Abstract:

The traditional serpentine structure and topological structure flat plate pulsating heat pipes were made on alloy copper by wet etching technology. With R141b as the working fluid, the start-up and heat transfer performance differences and change laws of the above two heat pipes under local heating (heating area 15 mm×15 mm, 20 mm×20 mm and 25 mm×25 mm) were compared and studied. Experimental results show that both traditional and topological optimized OHPs exhibit improved start-up and heat transfer performance with increasing local heat source area. Compared to the traditional OHP, the topology-optimized design concentrates the channels around the local heat source, effectively expanding the evaporation/boiling area in the heating section and minimizing the influence of the heat source area on its start-up and thermal performance. For the traditional OHP with multiple local heat sources, the start-up behavior can be categorized into two types: 'abrupt' and 'gentle', which resemble the start-up characteristics observed with a single uniform heat source. In contrast, the topologically optimized OHP only displays a 'gentle' start-up behavior, with no abrupt temperature changes observed under any conditions. The topological design significantly improves the overall temperature uniformity and the heat transfer limit of the OHP, particularly improving heat transfer performance for smaller heat source areas and medium-low heating powers. For instance, when the heat source area is 15 mm×15 mm and the heating power is approximately 75 W, the effective thermal conductivity of the topologically optimized OHP increases by about 41.8% compared to the traditional design. The optimized channel layout mitigates the limitations of traditional OHPs in dissipating heat from multiple localized sources, offering superior temperature uniformity and heat transfer capacity, thus expanding the application potential of OHPs.

Key words: oscillating heat pipe, topological optimization, heat transfer, start-up characteristics, multiple heat sources

摘要：

借助湿刻技术在合金铜材上制作了传统蛇形结构和拓扑结构平板脉动热管，以R141b为工质，比较了上述两种热管在局部加热（加热面积15 mm×15 mm，20 mm×20 mm和25 mm×25 mm）情况下的启动与传热性能差异及变化规律。实验结果表明，传统型和拓扑型脉动热管的启动和传热性能均随着局部加热面积的增大而增强。相比于传统平板脉动热管，拓扑优化设计能够将热管通道集中分布在局部热源内，有效增大加热段蒸发/沸腾区域的面积，从而弱化热源面积对其启动和传热性能的影响。传统型脉动热管在多局部热源加热条件下的启动可分为“突变”和“平缓变化”两种方式，与单一均匀热源加热的启动方式相似，但拓扑型脉动热管在所有工况下的启动过程中均无温度突变行为。拓扑结构设计能够有效提高热管整体的均温性和传热极限，尤其是可以改善较小热源面积和中低加热功率下脉动热管的传热性能，在热源面积为15 mm×15 mm和加热功率约为75 W时，其有效热导率比传统热管提高约41.8%。具有拓扑优化通道的脉动热管能够弥补传统脉动热管在局部多热源散热应用中的不足，并表现出良好的均温性和传热极限，从而拓宽脉动热管的应用领域。

关键词: 脉动热管, 拓扑优化, 传热, 启动, 多热源