Intelligent Optimization Design Of Structure For Wide-channel Plate Heat Exchanger

Responding to the national call,all industries should do a good job in energy conservation and emission reduction.Heat exchanger is an extremely important energy conversion equipment in practical project application.At present,it has been widely used in various engineering fields,such as petroleum,machinery,energy,electricity,refrigeration,transportation and so on.Plate heat exchanger is a common type of heat exchanger,which has the advantages of compact structure,compact size,high economic value and high performance.Usually divided into wide-channel plate heat exchanger and removable plate heat exchanger these two different structures.Compared with the detachable structure,the wide-channel type improves the service temperature and compression capacity of the plate heat exchanger,so it has a wider range of application scenarios in industrial production.However,although the wide channel plate heat exchanger can enhance the heat transfer effect,but in order to improve the heat transfer effect and resistance characteristics,it is necessary to optimize the structure size of the wide-channel plate heat exchanger and the internal flow characteristics.At present,the structure optimization design method of plate heat exchanger is mainly through three-dimensional modeling,and then the finite element simulation software is used for numerical simulation analysis.A large number of simulation experiments are carried out on the structure of plate heat exchanger.Such structural design optimization method is particularly time-consuming,and a lot of manpower and material resources are wasted.Therefore,this paper proposes to use surrogate model instead of the actual finite element model of wide-channel plate heat exchanger,and uses multi-objective intelligent optimization to solve the design scheme.The main use is the multi-objective particle swarm optimization and the multi-objective brain storm optimization.It provides a scientific basis for the design of wide-channel plate heat exchanger in actual production and application scenarios,and ensures the practicability,accuracy and high efficiency of the proposed design scheme.The main work completed in this paper is as follows:(1)Aiming at the structural design of wide-channel heat exchange plates,a multiobjective intelligent optimization design method based on surrogate model is proposed.Heat exchange plate is its core component.In order to improve the heat exchange effect of wide-channel plate heat exchanger and reduce energy loss,it is necessary to optimize the shape design of heat exchange plate.The structure parameters of single-layer heat exchange plates were extracted,and the typical heat exchange plates with different structures and operating conditions were generated by orthogonal method.Based on the Fluent numerical simulation software,the corresponding heat transfer effect and energy loss of the heat exchange plate were obtained,and the comprehensive criterion relationship model of the two was obtained by fitting.Taking maximum heat transfer effect and minimum energy loss as optimization objectives,multi-objective particle swarm optimization and multi-objective brain storm optimization were used to find the optimal structural parameters of the heat transfer plate.The results show that the structure parameters which have great influence on the performance can be found by using the orthogonal experimental design method.By adopting the multi-objective intelligent optimization,the shape parameter distribution range of the heat exchange plate with the best heat transfer effect and the least energy loss can be found.(2)In view of the uncertainties of the density and flow rate of the flowing heat transfer medium in the wide-channel plate heat exchanger in practical application scenarios,an intelligent optimization design method for the structure of the widechannel plate heat exchanger based on interval constraints is proposed.It is usually difficult to obtain the probability distribution range of uncertain factors,but it is often easy to obtain the variation range.Therefore,interval number is used in this paper to describe the uncertain factors,which is an effective way to realize the performance optimization design of wide channel plate heat exchanger.The interval constraint method is used to limit the range of the uncertainty factors of the heat exchange medium under the actual application conditions,and the triangle fuzzy number is used to reflect the degree of constraint violation,and the heat exchange performance and pressure loss surrogate model are obtained through neural network training.Finally,the multiobjective particle swarm optimization and the multi-objective brain storm optimization are used to find the optimal structural variables of the wide-channel plate heat exchanger under uncertain conditions.The results show that the multi-objective intelligent optimization can quickly and accurately obtain heat exchanger structural variables with better heat transfer effects and lower cost,which provides convenience for the design of high-efficiency and low-cost wide-channel plate heat exchangers.The thesis includes 23 figures,20 tables and 106 references.