为了增强LED灯具的散热能力,根据烟囱效应原理,设计了一种LED球泡灯,其具有特殊的直筒式烟囱结构。利用Solidworks建立三维模型,通过其插件Flow Simulation进行热仿真,并以烟囱高度30 mm、烟囱数量6、通风口长度2 mm的参数为基础模型。通过实验验证,测出该模型的最高温度为69 ℃,与仿真所得出的结果仅相差1.66 ℃,证实了仿真步骤的正确性。以此为基础,对不同烟囱高度和数量、通风口大小对LED芯片最高温度的影响进行研究。研究表明：烟囱效应明显增强了灯具的对流散热性能。在烟囱高度为45 mm、烟囱数量为12、通风口长度为3.5 mm时,LED芯片的最高温度为61.04 ℃,比优化前下降了9.62 ℃。在模型参数相同的条件下,最高温度比不加烟囱结构的LED球泡灯下降了1.9 ℃,且散热器重量下降了2.55 g。在自然对流条件下,所设计的LED球泡灯能很好地满足LED芯片工作要求。

In order to enhance the cooling capacity of LED lamps and lanterns, we design a special LED bulb with straight chimney structure based on the principle of the chimney effect. We build a three-dimensional model by adopting Solidworks, and use its plug called Flow Simulation to simulate based on the model with the chimney height of 30 mm, chimney number of 6, and vent length of 2 mm. Through experiments, we find the highest temperature of this model is 69 ℃, lower than the simulation result only 1.66 ℃. It confirms the correctness of the simulation steps. Then, we study the influences of different chimney height, chimney number, and vent length on the highest temperature of LED bulb, respectively. The results show that the chimney effect can effectively improve the convection cooling performance of the LED bulb. When the chimney height is 45 mm, chimney number is 12, and vent length is 3.5 mm, the highest temperature of the LED chip is 61.04 ℃, which is 9.62 ℃ lower compared to the original model. Under the same set of model parameters, the highest temperature of the LED bulb has been reduced by 6.16 ℃ compared to the one in the model without a chimney structure, and the weight of radiator has also reduced 2.55 g. In conclusion, the designed LED bulb can better satisfy the working requirements under the nature convection conditions.