DELTA WINGLETS FOR ENHANCING SOLAR ENERGY:TURBULENT STRAIN RATE-HEAT CONVECTION RELATIONSHIP  

作　　者：Yang Yang Siddharth Koushik Mohanakrishnan David S-K.Ting Steve Ray 

机构地区：[1]Turbulence and Energy Laboratory,University of Windsor,ON,Canada [2]Essex Energy,Oldcastle,ON,Canada

出　　处：《Journal of Green Building》2021年第2期97-114,共18页绿色建筑学报（英文）

摘　　要：Delta winglets are an effective means for enhancing heat exchange and thus the performance of renewable energy technologies,including solar energy.A pair of 0.1 mm thick,15 mm high(h)and 30 mm long aluminum winglets separated with transversal spacing,s,of 2h,h and 0 were scrutinized in a closed-loop wind tunnel at a Reynolds number based on h of 6300.The turbulent flow was characterized using a 3D hotwire probe,and the heat convection augmentation was quantified in terms of the normalized Nusselt number(Nu/Nu0),indicating the heat transfer improve-ment compared to the reference case without the winglets.The interaction of the organized counter-rotational vortices intensifies and they become indiscernible at s=0.The peak strain rate at 10h downstream increased from 390 s^(–1),to 478 s^(–1),to 514 s^(–1),when the spacing decreased from 2h to h to 0,respectively.The zero-spaced winglet pair provided the largest Nu/Nu0,of around 1.21,at X/h=10 and Y/h=0,approximately 21%higher than that of 2h-spaced winglet pair,due to the strongest strain rate and the absence of upwash flow.On the other hand,the 2h-spaced winglet pair provided the largest span-averaged Nu/Nu0,which is of practical significance.

关 键 词：delta-winglet pair turbulent strain rate heat transfer enhancement 

分 类 号：O35[理学—流体力学]