【摘要】 分析了现阶段建筑外表面对流换热研究存在的问题,设计了一种用于现场实测建筑外表面对流换热特性的萘升华方法,并利用该方法测量了某高大单体建筑水平屋面的对流换热特性.实测结果表明,建筑屋面的对流换热系数与屋面上方的代表风速成正比,代表风速在5.6m/s以内时,对流换热系数在5~50W/(m2.K).分析表明,萘试件表面的温度波动和屋面、空气之间的温差对实测结果影响不大.文中还考虑了建筑尺度对对流换热的影响,以风登陆屋面沿风向到测点的距离为代表长度,对实测结果做了无量纲化处理,得到了考虑到建筑尺度的建筑屋面对流换热无量纲准则.最后通过一个热平衡法的实验对文中提出的萘升华法做了验证.更多还原

【Abstract】 In this paper,some problems in the current researches on external convective heat transfer of buildings are analyzed,and a new naphthalene sublimation method is developed for the field measurement of external convective heat-transfer coefficient(CHTC) of building roof.Experimental results show that the CHTC of the roof is in a positive linear relation with the representive velocity of wind flowing on the roof,and that the CHTC ranges from 5 to 50 W/(m2·K) at a representive wind velocity of less than 5.6 m/s.Analytical results also indicate that the fluctuation of the temperature on the surface of naphthalene test specimens and the temperature difference between the air and the roof sligthly affect the measurement resluts.Moreover,by considering the influence of building dimensions and by choosing the distance from the roof edge to the measurement point as the representive length,a dimensionless corelation about the external convective heat-transfer characteristics is obtained.The effectiveness of the proposed naphthalene sublimation method is finally validated by a heat balance experiment.更多还原