燃煤电厂锅炉辐射受热面温度及热应力分析

Numerical Analysis of the Temperature and Thermal Stress of Membrane Waterwall of Coal-fired Power Plant

建立了超临界锅炉膜式水冷壁有限元数学模型,结合炉膛分区热力计算的相关理论,求得管内对流换热系数和管外炉侧平均热流密度。应用ANSYS WORKBENCH软件,模拟得出各区段水冷壁截面温度及热应力分布。结果表明:各区段温度及热应力的分布规律基本相同,最高温度集中在鳍片向火侧的顶点附近;最大热应力集中在管内向火侧的壁面附近;针对区段4研究了管壁厚度变化、鳍片厚度变化、鳍片长度变化,得出结论:温度和热应力具有同等的变化属性,随着管壁厚度和鳍片长度的变化呈正比变化趋势;随着鳍片厚度的变化呈反比趋势。

A finite element analysis model was established in the paper. The outlet temperature of working medium,the heat transfer coefficient in the tube and the heat-flux density of the fire-facing side are calculated by using the theory of furnace zoned thermal calculation.The distributions of temperature and thermal stress of diffenent zone are determined by numerical method of ANSYS WORKBENCH.The results show that the distributions of temperature and thermal stress of diffenent zone have the similar rules.The highest temperature occurs at the facing flame fin＇s end and the maximum thermal stress occurs at the facing flame inner of water-wall tube.The study of zone four by changing the thickness of tube and fins,the length of fins draw the conclusion that the change rules of the temperature and thermal stress had the similar change trend.it was proportional to the change of the thickness of tube and the length of fins,and inversed proportion to the thinkness of the fins.