Numerical Simulation Of Fin-Tube Heat Exchanger And Multi-Objective Optimization Design Of Structural Parameters

As a new type of renewable energy,air energy has attracted much attention in recent years.Air energy water heater is a product that uses air energy to heat water.One of the most important components is the heat exchanger.The performance of the heat exchanger is affected by a variety of structural parameters.Research on the structural parameters is very important to improve the performance of the overall air energy water heater.The research on the structural parameters of traditional heat exchangers is mostly based on experimental analysis methods.The research period is long,the experiment cost is high,and the performance of the heat exchanger is mostly evaluated by a single evaluation index,and the research results are not comprehensive.Therefore,this paper considers the use of numerical simulation method to calculate the heat exchanger,and combined with the multi-objective optimization method to optimize the design of different structural parameters of the heat exchanger.The DM module in the workbench software is used to parametrically model the four-row flat finned tube heat exchanger,and the model is meshed with ICEM software,and finally the Fluent software is used for simulation and solution.The article firstly explored the effects of different structural parameters on the performance of finned tube heat exchangers by simulation;then four parameters such as fin spacing,transverse tube spacing,longitudinal tube spacing,and the ratio of the ellipse’s long and short axis were used as optimization variables to heat transfer The performance j factor and the resistance performance f factor are the optimization goals,and the neural network model between the optimization variables and the optimization goal is established;finally,the non-dominated algorithm with elite strategy(NSGA-II)is used to carry out the established network model Search for optimization,and obtain a set of better solutions with structural parameters that meet the requirements of multiple objectives.The optimization results show that the optimal structure parameter combination obtained by taking the maximum heat transfer factor j and the minimum resistance f factor of the finned tube heat exchanger as the optimization objective is: fin spacing Fp=1.5mm,transverse tube spacing St=30.618 mm,Longitudinal pipe spacing Sl=28mm and ellipse major axis a=5.90 mm,minor axis b=3.62 mm.A simulation model was established for the optimized structural parameters and solved by Fluent software.It was found that the heat transfer j factor of the finned tube heat exchanger was increased by 4.20% compared with before optimization,and the resistance f factor was reduced by 77.38% compared with before optimization.This shows that although the optimized fin-tube heat exchanger has little increase in heat transfer performance,it greatly reduces the resistance performance.The research methods and results obtained in this paper provide a certain reference value for the optimization of the structural parameters of the fin-tube heat exchanger.