不同倾角下通孔金属泡沫强化蓄热实验研究

Experimental Investigation on the Heat Storage Enhancement of Phase Change Materials Embedded in Open-Cell Metal Foam in an Inclined Rectangular Enclosure

为了研究不同倾角下纯石蜡及通孔金属泡沫内嵌石蜡熔化过程的特性规律,搭建了固液相变可视化实验系统,利用该系统对蓄热过程中相界面的迁移进行了观察及记录,以探索不同倾角下自然对流对石蜡相变蓄热过程影响的作用机制。实验结果表明:在相变换热装置倾角不为零(θ≠0°)状态下固液相界面由于液体区域内自然对流的影响而呈现倾斜状态;在水平(θ=0°)状态下固液相界面宏观上基本水平,纯石蜡水平熔化时微观呈现锯齿状相界面;不同倾角对纯石蜡熔化过程具有很大影响,随着θ逐渐减小,相变材料完全熔化时间越来越短,水平时纯石蜡熔化时间比30°、60°及90°倾角时分别减少14.77%、25%和34.16%。倾角对石蜡内嵌金属泡沫蓄热过程的影响可以忽略不计。

To study the melting behaviors of pure paraffin and the paraffin embedded in open-cell metal foam under different inclination angles between the metal foam enclosure and ground,an experimental system enabling visualization of solid-liquid interface was built.The system was used to observe and record the evolution of phase change interface in the melting process to justify the contribution of natural convection under different inclination angles to the migration of melting front.Results demonstrated that the solid-liquid interface was found to be tilted in the inclined(θ≠0°) position.At the horizontal state (θ=0°),the interface for pure paraffin was overall horizontal but locally serrated.Different inclination angles were found to have great influence on the melting process of pure paraffin.The full melting time was reduced with the decrease of inclination angel θ.The full melting time of pure paraffin in horizontal position was decreased by 14.77%,25% and 34.16% in comparison with 30-degree,60-degree and 90-degree cases,respectively.This indicates that the contribution of inclination angle to the thermal storage process of paraffin embedded in metal foam can be neglected.