Thermodynamic Design And Optimization Systems Of Finned Tube Heat Exchangers

Finned-and-tube heat exchangers have been widely employed in many engineering fields like as refrigerating,air conditioning,ventilation.In the present study,the modified particle swarm optimization and genetic algorithm are adopted as the mothods of optimization design of heat exchangers.According to specific design requirements,the weight,volume or pressure drop may be chosen as the optimization single-objective function and the weight,volume and pressure drop are followed by weight factor could be chosen as the optimization multi-objective function.To meet heat exchange requirements and allowable pressure drop are considered as restrictive conditions.The length of tube bundles,the numbers of tube rows,the width of heat exchanger core and fin pitch are taken as the optimization variables.The main foundings are as follows.For optimization design of heat exchangers and softwares and projects in design and optmization of heat exchangers,literature from both in China and abroad is carefully examined.A simple introduction to the genetic algorithm and particle swarm optimization is provided.The traditional genetic algorithm and particle swarm optimization is modified and detailed flow chart is also provided.The resluts are compared with results in literature and show good agreement.As for constrained optimization problem the measures are taken that the variables which unsatisfied constrained conditions are discarded directly,instead seeking variables which could satisfy the constrained conditions again,to ensure that each set of variable combinations are possible solutions,so as to speed up the pace for convergence.The optimization model of a finned-and-tube heat exchanger is built.The geometry paremeters are obtained.Heat transfer and fliud flow characteristics are added to the optmization model.The particle swarm optimization and genetic algorithm are used in the optimization design process instead of debuging parameters.Design case and optimzation case are conducted based on the minimum volume,minimum weight and minimum pressure drop.Based on the single-objective optimization,a multi-objective optimization is also conducted.The results show the particle swarm optimization has stronger global searching ability and faster calculation speed,which could be widely employed in optimization of heat exchangers.Based on above discussion,Finned tube heat exchanger design and optimization software is successfully developed,which improves efficiency of design and optimization of finned tube heat exchanger.