Heat Treatment of Metals ›› 2023, Vol. 48 ›› Issue (10): 50-58.DOI: 10.13251/j.issn.0254-6051.2023.10.007

• SPECIAL COLUMN • Previous Articles     Next Articles

Microchannel surface terminal and heat transfer performance of manifold all-diamond

Feng Xurui1, Wei Xinyi1, Zhang Jianjun1, Zheng Yuting1,2, Chen Liangxian1, Liu Jinlong1, Li Chengming1,2, Wei Junjun1,2   

  1. 1. Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China;
    2. Shunde Graduate School, University of Science and Technology Beijing, Foshan Guangdong 528399, China
  • Received:2023-06-28 Revised:2023-08-22 Online:2023-10-25 Published:2023-12-07

Abstract: Diamond thick film was prepared by DC arc plasma spraying, and Z-type manifold-type all-diamond microchannel was formed by high-energy laser. The diamond microchannel was treated with hydrogen plasma, acid and fluorine plasma to obtain hydrogen-terminal, oxygen-terminal and fluorine-terminal. Through the two-phase heat transfer experiment, the change mechanism of the surface modification technology in the sustained stability of the diamond microchannel radiator was analyzed. The researches find that in the process of constant heat flow treatment, with the increase of operating time, the hydrophobic properties of the hydrogen-terminated diamond microchannels decrease rapidly and are not suitable for heat transfer research. The hydrophilic properties of the oxygen terminal decrease significantly and then tend to be stable. The fluorine-terminated surface is the most stable, and its hydrophobicity remains constant after a slight decrease in the initial stage. At the same time, it is found that the heat transfer of the oxygen terminal and fluorine terminal manifold diamond microchannels is dominated by nuclear boiling, including bubble flow and elastic flow. After further heating, a large number of bubbles converge to form annular flow, and the evaporation of thin film is the dominant mechanism. The hydrophobic fluorine terminal microchannel will accelerate the nucleation of bubbles, and the heat transfer performance is better than that of fluorine terminal in flow boiling state. The excessive bubble formation causes the occurrence of reverse flow, and the oxygen terminal microchannel can delay the occurrence of reverse flow, showing a higher boiling starting point and critical heat flux. The heat transfer coefficient of the fluorine terminal microchannel is higher than that of the oxygen terminal in boiling state, so the fluorine terminal can be more suitable for the surface modification technology of preparing hydrophobic diamond heat sink.

Key words: manifold type, all-diamond microchannel, terminal stability, heat transfer performance

CLC Number: