A Study on the Performances of Solar Air Collectors Having a Hemispherical Dimple on the Absorber Plate  

作　　者：Shuilian Li Fan Zeng Xinli Wei 

机构地区：[1]School of Architecture and Environmental Engineering,Zhengzhou Technical College,Zhengzhou,450121,China [2]School of Mechanical and Power Engineering,Zhengzhou University,Zhengzhou,450001,China

出　　处：《Fluid Dynamics & Materials Processing》2024年第5期939-955,共17页流体力学与材料加工（英文）

基　　金：the Key Scientific Research Projects of Colleges and Universities in Henan Province(22B480007).

摘　　要：In order to increase the efficiency of solar air collectors,a new variant with a protrusion is proposed in this study,and its performances are analyzed from two points of view,namely,in terms of optics and thermodynamics aspects.By comparing and analyzing the light paths of the protrusion and the dimple,it can be concluded that when sunlight shines on the dimple,it is reflected and absorbed multiple times,whereas for the sunlight shining on the protrusion,there is no secondary reflection or absorption of light.When the lighting area and the properties of the surfaces are the same,the absorption rate of the dimple is 10.3 percentage points higher than that of the protrusion.In the range of Reynolds number from 3000 to 11000,numerical simulations about the effects of the relative height(e/Dh=0.033–0.1)and relative spacing(p/e=4.5–8.5)of protrusions on air heat transfer and flow resistance show that,in terms of comprehensive evaluation coefficient(PF),the best relative height is 0.085,when the relative spacing is 5.A correlation of Nu and f with Re,e/Dh and p/e is obtained by linear regression of the results,in order to provide a useful reference for the design and optimization of this kind of solar air collector.

关 键 词：Heat transfer hemispherical protrusion DIMPLE solar air collector CORRELATION 

分 类 号：TK515[动力工程及工程热物理—热能工程]