具有表面辐射的建筑室内自然对流换热的研究

Interior Natural Convection and Heat Transfer with Thermal Radiation in a Building

随着人们生活水平以及节能意识的提高,对建筑热工性能评价和建筑节能越来越重视。将建筑房间简化为含有多孔介质的双区域模型,因此,此类模型被应用到更多的领域。通过数值模拟展现了实际建筑环境中各物理条件对室内通风与热环境的影响,为室内舒适度的建设提供了依据。基于有限元法对含有多孔介质复合腔体这一类双区域模型的壁面热辐射与自然对流耦合换热问题在建筑房间内的应用进行了数值模拟分析。模拟了不同工况下多孔介质复合腔体内的流场和温度场随时间的变化情况。结果表明,表面热辐射对建筑房间内的自然对流换热有明显的增强作用;冬季与夏季,中间层与顶层不同的边界条件影响着室内的对流换热即方腔热环境的改变;多孔介质厚度d较大时能减弱传热,当到达一定值时影响不明显。

With the development of living standards and energy conservation awareness, people pay more and more attention to the building energy saving and evaluation of building thermal performance. The building room is simplified as a cavity model partially filled with a parous medium, therefore, this kind of model is applied in more fields. The results in this paper provide useful information for the ventilation and thermal environments, and indoor comfort. The effect of surface radiation on heat transfer and laminar natural convection in a cavity model partially filled with a porous medium are studied numerically. Unsteady natural convection and heat transfer model with surface radiation are constructed by two regional models, and finite element method is utilized to solve mathematical model, and numerically simulate the changing of flow field and temperature over time. The surface thermal radiation will increase the interior natural-convection heat transfer. With various boundary conditions of winter and summer, the different locations of intermediate layer and the top layer can change the indoor thermal environment. The thickness, d, of the porous medium has a significant effect on heat transfer. The most desirable insulating effect can be achieved by partially filling instead of entirely filling the enclosure.