树形管道与金属通道在石蜡相变蓄热优化中的应用

Application of tree-shaped tubes and metal channels to latent heat storage enhancement of paraffin

为优化石蜡的蓄/放热速率等相变换热性能,设计具有多尺度结构的树形换热管,在降低流动阻力的同时提高石蜡内部温度的均匀性,通过实验研究树形换热管的入口水温和体积流量对石蜡蓄热性能的影响。通过在石蜡中埋置铜管/柱和不锈钢管/柱等高导热的金属通道,进一步增大有效传热,提高石蜡的蓄热性能。研究结果表明:石蜡的蓄热有效度与树形换热管的入口水温和体积流量成正相关,温度分布均匀度随傅里叶数的增加而逐渐降低并趋于平稳;在纯石蜡中埋置金属通道能有效改善石蜡的蓄热性能,在实验中埋置直径为16 mm的实心铜柱效果最明显,可使石蜡的蓄热有效度比纯石蜡提高23.0%,且内部温度分布也比纯石蜡更均匀。

Multi-scale tree-shaped tubes were designed to enhance the heat charging/discharging rates of paraffin and improve temperature uniformity inside paraffin at reduced flow pressure drop. Experiments were conducted to investigate the influence of the inlet temperatures and volume flow rates of the hot fluid on the thermal storage performance of paraffin. Metal channels such as copper pipes/cylinders and steel pipes/cylinders were embedded in paraffin to enhance the efficiency of heat transfer and then increased the thermal storage performance of paraffin. The results show that the thermal storage effectiveness of paraffin increase with the increase of the inlet temperature and volume flow rate of hot water, and the temperature profile in paraffin becomes uneven and then remains steady. Compared to the pure paraffin, the effect of metal channels on the thermal storage performance of paraffin is significant. The thermal storage effectiveness increases by 23.0% when copper cylinders with a diameter of 16 mm are embedded. Moreover, the temperature distribution inside paraffin with metal channels is more uniform than that of the pure paraffin.