设计了一套定量测试不同工况下壳管式相变蓄热器传热效率装置。采用壳管式相变储热,石蜡填充入壳管间,管内通入冷、热载流体,模拟吸热放热过程。测试发现:相同入口条件下,单位时间传热量随入口水温增加呈线性增加;管内载流体流量加大有助于提高传热水平,15~60 L/h流量内单位时间传热量增速随流量增加放缓;不同材质传热管单位时间传热量变化并不明显,表明管道热阻在相变蓄热器总热阻中所占份额较小;相同工况下的蓄热过程,热载流体由下向上流动传热形式明显优于由上向下管排形式;尝试在封装相变材料中添加金属网状结构,强化相变材料内部热传导速率,对比发现相同工况下相变材料中添加金属网状结构,可提高10%~15%左右传热量。
A set of quantitative to test heat transfer efficiency of shell and tube heat exchanger under different conditions is designed.The research use shell and tube as heat storage device,with paraffin filled into the space between shell and tube,cold/hot carrier fluid in the tube,which simulates the process of endothermic and exothermic.The results indicate that the heat exchange value increased linearly with inlet water temperature increasing under the same conditions.The increasing fluid flow improves the level of heat transfer,heat exchange growth slowing down with flow increasing in 15-60L/h area.Compared different materials for heat pipe,heat exchange in unit time dose not change significantly,which shows that the thermal resistance of pipe was smaller in whole resistance.The heat transfer in the form of bottom-top is better than the form of top-bottom tube row in the process of endothermic.The metal mesh structure is added into phase change materials to strengthen the internal rate of heat conduction,which can increase 10%-15% heat transfer by comparing.Key wrods: phase change thermal storage;heat transfer enhancement;thermal resistance;shell and tube heat exchanger