03. Electronics Packaging and Thermal Management

Owing to the rapid development of B5G or 6G telecommunication, the heat generated from the power module of the communication satellites increased drastically in the past years. The thermal solution of how to dissipate heat from the power module became an important issue for further improving the performance of these systems. Copper-water heat pipes are popularly used for most of the electronic devices cooling systems. However, in the space applications, the environment temperature can be as low as -40 ℃. Water may freeze and let the heat pipe not be able to operate normally at temperature below 0 ℃. In addition, owing to the expansion of water during the freezing process, the sintered porous wick may be peeled off from tube wall and resulted in the failure of the heat pipe. This study conducted an experimental observation on the heat transfer performance of sintered copper-water heat pipe with various wick thicknesses and filling ratios under freezing-thawing cyclic operation. The heat pipe was operated at -40 oC for 12 hours and increased to 80 oC for another 12 hours to complete a operation cycle. The test results showed that heat pipes with wick thickness of 0.9 mm and filling ratio of 80% exhibited the lowest thermal resistance. The heat pipe worked normally after 172 freezing-thawing cycles. No significant heat transfer performance degradation was observed.