基于LBM的泡沫金属与翅片相变储能系统性能对比分析

Performance comparison of metal foam and fin phase-change energy storage system based on LBM

为了研究翅片和泡沫金属铜对相变储能系统性能的影响,使用四参数随机生长法(QSGS)构建了孔隙密度(PPI)分别为20PPI、30PPI的泡沫铜复合相变材料模型,并构建了等铜质量的翅片相变材料模型。在此基础上,采用格子玻尔兹曼(LBM)数值模拟方法对相变材料(PCM)的储/放热过程进行了数值模拟,基于努塞尔数、液相率、PCM流动速度、PCM熔化/凝固时间对比分析了添加翅片以及添加泡沫金属结构对相变材料换热性能的影响。结果表明,在储热过程中,由于泡沫金属的存在会抑制熔化过程中对流换热的发展,双翅片结构的努塞尔数高于泡沫金属结构,熔化时间更短,相比于20PPI、30PPI泡沫铜复合相变材料分别缩短了28.55%、17.5%;在放热过程中,泡沫金属的存在会增加热传导面积,泡沫金属结构的凝固速度高于翅片结构,30PPI泡沫金属结构的凝固时间相比于翅片、20PPI泡沫铜复合相变材料分别缩短了65.80%、20.24%。综合考虑储放热两个过程,30PPI泡沫金属结构的总储放热时间最短,相比于翅片、20PPI泡沫铜复合相变材料分别缩短了27.81%、15.32%。在耗费相同金属材料的条件下,采用泡沫结构是更为有效的提升储能效率的手段。

To investigate the influence of fins and copper metal foam on the performance of phase-change energy storage systems,composite phase-change material(PCM)models with 20 and 30 pore per inch(PPI)were constructed using the quartet structure generation set.Additionally,a finned PCM model with an equal copper mass was constructed.Subsequently,numerical simulation based on the lattice Boltzmann method was employed to simulate the heat storage/release process of PCM.The effects of adding fins and foam metal structures on the heat transfer performance of PCM were compared and analyzed based on Nusselt number,liquid fraction,PCM flow rate,and PCM melting/solidification time.The results showed that the presence of foam metal during the heat storage process hindered the development of convective heat transfer during the melting process.The Nusselt number of the double fin structure was higher than that of the foam metal structure,resulting in a shorter melting time for double fin structure.Compared to the 20 PPI and 30 PPI foam copper composite PCMs,the melting time was reduced by 28.55%and 17.5%,respectively.During the heat release process,the presence of foam metal increased the heat conduction area.The solidification speed of the foam metal structure was higher than that of the fin structure,and the solidification time of the 30 PPI foam metal structure was reduced by 65.80%and 20.24%compared to the fin and 20 PPI foam copper composite PCMs,respectively.Considering the heat storage and release processes,the total heat storage/release time of the 30 PPI foam metal structure was the shortest,with reductions of 27.81%and 15.32%compared to the fin and 20 PPI foam copper composite PCMs,respectively.Under the condition of consuming the same amount of metal material,adopting the foam structure is a more effective means to improve energy storage efficiency.