Enhanced flow boiling heat transfer performance of diamond microchannels: An experimental study

Diamond microchannel heat sinks exhibit excellent cooling efficiency and good temperature uniformity, making them a key technology for the stable and efficient operation of future high-power electronic devices. However, it is still unknown how diamond microchannels improve the flow boiling heat transfer. In this study, diamond and silicon microchannels with identical geometries (widths of 100 μm and 200 μm, and a fixed depth of 250 μm) were fabricated to investigate the differences in flow boiling characteristics and heat transfer mechanisms. Flow boiling experiments were conducted under various mass flux conditions, and the bubble movement behavior and thermal performance were compared. The experimental results indicate that the diamond microchannels significantly increase the bubble departure frequency and enhance the heat transfer coefficient by up to 54.8 %, though at the expense of a higher pressure drop. The diamond microchannels reduce the wall superheat by 15.8 °C, lower the maximum chip temperature by 18.8 °C, and decrease the effective thermal resistance by 19.8 %, leading to a 30.0 % improvement in the comprehensive performance compared to their silicon counterparts. This work provides experimental evidence into the heat transfer enhancement mechanisms of diamond microchannels, offering a foundation for the development of next-generation cooling technologies for high-power electronics.