基于流固耦合理论的螺旋折流板换热器结构优化研究

Structural Optimization of Shell-Tube Heat Exchanger with Helical Baffles Based on Fluid-Structure Interaction

针对螺旋折流板换热器热-结构综合性能,以螺旋角和搭接度为优化变量,基于流固耦合理论,采用二阶多项式响应面模型和遗传算法对螺旋折流板换热器进行了结构优化研究。结果表明:当壳侧入口流量为1.5 m×s^(-1)时,对于流动传热性能,单位压降传热系数随螺旋角的增大呈现先增大后减小的趋势,随搭接度的增大而减小,且受螺旋角的影响更大;对于折流板机械强度性能,最大剪应力的最大值随着螺旋角的增大而增大,而基本不受搭接度的影响。多目标优化以单位压降传热系数最大化,最大剪应力的最大值在许用应力范围内且最小化为目标函数,得到了三种优化结构。对比优化前后,单位压降传热系数平均提升了14.1%,最大剪应力的最大值平均降低了4.1%。研究结果为螺旋折流板换热器的工业化设计提供了理论指导。

Helical angle and baffle overlap proportion as two variables were used in structural optimization of shell-tube heat exchanger with helical baffles,and a second polynomial regression response surface method combined with genetic algorithm was applied. The study was based on fluid-structure interaction theory considering thermal structural performance. The results show that the heat transfer coefficient per pressure drop increases first and then decreases with the increase of helical angle, and it decreases with the increase of baffle overlap proportion when flow velocity ν = 1.5 m×s^-1. Helical angle is more sensitive than baffle overlap proportion for flow and heat transfer. The maximum shear stress increases with the increase of helical angle, but it is almost unaffected by baffle overlap proportion. The optimization objectives are maximization of heat transfer coefficient per pressure drop and minimization of maximum shear stress within allowable stress ranges, and three optimal structures are obtained. The optimal results show that the heat exchanger coefficient per pressure drop is increased by 14.1% on average and the maximum shear stress is reduced by 4.1% on average. These results provide theoretical guidance for industrial design of shell-tube heat exchanger with helical baffles.