【作者】 张志正；

【导师】 孙保民；

【作者基本信息】 华北电力大学（北京） ， 热能工程， 2010， 博士

【摘要】 随着超(超)临界发电机组的发展,世界各国特高参数、特大容量机组越来越多,尤其是中国,发展更为迅速。超临界和超超临界机组已经成为我国电力行业“十一五规划”的主要发展机型。所以关于此类机组设备的设计制造、安全运行监测的研究越来越重要。本文为研究超(超)临界电站锅炉水冷壁的安全运行与监测,针对超(超)临界电站锅炉水冷壁截面温度场进行了大量工况的数值模拟,根据对两种结构尺寸水冷壁截面温度场的数值模拟,找到向火侧危险点温度、炉内局部热负荷、管内对流换热系数与背火侧三个特定点温度之间的关系,根据拟合的关系式发现,均与背火侧特定点温差成幂函数关系。搭建了水冷壁监测实验台进行验证和实践应用研究。根据其中一种结构尺寸的水冷壁搭建了实验装置,对拟合的关系式进行了验证和应用研究,研究发现对向火侧危险点温度和炉内局部热负荷的间接监测误差满足实践需要,对管内对流换热系数的监测由于误差放大,仅具有参考价值。提出了“背火侧三点法”监测水冷壁安全的方法,利用“背火侧三点法”监测水冷壁危险点壁温和炉内热负荷的方法在河南沁北电厂锅炉水冷壁上进行了应用,并对运行中的水冷壁和炉内燃烧工况进行了监测的实践。本文还针对沁北电厂的管子尺寸对多个厚度鳍片的水冷壁温度场进行了数值模拟,得到了鳍片危险点温度与鳍片厚度之间的关系,找到了使鳍片能满足焊接和安装要求且不超温的最小厚度,为超(超)临界压力节省较为昂贵的鳍片用钢提供了一种方法。更多还原

【Abstract】 With the development of the supercritical and ultra-supercritical units, there are more and more high-parameters, large-capacity plants in the world, which are developing much more rapidly in China. The supercritical and ultra-supercritical units have been primary choices in utility industry in the 11th five-year plan. Therefore, the design, the manufacture and the safe-operation monitoring of such units, are becoming more and more significant.The dissertation simulates a lot of the temperature field of boiler water wall in supercritical and ultra-supercritical power boilers. Based on numerical simulation to the temperature fields of the two kinds of water walls of two structural sizes, the relationship is found between the temperature on fire wall side, thermal load inside boiler, the coefficient of heat exchange and the temperature difference of three key points on back wall side. According to the fitting relationship, the formulations form a power function between those and the temperature of the special points on back wall.A monitoring water-wall test bed is built for validation and practical application. This dissertation verifies the relation and studies the application by building an experimental device according to one dimension of the water-wall structure. It finds that the error of indirect monitoring meets the practical needs for the temperature on fire wall side and thermal load inside boiler, but those only provide reference value because the errors are enlarged to monitor the coefficient of heat exchange."Three Point Method" is proposed monitoring the temperature of severe points and thermal load in this paper and is applied on the boiler in Henan Qinbei Power Plant. It plays a monitoring role on the water wall and the combustion condition in operation practice.According to numerical simulation to the temperature fields of water walls of different sizes in Qinbei Power Plant, we obtain the relation of the temperature of severe points and fin thickness, and the thinnest fin thickness which satisfies welding, installation requirements and temperature limit. This is to save a large number of steel that is more expensive to mark fin for supercritical and ultra-supercritical units.更多还原