换热表面结垢对U型管蒸汽发生器传热性能的影响分析

U型管蒸汽发生器的壳侧沉积了来自二回路系统中的腐蚀产物，结垢导致热量聚积在金属换热管上，容易造成垢下热点腐蚀，危害设备安全。为了明确结垢对蒸汽发生器传热性能的影响，本研究基于仿真平台APROS建立了U型管蒸汽发生器的分布式模型，并根据已公开论文中的数据进行了模型准确性验证；推导了污垢热阻与表面换热系数之间的关系式，分析了不同结垢厚度、位置对U型管蒸汽发生器换热区域的传热管壁面温度、流体温度、传热系数、热流密度等的影响程度。研究结果表明：随着结垢程度的加剧，蒸汽发生器的换热效率不断降低，出口蒸汽品质不断下降；结垢对沸腾段换热效率的影响比对过冷段换热效率的影响更大。

Analysis of the Influence of Heat Exchange Surface Fouling on Heat Transfer Performance of U tube Steam Generator

Corrosion products from the secondary loop system were deposited on the shell side of the U tube steam generator. Fouling led to heat accumulation on the metal heat exchange tubes, which is easy to cause hot spot corrosion under fouling and harm the safety of equipment. In order to clarify the influence of fouling on the heat transfer performance of steam generators, this study established a distributed model for the U tube steam generator based on simulation platform APROS, and verified the model accuracy according to the data in published papers; the relationship between fouling thermal resistance and surface heat transfer coefficient was derived, and the influence of different fouling thickness and positions on the tube wall temperature, fluid temperature, heat transfer coefficient and heat flux in the heat exchange area of the U tube steam generator was analyzed. The results show that the heat transfer efficiency of the steam generator decreases and the outlet steam quality decreases with the increase of fouling thickness; the effect of fouling on the heat transfer efficiency of boiling section is greater than that of subcooling section.