Relation between triple phase contact line and vapor groove width for enhancing thermal performance of a loop heat pipe evaporator
Relation between triple phase contact line and vapor groove width for enhancing thermal performance of a loop heat pipe evaporator
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DOI：
10.1016/j.ijheatmasstransfer.2022.123139
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发表时间：
2022
影响因子：
5.2
通讯作者：
Yoshihisa Nakatsugawa;K. Odagiri;A. Ueno;H. Nagano
中科院分区：
文献类型：
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作者：
Yoshihisa Nakatsugawa;K. Odagiri;A. Ueno;H. Nagano
在这项研究中，增加蒸发面积称为三相接触线（TPCL）的多孔芯和改善蒸发器的润湿性上的环路热管（LHP）的传热性能的影响进行了实验和理论评估。利用红外摄像机和显微镜对不同蒸汽槽宽度的多孔芯和不同内壁结构的蒸发器加热板的热流体行为进行了实验研究。多孔芯的蒸汽槽宽度为1.0 mm、0.5 mm和0.2 mm。普通加热板和微槽加热板用作蒸发器壳体。结果，澄清了在加热板上加工微槽改善了蒸发传热系数和最大热通量，而与多孔芯的蒸气槽宽度无关。此外，有人提出，这两个显着增加的蒸汽槽宽度。建立了预测每种情况下传热系数的热工水力数值模型。计算结果表明，随着TPCL出现率的增加，换热系数显著增加，且这种增加趋势与实验结果吻合较好。此外，有人提出，TPCL出现率在高热流密度的蒸汽槽宽度减小而降低。研究结果为提高LHP蒸发器的传热性能提供了一条新的途径。
In this study, the effects of an increased evaporation area known as the triple-phase contact line (TPCL), of the porous wick and improved evaporator wettability on the loop heat pipe (LHP) heat transfer performance were evaluated experimentally and theoretically. An infrared camera and a microscope were used to observe the thermo-fluid behavior of porous wicks with different vapor grooves widths and evaporator heating plates with different inner wall structures in the experiment. The porous wick's vapor groove widths were 1.0 mm, 0.5 mm, and 0.2 mm. A normal heating plate and a micro-grooved heating plate were used as the evaporator case. As a result, it was clarified that processing the micro-grooves on the heating plate improved the evaporative heat transfer coefficient and maximum heat flux, regardless of the vapor grooves width of the porous wick. Furthermore, it was proposed that both of them increased significantly as the vapor grooves width increased. The thermal-hydraulic numerical model that predicted the heat transfer coefficients for each case was developed. The calculation results showed a significant increase in the heat transfer coefficient as the TPCL appearance rate, which expresses how much the TPCL appears in the micro-grooves, increased, and this increasing tendency was in good agreement with the experimental results. Furthermore, it was proposed that the TPCL appearance rate at a high heat flux was reduced as the vapor grooves width decreased. The results indicate a new promising approach for improving the heat transfer performance of LHP evaporators.