导光管直径和长度对传热影响的模拟分析

Simulation analysis of effect of diameter and length of light pipes on heat transfer

导光管可以改善室内光环境,但在高大空间建筑中安装大量导光管会导致夏季室内热量增加、冬季室内热量损失,因此必须考虑传热问题。通过改变导光管的直径和长度,对北京地区夏季和冬季工况下高大空间建筑导光管的传热特性进行了模拟分析。结果表明,夏季时,导光管内部空气分布较为均匀,平均温度在20℃至32℃之间变化,随着导光管直径增加,管内空气平均温度先下降后趋于平稳,总热损失逐渐增大;随着导光管长度增加,平均温度呈下降趋势,总传热量无明显变化趋势,最终保持不变。冬季时,导光管内部空气分为两个区域,平均温度在0℃至25℃之间变化,随着导光管直径增加,平均温度升高,总传热量增大;随着导光管长度增加,平均温度先上升后趋于平缓,总传热量先增加,最终变化不明显。

Light pipes can improve indoor luminous environment and are increasingly used in large space buildings.The use of light pipes leads to heat gain in summer and heat loss in winter,heat transfer must be considered in buildings with a large number of light pipes installed.In this paper,CFD simulation was used to analyze the heat transfer characteristics of light pipes in Beijing under summer and winter conditions.The results showed that,in summer,the air inside the tube is more evenly distributed,and the average temperature varies between 20℃and 32℃.As the diameter of the light pipe increased,the average temperature of the air inside the tube first decreased and then tended to be stable,and the total heat loss gradually increased.As the length of the light pipe increased,the average temperature showed a decreasing trend,and the total heat transfer did not have a significant trend,but finally remained unchanged.In winter,the air inside the tube is divided into two zones and the average temperature varies between 0℃and 25℃.As the diameter of the light pipe increased,the average temperature rose and the total heat transfer increased;as the length of the light pipe increased,the average temperature first rose and then tended to be smooth,and the total heat transfer first increased and then remained unchanged.