燃煤锅炉屏式过热器壁温耦合计算方法

A Coupled Model for Predicting the Tube Temperature of Platen Superheater of Coal-fired Boiler

锅炉受热面管壁超温严重影响电厂的安全运行。锅炉受热面管壁温度受烟气侧传热分布和管内工质吸热分布的共同影响,为此提出一种耦合传热计算模型,模型采用三维计算流体动力模型模拟炉内烟气侧的三维流动燃烧传热过程,采用一维Flownex模型模拟受热面管内的工质流动传热过程,两模型间通过壁面热流和管内工质温度的数据交互实现耦合迭代计算。该模型可同时实现炉内烟气侧三维流场和管内工质流动传热过程的数值模拟,精确体现受热面传热偏差和管间工质流量偏差对管壁温度分布的影响。该耦合传热模型应用于一台600MW超临界锅炉屏式过热器传热及壁温分布的模拟,计算结果与不同负荷下壁温测量结果吻合良好。

Overheating of boiler heating surface seriously affects the safe operation of power plant.The tube temperature of boiler heating surfaces is affected by both the gas side heat transfer and steam heat absorption.Thus,this paper presented a coupled heat transfer calculation model in which the combustion and heat transfer of gas flow was simulated by 3D CFD model;while the steam flow in the tubes was simulated by a 1D Flownex model.The two models were coupled by exchanging the data of boiler heating surface heat flux and the steam temperature in the tubes.This coupled heat transfer model integrated the simulation of gas flow in the furnace and the steam flow in the heat exchanger tubes,and thereby can accurately consider the impacts of the heat transfer and steam flow deviations on the tube temperature.This coupled heat transfer model was applied to a 600 MW supercritical boiler to predict the heat transfer and tube temperature distribution of its platen superheater.The results show that the predicted results of tube temperature at different boiler loads are in good agreement with the measurements.