摘要
超/超超临界锅炉垂直水冷壁中间集箱附近的水冷壁异形鳍片区域向火侧易出现横向裂纹,可能导致水冷壁泄漏或爆管。以某660 MW超超临界锅炉为对象,介绍了水冷壁异形鳍片区域温度和热应力的数值计算模型。针对横向裂纹问题,基于计算数据分析了该区域的温度和热应力分布特征,以及锅炉负荷变化和水冷壁尺寸的影响。结果表明,异形鳍片旁的管壁向火侧顶点的轴向拉应力和等效应力大,锅炉变负荷运行易产生交变热应力,导致横向裂纹;异形鳍片中心为整个模型温度最高处,轴向应力和等效应力值也较大,需要重点关注;异形鳍片与管壁交接处等效应力大,材料失效时容易产生裂纹,可能向旁边的异形鳍片区域管壁向火侧延伸。
Transverse cracks are easily produced in ultra-supercritical boiler vertical water wall special-shaped fin region near intermediate heater.It is the hidden trouble of water wall leakage and explosion.Take special-shape fin region from a 660 MW ultra-supercritical boiler as research object.Temperature fields and thermal stress fields were obtained by numerical model.Based on calculation data,temperature and thermal stress characteristics were analyzed.The influence of varying load operation and water wall geometry size was also considered.The results show that the axial tensile stress and equivalent stress of the tube wall beside the shaped fin to the apex of the fire side are large,and the alternating load of the boiler is prone to alternating thermal stress,resulting in transverse crack.The highest temperature of the whole model is located at water wall special-shape fin center.Axial stress and equivalent stress are also large in this region.It deserves special attention.Equivalent stress is large in connection point of special-shape fin and tube wall,which results in materials failure and cracks.Cracks may extend to fireside tube of special-shape fin region.
作者
徐青蓝
周克毅
肖杰
杨浩蓝
张凌翔
XU Qinglan;ZHOU Keyi;XIAO Jie;YANG Haolan;ZHANG Lingxiang(Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education,Southeast University,Nanjing 210096,Jiangsu,China;Jiangsu Frontier Electric Technology Co.,Ltd.,Nanjing 211102,Jiangsu,China)
出处
《化工学报》
EI
CAS
CSCD
北大核心
2019年第12期4582-4589,共8页
CIESC Journal
基金
国家自然科学基金项目(51676035)
