重庆理工大学学报2025，Vol.39Issue(19)：203-210,8.DOI:10.3969/j.issn.1674-8425(z).2025.10.025
肋筋微结构表面沸腾传热特性仿真研究
Simulation study on boiling heat transfer characteristics of ribbed micro-structure surfaces
摘要
Abstract
Internal combustion engines(ICEs)set increasing high standards for power,emissions and lightweight design.Extensive studies have confirmed the sub-cooled flow boiling heat transfer inside ICE cylinder heads,playing a critical role in enhancing the heat dissipation efficiency of ICEs and sustaining their long-term operation.Studies also prove micro-structured surfaces effectively strengthen boiling heat transfer.To meet the requirements for heat dissipation temperature in ICEs and achieve enhanced boiling heat transfer,this paper adopts a rib-shaped micro-structure to further improve the boiling heat transfer of heat exchange surfaces. A concave-convex symmetric rectangular rib-shaped microstructure is added to a rectangular channel,and the volume-of-fluid(VOF)method in Fluent software is employed to investigate how the variation and distribution of rib micro-structures affect flow boiling heat transfer characteristics in a two-dimensional rectangular channel.Numerical simulations are conducted to analyze bubble generation during the boiling heat transfer process in the rectangular channel with rib-shaped concave-convex micro-structures,examine changes in boiling curves and heat transfer coefficients,and explore the impacts of the size and distribution of rib-shaped concave-convex micro-structures(e.g.,width,height,and spacing)on boiling curves and heat transfer coefficients. Results reveal flow boiling heat transfer consistently involves bubble generation,growth,coalescence,and breakup.When cooling water flows through the channel,the concave-convex surface disrupts the flow,causing the cooling water temperature to gradually rise to the saturation temperature.Tiny bubbles,forming on both sides of the convex platforms and at the bottom of the concave grooves,continue to grow and coalesce as the flow progresses. Sub-cooled flow boiling heat transfer consists of two main stages.The first is the convective heat transfer stage,where the heat transfer curve tends to be linear.The second is the boiling heat transfer,where the slope of the heat transfer curve increases.A rise of the rib width results in improved heat transfer coefficient during the convective heat transfer stage while a decrease of rib width leads to better heat transfer during the boiling stage—and it decreases as the width increases.Specifically,a rib width of 0.05 mm delivers the optimal heat transfer,representing a maximum increase of 32.1％compared with the original model. In terms of rib height,lower ribs exhibit better heat transfer under high wall superheat,while higher ribs perform better under low wall superheat.A rib height of 0.05 mm enhances the heat transfer coefficient by a maximum of 25.0％compared with the original model.In terms of rib spacing,a smaller spacing cuts the time to initiate boiling and markedly improves heat transfer.As the spacing increases,the mutual influence between bubbles weakens,leading to a gradual decline in heat transfer.However,a further increase in spacing allows more fluid to flow through the heated wall,resulting in a slight improvement in boiling heat transfer.The optimal boiling heat transfer coefficient occurs at a rib spacing of 1 mm.These results may provide insights into how the size and distribution of rib micro-structures affect the boiling heat transfer of enhanced heat exchange surfaces.关键词
微结构/沸腾传热/强化传热/数值模拟Key words
microstructure/boiling heat transfer/enhanced heat transfer/numerical simulation分类
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邓晰文,徐中华,邓伟,杞卓玲,雷基林,贾德文..肋筋微结构表面沸腾传热特性仿真研究[J].重庆理工大学学报,2025,39(19):203-210,8.基金项目
云南省科技计划项目(202202AB080011) （202202AB080011）
