百叶窗形叶片倾斜通道在变物性条件下自然对流换热系数数值模拟预测  

Numerical simulation prediction of heat transfer coefficient of natural convection from an array of slats with variable fluid-property conditions

作　　者：李安桂[1] 范向国[1] 

机构地区：[1]西安建筑科技大学环境与市政工程学院,陕西西安710055

出　　处：《西安建筑科技大学学报（自然科学版）》2006年第2期269-274,284,共7页Journal of Xi'an University of Architecture & Technology(Natural Science Edition)

基　　金：国家自然科学基金(50278057);陕西省教育厅专项科研计划项目(02JK121)

摘　　要：百叶窗形叶片作为强化自然对流换热的一种方式在制冷、空调及计算机部件散热等场合有着广泛的应用.对百叶窗形叶片端部开口的倾斜通道自然对流换热以及流动过程进行了较详细的数值模拟,在考虑了变物性的影响条件下,给出了换热系数的预测公式.模拟研究表明,一般情况下上部的两个通道,通道空气质量流量随叶片温度升高,先增大后减小,变物性的影响不可忽略.百叶窗形叶片从底部叶片到顶部叶片换热情况逐渐恶化.叶片上下面的局部努塞数,一开始在通道入口沿流动方向减小,在接近通道出口处又增大,并且叶片下表面局部努塞数增大的值大于叶片上表面增大的值.这一现象用一种新理论———场协同理论进行了解释.As a means of natural convection heat transfer enhancement, an array of slats have been widely applied to heat exchangers in air conditioning and refrigeration engineering areas. Natural convection heat transfer from open-ended inclined channels formed by an array of slats is simulated numerically as the variable fluid-property is taken into consideration. The correlations of the natural convection coefficient are predicted. It is found that air mass fluxes between the upper two channels change sharply as the slat surface temperature increases. Numerical study shows that the influence of the variable fluid-property ought not to be ignored. The heat transfer of a slat is dampened from the bottom slat to the top slat. The Local Nusseh, numbers of the slats decrease at the ingresses of channels, formed by an array of the slats, however increase at the exits of channels. The local Nusselt number at the lower surfaces of slats increase much more than at the upper surfaces of slats. Moreover, this phenomenon has been demonstrated well in terms of a new theory--the field synergy principle.

关 键 词：变物性 百叶窗叶片 场协同理论 自然对流 

分 类 号：TU834.35[建筑科学—供热、供燃气、通风及空调工程]