Purpose

The purpose of this study is to numerically investigate the geometric influence of different corrugation profiles (rectangular, trapezoidal and triangular) of varying heights on the flow and the natural convection heat transfer process over isothermal plates.

Design/methodology/approach

This work is an extension and finalization of previous studies of the leading author. The numerical methodology was proposed and experimentally validated in previous studies. Using OpenFOAM® and other free and open-source numerical-computational tools, three-dimensional numerical models were built to simulate the flow and the natural convection heat transfer process over isothermal corrugation plates with variable and constant heights.

Findings

The influence of different geometric arrangements of corrugated plates on the flow and natural convection heat transfer over isothermal plates is investigated. The influence of the height ratio parameter, as well as the resulting concave and convex profiles, on the parameters average Nusselt number, corrected average Nusselt number and convective thermal efficiency gain, is analyzed. It is shown that the total convective heat transfer and the convective thermal efficiency gain increase with the increase of the height ratio. The numerical results confirm previous findings about the predominant effects on the predominant impact of increasing the heat transfer area on the thermal efficiency gain in corrugated surfaces, in contrast to the adverse effects caused on the flow. In corrugations with heights resulting in concave profiles, the geometry with triangular corrugations presented the highest total convection heat transfer, followed by trapezoidal and rectangular. For arrangements with the same area, it was demonstrated that corrugations of constant and variable height are approximately equivalent in terms of natural convection heat transfer.

Practical implications

The results allowed a better understanding of the flow characteristics and the natural convection heat transfer process over isothermal plates with corrugations of variable height. The advantages of the surfaces studied in terms of increasing convective thermal efficiency were demonstrated, with the potential to be used in cooling systems exclusively by natural convection (or with reduced dependence on forced convection cooling systems), including in technological applications of microelectronics, robotics, internet of things (IoT), artificial intelligence, information technology, industry 4.0, etc.

Originality/value

To the best of the authors’ knowledge, the results presented are new in the scientific literature. Unlike previous studies conducted by the leading author, this analysis specifically analyzed the natural convection phenomenon over plates with variable-height corrugations. The obtained results will contribute to projects to improve and optimize natural convection cooling systems.

中文翻译：

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变高度波纹板三维自然对流换热数值研究

目的

本研究的目的是数值研究不同高度的不同波纹轮廓（矩形、梯形和三角形）对等温板流动和自然对流换热过程的几何影响。

设计/方法论/途径

这项工作是主要作者之前研究的延伸和定稿。数值方法是在之前的研究中提出并通过实验验证的。使用 OpenFOAM® 和其他免费开源数值计算工具，建立三维数值模型来模拟具有可变和恒定高度的等温波纹板的流动和自然对流换热过程。

发现

研究了波纹板不同几何排列对等温板流动和自然对流换热的影响。分析了高度比参数以及由此产生的凹凸轮廓对参数平均努塞尔数、校正平均努塞尔数和对流热效率增益的影响。结果表明，总对流换热和对流热效率增益随着高度比的增加而增加。数值结果证实了先前的发现，即增加传热面积对波纹表面热效率增益的主要影响，而不是对流动造成的不利影响。在具有凹形轮廓的高度的波纹中，具有三角形波纹的几何形状呈现出最高的总对流热传递，其次是梯形和矩形。对于具有相同面积的布置，事实证明，恒定和可变高度的波纹在自然对流换热方面大致相同。

实际影响

结果使人们能够更好地了解具有不同高度波纹的等温板的流动特性和自然对流换热过程。所研究的表面在提高对流热效率方面的优势得到了证明，有可能用于仅通过自然对流的冷却系统（或减少对强制对流冷却系统的依赖），包括微电子、机器人、物联网（IoT）、人工智能、信息技术、工业4.0等

原创性/价值

据作者所知，所提出的结果在科学文献中是新的。与主要作者之前进行的研究不同，该分析专门分析了具有可变高度波纹的板上的自然对流现象。获得的结果将有助于改善和优化自然对流冷却系统的项目。