Purpose

This paper aims to use the Lattice Boltzmann method (LBM) to numerically simulate the natural convection heat transfer of Cu-water nanofluid in an L-shaped enclosure with curved boundaries.

Design/methodology/approach

LBM on three different models of curved L-shape cavity using staircase approach is applied to perform a comparative investigation for the effects of curved boundary on fluid flow and heat transfer. The staircase approximation is a straightforward and efficient approach to simulating curved boundaries in LBM.

Findings

The effect of curved boundary on natural convection in different parameter ranges of Rayleigh number and nanoparticle volume fraction is investigated. The curved L-shape results are also compared to the rectangular L-shape results that were also achieved in this study. The curved boundary LBM simulation is also validated with existing studies, which shows great accuracy in this study. The results show that the top curved boundary in curved L-shape models causes a notable increase in the Nusselt number values.

Originality/value

Based on existing literature, there is a lack of comparative studies which would specifically examine the effects of curved boundaries on natural convection in closed cavities. Particularly, the application of curved boundaries to an L-shape cavity has not been examined. In this study, curved boundaries are applied to the sharp corners of the bending section in the L-shape and the results of the curved L-shape models are compared to the simple rectangular L-shape model. Hence, a comparative evaluation is performed for the effect of curved boundaries on fluid flow in the L-shape enclosure.

中文翻译：

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格子 Boltzmann 方法在 L 形外壳中模拟纳米流体流动的弯曲边界中的应用

目的

本文旨在使用格子玻尔兹曼方法 (LBM) 数值模拟铜水纳米流体在具有弯曲边界的 L 形外壳中的自然对流换热。

设计/方法/方法

采用阶梯法对三种不同的弯曲 L 形腔模型进行 LBM，对弯曲边界对流体流动和传热的影响进行了比较研究。楼梯近似是一种直接有效地模拟 LBM 中弯曲边界的方法。

发现

研究了在瑞利数和纳米粒子体积分数的不同参数范围内弯曲边界对自然对流的影响。弯曲的 L 形结果也与本研究中获得的矩形 L 形结果进行了比较。曲线边界 LBM 模拟也得到了现有研究的验证，这在本研究中显示出很高的准确性。结果表明，弯曲 L 形模型中的顶部弯曲边界导致努塞尔数值显着增加。

原创性/价值

根据现有文献，缺乏专门研究弯曲边界对封闭空腔自然对流影响的比较研究。特别是，尚未研究将弯曲边界应用于 L 形腔。在这项研究中，弯曲边界应用于 L 形弯曲截面的尖角，并将弯曲 L 形模型的结果与简单的矩形 L 形模型的结果进行了比较。因此，对弯曲边界对 L 形外壳中流体流动的影响进行了比较评估。