Distributed model for heat transfer of boiler superheater system and its application

According to heat sources, the energies transferred in the superheater system were classified as six types: flue gases radiation before/behind the tube panel, flue gases radiation between the parallel tube panels, flue gases radiation inside the furnace, roof tubes radiation between the parallel tube panels, tube panel self-radiation and convection. The flue gases radiation before/behind the tube panel or inside the furnace was considered as blackbody smoke vent plane radiation. Based on the above disposal, the six types heat transfers occurred in an enclosure system, and then a distributed model for heat transfer of superheater panel was developed, which can well reflect each different factors affecting the non-uniform heat flux distribution. A simulation was made on the rear platen superheater of a 300 MW unit, which showed the heat flux distribution on the panel was non-uniform and the contribution of each type to the total heat absorbed by the superheater was quite different. The model can be used for distributed superheater thermal calculation, and can provide a base to develop a dynamic distributed parameter model of superheater system.