基于热流耦合的换热器结垢对传热性能的影响分析

Analysis of the Influence of Heat Exchanger Fouling on Heat Transfer Performance Based on Thermal Fluid Coupling

选取工程中常用的管壳式换热器为研究对象,针对换热器中的结垢问题进行数值模拟和传热性能分析。换热器管程介质为常温循环水,壳程为高温减顶气。使用SolidWorks对换热器固体域和流体域进行建模,利用Fluent在相同工况条件下分别对换热器在管内结垢、管外结垢和壳内结垢等情形进行数值模拟,得到了换热器内的速度场、温度场和压力场分布,由此分析管壳式换热器的传热性能,并获得了污垢位置和厚度对换热器传热性能的影响规律。结果表明:随着污垢厚度的增加,换热器的传热系数逐渐减小,结垢侧压降逐渐升高;换热管内侧结垢对换热器传热性能的影响最大,壳程内侧影响最小。

A commonly used shell-tube heat exchanger in engineering was selected as the research object.Heat transfer perfor⁃mance was analyzed by numerical simulation for the fouling in the heat exchanger.The mediums in the tube and shell of the heat exchanger were circulating water and vacuum overhead gas respectively.The domains for solid and fluid of the heat exchanger were modeled by SolidWorks.The numerical simulation of the heat exchanger was carried out in Fluent under three different foul⁃ing conditions,namely fouling in the tube,fouling outside the tube and fouling inside the shell.The flow field,temperature and pressure distributions in the heat exchanger were obtained.Furthermore,the heat transfer performance of shell-tube heat exchang⁃er was analyzed,and the effect law of fouling position and thickness on heat transfer performance of heat exchanger was obtained.It is found that with the increase of the fouling thickness,the heat transfer coefficient of the heat exchanger decreases,and the pressure drop increases;the fouling inside the tube has more impact on the heat transfer performance of the heat exchanger,and the fouling inside the shell has less impact.