基于CFD的植物工厂圆形锯齿状水冷LED灯管降温效果模拟  

Numerical simulation of the cooling efficiency of circular serrated water-cooled LEDs using CFD in plant factory

作　　者：方慧[1,2] 程瑞锋 仝宇欣[1,2] 李琨 Fang Hui;Cheng Ruifeng;Tong Yuxin;Li Kun(Institute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agricultural Sciences,Beijing 100081,China;Key Laboratory of Energy Conservation and Waste Management of Agricultural Structures,Ministry of Agriculture and Rural Affairs,Beijing 100081,China)

机构地区：[1]中国农业科学院农业环境与可持续发展研究所,北京100081 [2]农业农村部设施农业节能与废弃物处理重点实验室,北京100081

出　　处：《农业工程学报》2021年第7期212-217,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：中央级公益性科研院所基本科研业务费专项(Y2020GH02)。

摘　　要：为及时将LED灯管芯片产生的热量传导出去,提升LED灯的性能,延长其使用寿命,设计了一种圆形锯齿状水冷LED灯管,并通过计算流体力学(Computational Fluid Dynamics,CFD)软件构建水冷LED灯管模型,对其降温效果进行研究。在模型中将LED灯珠芯片设置为内热源,热流密度根据灯珠的数量和电光转化效率计算,其值为1.7×10^(7) W/m^(3)。验证试验表明,模拟值与实测值吻合较好,最大误差为16.4%,构建的CFD模型能准确模拟灯管各结构的温度分布。利用验证的模型模拟不同水流速度对水冷LED灯管温度分布及水流压降的影响。结果表明:不同流速下水冷LED灯管的金属散热灯罩、灯珠芯片和水流的温度分布比较均匀,表明该灯管的结构设计合理,灯珠芯片释放的热量能很快传导到水流中并被带走;当灯管入口水流速度从0.10 m/s增加到0.25 m/s时,进出水温差从1.4℃下降到0.5℃。因此,在对水冷LED灯管进行串联时,可根据进水温度和环境温度的差来计算可串接灯管数量;入口水流速度的增加亦会增加水流阻力,根据模拟得到灯管进出水压差计算出灯管对水流的阻力系数为2.2,为水泵选型提供了依据。LEDs are more commonly used than fluorescent lamps in plant factories with artificial light for energy savings.But the LEDs cannot convert the input power to light at 100%efficiency.Part of energy can be converted into heat,and then be transferred to the ambient environment,in terms of heat conduction,radiation,and convection.However,heat dissipation of LEDs has become a great challenge,as the power increased while the volume of LEDs reduced.In this study,a circular serrated water-cooled LED was designed to transmit the heat generated by LEDs in time for a longer service life.A three-dimensional Computational Fluid Dynamic(CFD)model was developed to assess the design,where the LED bubbles were set as the internal heat source.The electrical efficiency was assumed to be 32%and 49%in the red and blue LEDs,respectively.The heat flux of 1.7×10^(7) W/m^(3) was calculated,according to the number of lamp beads and the electrical to light conversion efficiency.The constructed grids were approximately 1162800 for each case,including 220881 nodes with a minimum element size of 2 mm.Much finer meshes were automatically imposed near the bubbles with proximity and curvature size functions in meshing.The SIMPLE was selected for the pressure-velocity coupling.A least-square cell-based scheme was used for the gradient term in spatial discretization.The second-order scheme was applied for the pressure term.The second-order upwind discretization schemes were used for momentum and energy equations,whereas,the first-order upwind discretization schemes were used for turbulence equations,mainly for higher accuracy.The convergence criterion was set as 10-6 on energy and 10-3 on continuity,momentum and viscous terms.Inlet and outlet boundary conditions were set for the numerical solution using the velocity-inlet and pressure-outlet.The inlet water velocity and water temperature were set as 0.2 m/s and 24℃,respectively.The simulated value of the LED water-cooled lamp was close to the measured value,with the maximum error of 16.4%,indic

关 键 词：温度 计算流体力学 植物工厂 人工光源 模拟 水流速度 

分 类 号：S625.4[农业科学—园艺学]