Modeling of Radiative Heat Transfer in the Freeboard of a Fluidized Bed Combustor Using the Zone Method of Analysis


Abstract: Radiative heat transfer in the freeboard of the METU 0.3 MW_{t} atmospheric bubbling fluidized bed combustor (ABFBC) test rig was analyzed by applying one of the most accurate radiation models, the zone method of analysis, to the prediction of incident radiative heat fluxes on the side walls. The accuracy of the method was tested by comparing its predictions with measured incident radiative fluxes on the walls. The freeboard was treated as a 3-D rectangular enclosure containing gray, absorbing, emitting and isotropically scattering medium. Data for application and validation were generated from METU 0.3 MW_{t} ABFBC burning lignite in its own ash. Comparisons revealed that the zone method of analysis reproduces the wall fluxes in the freeboard of fluidized bed combustors containing particle-laden combustion gases reasonably well. The sensitivity of predicted heat fluxes to the presence of particles was also examined and found to be insensitive at low particle loads typical of bubbling fluidized bed combustors.

Keywords: Zone method of analysis, Radiative heat transfer in freeboard, Fluidized bed coal combustion

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