Experimental investigation into flow boiling heat transfer in ribbed micro-channel with porous-decorated sidewalls

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL International Journal of Thermal Sciences Pub Date : 2025-08-01 Epub Date: 2025-03-23 DOI:10.1016/j.ijthermalsci.2025.109883

Zitao Zhang , Kailu Cui , Haoteng Zhao , Tainuo Han , Kun He , Xin Yan

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Abstract

Micro-channel heat sinks with porous structures have attracted significant attention due to their capability in promoting nucleation and postponing local dry-out on heat transfer surfaces. However, research focusing on flow boiling in micro-channels with porous-decorated sidewalls remains limited, and the effects of porous coating thickness on the flow boiling heat transfer and bubble dynamics remain unclear. In this study, ribbed micro-channels with porous-decorated sidewalls (PDS-RMC) at two distinct thicknesses of porous-decorated sidewalls (i.e. 100 μm and 200 μm) were fabricated. The flow boiling heat transfer performance and pressure characteristics, as well as the flow regimes, within the PDS-RMCs were experimentally investigated and compared with those of the conventional smooth-ribbed micro-channel (SRMC) and porous-ribbed micro-channel (PRMC). Based on the visualization of bubble behavior within the micro-channels, the influence and mechanism of the PDS on the bubble dynamics and flow regime transitions in the micro-channels were investigated. The results indicated that a slip velocity between the bubbles and the near-wall fluid is generated within the PDS-RMCs due to the capillary pressure acting on the near-wall fluid, thereby reducing the resistance to fluid motion within the porous region. When the fluid within the channel is subcooled, the pressure drop in the 100 μm PDS-RMC is 75 % of that observed in the SRMC. After the onset of flow boiling, the growth rate of bubble slugs in the 100 μm PDS-RMC is 27.9 % higher than in the SRMC. The average bubble velocity in the 100 μm PDS-RMC is approximately two times that in the SRMC. A large amount of vaporization nuclei for bubble nucleation are generated on the porous coatings of the 100 μm PDS-RMC without significantly increasing the resistance to bubble expelling from the porous structure into the flow channel, thus enhancing the heat transfer capacity of the micro-channel. Compared to the SRMC, the heat transfer coefficient in 100 μm PDS-RMC has increased by 60.6 %, while those in the 200 μm PDS-RMC and the PRMC have been improved by 15.8 % and 11.3 %, respectively.

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多孔肋微通道流动沸腾换热实验研究

多孔结构的微通道散热器由于具有促进传热表面成核和延缓局部干化的能力而受到广泛关注。然而，针对多孔壁微通道内流动沸腾的研究仍然有限，多孔涂层厚度对流动沸腾传热和气泡动力学的影响也不清楚。在本研究中，在两种不同厚度的多孔侧壁（即100 μm和200 μm）上制备了具有多孔侧壁装饰的肋状微通道（PDS-RMC）。实验研究了pds - rmc内部的流动沸腾换热性能、压力特性以及流动状态，并与传统的光滑肋微通道（SRMC）和多孔肋微通道（PRMC）进行了比较。基于微通道内气泡行为的可视化，研究了PDS对微通道内气泡动力学和流型转变的影响及其机理。结果表明，由于毛细管压力作用于近壁流体，在PDS-RMCs内气泡与近壁流体之间产生滑移速度，从而降低了孔隙区域内流体运动阻力。当通道内流体过冷时，100 μm PDS-RMC中的压降为SRMC中的75%。流动沸腾开始后，100 μm PDS-RMC中气泡段塞的生长速率比SRMC高27.9%。100 μm PDS-RMC的平均气泡速度约为SRMC的2倍。在100 μm PDS-RMC多孔涂层上生成了大量的汽化核用于气泡成核，但并未显著增加气泡从多孔结构向流道排出的阻力，从而增强了微通道的换热能力。与SRMC相比，100 μm PDS-RMC的换热系数提高了60.6%，200 μm PDS-RMC和PRMC的换热系数分别提高了15.8%和11.3%。

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来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.