Heat transfer between an isolated bubble and the dense phase in a fluidized bed

Heat transfer between the bubble and dense phases of a bubbling fluidized b ed plays a very important role in the system performance, especially for ap plications involving solids drying and gas-phase combustion. However, very few experimental data are available on this subject in the literature. An e xperimental and modelling investigation on the heat transfer behaviour of i solated bubbles injected into an incipiently fluidized bed is reported in t his paper. A new single-thermocouple technique was developed to measure the heat transfer coefficient. The effects of bed particle type and size, and bubble size on the heat transfer coefficient were examined. The heat transf er coefficient was found to exhibit a maximum as the bubble size increased in the bubble size range investigated. The bed particle size had a comparat ively small effect on the heat transfer coefficient. A simple mathematical model was developed which provides good agreement with experimental data.