基于计算流体动力学的LED车前灯热优化设计

Thermal Optimized Design of LED Headlamp Based on CFD

针对大功率阵列LED车前灯的散热节能问题，以计算流体动力学为理论依据，采用Ansys—icepak建模，仿真时以模型几何参数为变量、模型最高温度和质量为约束函数、模型热阻为目标函数，分别对LED汽车前照灯的插片式鳍片、圆柱式鳍片两种被动散热结构单模组进行设计、仿真和优化，结果表明，在初始环境温度85℃的相同边界条件下，优化后的插片式鳍片模型重量0．2756kg、最高温升12．52℃、热阻1．026℃／w，优于圆柱式鳍片模型，且符合LED车灯散热标准。整灯设计时，在车灯组前方底部设置进气格栅，在后上侧设置出气口，利用汽车向前行驶而产生的反方向风速加强内部对流，使车速在一档内的2m／s时整体温升就低于lO℃，有效提高了散热效率。

The paper focuses on the heat dissipation efficiency problem existed with LED automobile headlamps. Based on computational fluid dynamics, Ansys-icepak is used to build plug-in fin and cylindrical fin models for LED headlamp heat dissipation structures. During simulation and optimization, the model＇s geometric parameters are set as variables, highest temperature and mass are set as constraint functions, thermal resistance is set as objective function. The result indicates that under the same boundary condition with 85 Y; initial temperature, the plug-in fin model has mass of 0. 2756 kg, temperature rise of 12.52 ~C and thermal resistance of 1. 026 ~C/W, which is better than cylindrical fin model, and accords with the heat dissipation standard of LED headlamp. During design in headlamps, an input air grill and an outlet are arranged at the front bottom and upper back of the headlamp respectively, the opposite direction wind generated from the moving automobile is taken to strengthen internal convection. The results show that when velocity is 2 m/s in grade one, the temperature rise is less than 10 C, which reflects higher heat dissipation efficiency.