电站锅炉过热系统分布式传热模型及其应用

根据热量来源将过热系统传递的能量分为屏前/屏后烟气辐射、屏间烟气辐射、炉膛火焰辐射、炉顶管辐射、管屏表面自身辐射以及对流传热6种类型。将屏前/屏后烟气辐射以及炉膛火焰辐射视为烟黑体窗平面的辐射，在此基础上把6种类型的传热归结到一个封闭系统内，进而建立了一种可同时反映各种不均匀性因素的过热系统分布式传热模型。应用模型对某台300MW机组后屏过热器热流分布进行模拟，揭示了各种类型热流的不均匀性和对总传热量贡献的差别。该模型可以用于过热系统的分布式热力计算，并可为过热系统分布参数动态模型的建立提供必要的边界条件。

A 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/bebind 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 300MW 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.