regard to fuel type because they can be designed to burn several different types of fuels. Most of the previous studies of instantaneous local bed-to-surface heat transfer measurements are restricted to near room temperature conditions. The advancement of our understanding of fluidized beds requires the experimental characterization of the high temperature phenomena. This project will provide the experimental devices and data to meet this overall objective.
