Structural Optimization Of Wave-tape Inserted Into Heat Transfer Tube Based On Multi-island Genetic Algorithm

Improving the performance of shell-and-tube heat exchangers is one of the ways to achieve the purposes of improving energy efficiency,energy saving and emission reduction.In this paper,a wave-tape insert configuration for pipe is discussed.In the Reynolds number range from 400 to 1200,the characteristics of heat transfer,flow resistance and overall performance of this configuration is studied by using numerical simulation.We find that this structure can generally enhance the overall performance of heat exchanger tubes,but the increase slows down with the increase of Reynolds number.In addition,the values of the Nu/Nu₀ and f/f₀ will also increase with the increase of Reynolds number,but the increase rate varies with the change of Reynolds number.The number,location,influence range of the longitudinal turbulence induced by the wave-tape structure are the key factors affecting the overall performance.The amplitude and width of the wave-tape are two key factors affecting the overall performance.The optimization of traditional wave-tape is carried out under different Reynolds number and width of the wave-tape conditions by multi-island genetic algorithm.Under two Reynolds number conditions,the optimal structure is similar to the sinusoidal one,but the maximum height and the average height of the three optimization parameters increase,which indicates that the structure needs a certain height to ensure the effect of disturbance.The value of PEC under the high Reynolds number condition increased greatly to 30.27%,and the value increases to 3.43,the optimization effect is more obvious when comparing with the low Reynolds number condition.The results of optimization under two widths are similar to that of sinusoidal structure,with both the maximum height and the average height increasing.The value of PEC of the small width structure increased more,reaching 20.61%,and the optimization effect was more obvious.However,the value of PEC with large width is larger,so its overall performance is better.The increase of width will lead to the increase of value of PEC,but with the increase of width,the increasing speed will reduce.