Heat Transfer Coefficient at Minimum Fluidization Velocity for Gas-Solid Fluidized Beds

摘要

A semi-empirical correlation for heat transfer coefficients between dense gas-solid quiescent fluidized beds and surfaces is presented. Surface heat transfer coefficients at the minimum fluidization condition were measured using a local heat transfer probe in a 5 cm × 30 cm transparent walled, fluidized bed. The initial bed height was held constant at 17.0 cm in all cases. The powders tested were glass, sand, graphite, polypropylene and aluminum with sizes in the range from 25 μm to 1789 μm. The fluidizing medium used was air with the bed operated at atmospheric temperature and pressure. Two different distributor plates were utilized during the experiments, i.e., sintered and perforated distributor plate. Time averaged, local heat transfer coefficients acquired were averaged over repeated measurements at different times.