基于LED灯具热流场分布均匀化的散热设计

Thermal Design of LED Luminaires Based on Uniform Distribution of Heat Flow Field

本文首先运用耦合传热理论与EFD软件,对一种LED灯具的温度场、流场、压强场进行仿真,再对仿真结果图进行图像处理,提取热流场分布的边缘曲线,并以此曲线方程为依据,在总重量不变的情况下,设计了一种曲线型散热结构,可以使热流场分布均匀化,并且更有效地利用周围空气进行散热。结果表明,在20℃环境中,曲线型散热结构可使最高温升降低12℃,最大相对压强减小0.95 Pa,流场流速分布更均匀,且居于较大流速的流体比例有明显提高。为进一步简化模型,又将曲线形状的翅片优化为逐渐向两边外侧倾斜的角度型翅片,使优化后的最高温度较曲线型又下降了7.1℃。最后通过实验对比证明角度型散热结构具有更好的散热效果,且减少了对生产加工工艺的要求。

Coupled heat transfer theory and EFD software are used to simulate the temperature field, flow field and pressure field of LED luminaire. According to the simulation result, the edge curve of heat flow field is extracted by image processing. After that, a model of new heat sink with curve shaped fins and the same weight is build based on the equation of the edge curve. This kind of structure could achieve uniform distribution of heat flow field, and make full use of ambient air to take away the heat faster. Simulation results show that, when ambient temperature is 20℃, the structure with curve shaped fins reduces highest temperature by 12℃, and highest relative pressure by 0.95 Pa. At the same time, flow velocity become more well-distributed, with much more fluid at higher flow rate. To further simplify the model, the curve shaped fins are optimized to inclined fins gradually tilting from the center to the sides. After the optimization, highest temperature drop by 7.1℃, compared with the former one. At last, contrast experiment is done to prove that the heat sink with inclined fins presents better cooling efficiency, and at the same time, has lower requirement for production and processing technology.