建筑外壁面换热系数对室内自然对流传热影响

Influence of the heat transfer coefficient of the outer-surface on the natural convective heat transfer characteristics in a heating room

为研究建筑外壁面换热系数与供暖室内自然对流换热的关联性,采用修正的湍流k-ε模型对外墙外壁面不同换热系数情况下的室内自然对流换热过程进行了数值分析并对比了热负荷值。结果表明:在满足室内供暖温度(18℃)要求条件下,考虑外界辐射和蒸发对外壁面换热过程的作用(外壁面换热系数取8.1 W·m-2·°C-1),所得散热器表面的换热能力要低于按照暖通设计规范取值(外壁面换热系数取23.3 W·m-2·°C-1)所得结果,两种取值方式对室内温度场和舒适性的影响很微弱,但所得室内热负荷之间的差异达到了6.2%。

To study the relationship between the outer surface heat transfer coefficient of an external wall and the natural convective heat transfer characteristics in a heating room in Lanzhou,a revised k-ε model was used to numerically analyze indoor natural convective heat transfer under different outer surface heat transfer coefficients of the external wall. The corresponding heat load was also compared. The results indicate that,under the conditions of18°C average indoor air temperature,and the outer surface heat transfer coefficient of the external wall is set to8.1 W·m^-2·°C^-1,the heat transfer ability of the radiator surface,considering outdoor radiation and evaporation,is less than that when the outer surface heat transfer coefficient of external wall is set to 23.3 W·m^-2·°C^-1,according to the HVAC design specification. Both values of the outer surface heat transfer coefficient of the external wall have very weak effects on the indoor temperature field and thermal comfort. However,the difference of calculated heat load between them has reached 6.2%.