A channel layout of a flat-plate micro pulsating heat pipe (MPHP) for an excessively localized heating condition is proposed. The excessively localized heating condition is implemented using a small heater, which covers only about 2% of the whole area, in the middle of the bottom part. To simplify the heat transfer characteristics in MPHPs, the channel regions are modeled as a region with the high effective thermal conductivity, and the topology optimization method is employed to determine a distribution of the channel regions of the MPHP. The constraints on the maximum length scale and the minimum solid volume fraction in local regions are imposed to take into account the operational characteristics of MPHPs. In the proposed channel layout, which is inspired by the topology optimization result, the channels are laid out in such a way that some channels are merged to reduce the number of channels. Due to a decrease in the number of channels, all channels are able to overlap the localized heating section without any thermally-isolated channel. To verify the effectiveness of the proposed method, the MPHPs with the channel layout designed by topology optimization and two kinds of channel layouts for the references are fabricated, and their flow characteristics and thermal performances are experimentally compared. In case of the MPHP with the uniform channel layout, only 4 channels out of 18 channels overlap the heating section, and the stagnant liquid slugs in the thermally-isolated channels are observed. On the other hand, in the MPHP with the channel layout designed by topology optimization, all channels overlap the heating section, and the active oscillating motion of the liquid slugs occurs in all channels. This allows the MPHP with the channel layout designed by topology optimization to have about two times higher thermal performance than the MPHP with the uniform channel layout. In this study, the channel layout of the MPHP for the excessively localized heating condition is firstly suggested, and the experimental results show that the proposed channel layout can effectively overcome the limitation associated with the localized heating condition.

提出了一种用于过度局部加热条件的平板微脉动热管 (MPHP) 的通道布局。过度局部加热条件是使用一个小加热器来实现的，该加热器仅占整个区域的 2% 左右，位于底部的中间。为了简化MPHP的传热特性，将通道区域建模为具有高有效导热率的区域，并采用拓扑优化方法确定MPHP通道区域的分布。考虑到 MPHP 的操作特性，对局部区域的最大长度尺度和最小固体体积分数施加了限制。在提议的通道布局中，受拓扑优化结果的启发，频道的布局方式是合并一些频道以减少频道数量。由于通道数量的减少，所有通道都能够与局部加热部分重叠，而无需任何热隔离通道。为了验证所提方法的有效性，制作了具有拓扑优化设计的通道布局和两种通道布局作为参考的MPHPs，并通过实验比较了它们的流动特性和热性能。在具有均匀通道布局的 MPHP 的情况下，18 个通道中只有 4 个通道与加热段重叠，并且在热隔离通道中观察到停滞的液体段塞。另一方面，在拓扑优化设计的通道布局的MPHP中，所有通道都与加热段重叠，并且液塞的主动振荡运动发生在所有通道中。这使得采用拓扑优化设计的通道布局的 MPHP 比采用统一通道布局的 MPHP 具有大约两倍的热性能。在本研究中，首次提出了针对过度局部加热条件的 MPHP 通道布局，实验结果表明，所提出的通道布局可以有效克服与局部加热条件相关的限制。