关键词: NEN型立式换热器, 计算载荷, 有限元模型, 塑性极限载荷法, 子模型

Abstract: Currently large NEN vertical heat exchangers are widely used in process units. This paper expounds several calculation points based on the development of the calculation of such heat exchangers. Firstly, loads that are easily ignored in heat exchanger standards such as weight load and pressure drop should be considered; secondly, several Ansys finite element models dealing with such devices are summarized, including solid models, multi-point constraint (MPC) method models, and simplified models such as tube plates simplified to equivalent solid plates; finally, the application of various models are discussed. Based on the conservative analysis and evaluation of the connection between the shell and the tube plate in the current JB/T 4732 standard, the plastic limit load method is recommended in addition to the simplified elastic-plastic method and the primary structure method in ASME, and sub-model structure can be combined with the analysis to improve efficiency. Finally, the calculation results are summarized with one NEN reactor as an example.

Key words: NEN vertical heat exchanger, specified load, finite element modeling, plastic limit load method, submodel