Features of nitrogen boiling dynamics on microstructured porous coatings

IF 0.5 4区工程技术 Q4 ENGINEERING, AEROSPACE

Thermophysics and Aeromechanics Pub Date : 2024-12-13 DOI:10.1134/S0869864324030107

D. V. Kuznetsov, A. N. Pavlenko

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Abstract

The effect of capillary-porous coatings obtained by the method of directed plasma spraying on the dynamics of evaporation and heat transfer during nitrogen boiling under conditions of steady-state heat release on copper tubular heaters with a diameter of 16 mm was experimentally studied. It is shown that the presence of coatings leads to an increase in the critical heat flux relative to a smooth heater and heat transfer intensification by the factor of up to 3.5 in the region of low heat fluxes. According to the analysis of high-speed video filming, intensification of heat transfer at low heat fluxes is associated with a significant activation of stably operating nucleation sites. With a subsequent increase in the heat load, intensification relates to a significant contribution of high-intensity heat transfer in the macro-layer zone in local areas between the ridges of structured coatings. It is shown that there is a decrease in the slope of boiling curves of the modified heaters in the pre-crisis regimes, determined by the pulsating behavior of interfaces and accompanied by significant fluctuations in the surface temperature.

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微结构多孔涂层上的氮沸腾动力学特征

实验研究了通过定向等离子喷涂方法获得的毛细管多孔涂层对直径为 16 毫米的铜管加热器在稳态放热条件下氮气沸腾过程中蒸发和传热动力学的影响。结果表明，相对于光滑的加热器，涂层的存在会导致临界热通量的增加，在低热通量区域，热传导强度最高可达 3.5 倍。根据高速视频拍摄分析，低热通量下的传热强化与稳定运行的成核点的显著激活有关。随着热负荷的增加，热传导的加强与结构涂层脊之间局部区域的大层区域高强度热传导的显著贡献有关。研究表明，在危机前状态下，改良加热器的沸腾曲线斜率会下降，这是由界面的脉动行为决定的，并伴随着表面温度的显著波动。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Thermophysics and Aeromechanics THERMODYNAMICS-MECHANICS

CiteScore

0.90

自引率

40.00%

发文量

审稿时长

>12 weeks

期刊介绍： The journal Thermophysics and Aeromechanics publishes original reports, reviews, and discussions on the following topics: hydrogasdynamics, heat and mass transfer, turbulence, means and methods of aero- and thermophysical experiment, physics of low-temperature plasma, and physical and technical problems of energetics. These topics are the prior fields of investigation at the Institute of Thermophysics and the Institute of Theoretical and Applied Mechanics of the Siberian Branch of the Russian Academy of Sciences (SB RAS), which are the founders of the journal along with SB RAS. This publication promotes an exchange of information between the researchers of Russia and the international scientific community.