基于Ansys Workbench的换热管断裂行为模拟分析

某石化企业焦油蒸馏装置的配套换热器在运行了3年之后,换热器内多根换热管发生了泄露和断裂。为了查明换热器换热管的失效原因,利用Ansys Workbench 13.0软件建立了流固耦合模型,通过流固耦合模拟获得了换热管束的真实应力状态。结果表明:热酚油进口附近的换热管承受了比较高的拉应力;同时研究了换热管内外流体对换热管的腐蚀作用,确定了冷却水中的氯离子和热焦油中的硫元素是造成换热管腐蚀的主要杂质。最终,根据换热管断口形态,确定了应力腐蚀开裂(SCC)是导致换热管失效的主要原因。

Failure Analysis of Heat Exchange Tubes Based on Ansys Workbench

A number of tube leaks and fractures occurred on a heat exchanger used in a tar distillation unit after operation of only three years. In order to identify the cause of this failure, a fluid-structure interaction simulation using Ansys Workbench 13.0 was performed to calculate its state of real stress distribution. The result revealed that the tubes which were close to the hot oil inlet suffered from high tensile stress. At the same time, chlorine and sulfur element which were in the cold water and hot oil respectively had corrosive effects to the tubes. Finally, the morphological feature of fracture was studied. It was found that tube failure was mainly caused by stress corrosion cracking (SCC).