循环流化床锅炉炉内传热的影响因素  

Factors affecting the heat transfer in a circulating fluidized bed boiler

作　　者：李金晶[1] 李燕[1] 吕俊复[1] 岳光溪[1] 

机构地区：[1]清华大学热能工程系热科学与动力工程教育部重点实验室,北京100084

出　　处：《清华大学学报（自然科学版）》2007年第11期2026-2030,共5页Journal of Tsinghua University(Science and Technology)

基　　金：国家"九七三"重点基础研究项目(G1999022204)

摘　　要：为定量分析受热面布置、床内流动、管内流动和床温等对循环流化床内传热和炉内辐射换热份额的影响，利用已有循环流化床炉内传热计算模型，比较了工程中常见工况下传热系数与设定标准工况下传热系数的偏差。结果显示：局部物料浓度是影响传热系数的最重要因素，相对偏差可达50％；流化风速、床温、工质温度或受热面金属导热系数影响下的传热系数相对偏差在5%～50％内变化；而烟气辐射厚度、管节距和管径的影响相对较小，传热系数相对偏差在5％以下；工质侧换热系数大于3kW·m^-2·K^-1时，对传热系数的影响较小。工程上传热系数的辐射贡献通常约为60％。The relative variations of the heat transfer coefficients for various Operating conditions were calculated for a circulating fluldized bed （CFB） boiler to quantitatively analyze the effects of the geometry and physical properties of the heated surface, the hydrodynamics in the bed and inside the tube, and the bed temperature on the heat transfer in the CFB boiler furnace and the radiation heat transfer. The results show that the local solid suspension concentration most strongly influences the heat transfer coefficients, with relative deviations more than 50%. The relative deviations of the beat transfer coefficients range from 5% to 50% for various bed gas velocities, bed temperatures, water or steam temperatures inside the tube, and thermal conductivity of the heated surface. The relative deviations are less than 5 % for various flue gas radiation thicknesses, tube pitches, and tube diameters, which can he neglected. The effect of the convective heat transfer inside the tube on the heat transfer in the CFB boiler furnace is important if the convective heat transfer coefficient is less than 3 kW·m^-2·K^-1. The results also show that radiation contributes 60% of the total heat transfer in a practical CFB boiler.

关 键 词：循环流化床 炉内传热 数值计算 辐射传热 

分 类 号：TK124[动力工程及工程热物理—工程热物理]