Alsabery Ammar I, Tayebi Tahar, Abosinnee Ali S, Raizah Zehba A S, Chamkha Ali J, Hashim Ishak
Refrigeration & Air-conditioning Technical Engineering Department, College of Technical Engineering, The Islamic University, Najaf 54001, Iraq.
Faculty of Sciences and Technology, Mohamed El Bachir El Ibrahimi University, Bordj Bou Arreridj, El-Anasser 19098, Algeria.
Nanomaterials (Basel). 2021 May 13;11(5):1277. doi: 10.3390/nano11051277.
A numerical study is presented for the thermo-free convection inside a cavity with vertical corrugated walls consisting of a solid part of fixed thickness, a part of porous media filled with a nanofluid, and a third part filled with a nanofluid. Alumina nanoparticle water-based nanofluid is used as a working fluid. The cavity's wavy vertical surfaces are subjected to various temperature values, hot to the left and cold to the right. In order to generate a free-convective flow, the horizontal walls are kept adiabatic. For the porous medium, the Local Thermal Non-Equilibrium (LTNE) model is used. The method of solving the problem's governing equations is the Galerkin weighted residual finite elements method. The results report the impact of the active parameters on the thermo-free convective flow and heat transfer features. The obtained results show that the high Darcy number and the porous media's low modified thermal conductivity ratio have important roles for the local thermal non-equilibrium effects. The heat transfer rates through the nanofluid and solid phases are found to be better for high values of the undulation amplitude, the Darcy number, and the volume fraction of the nanofluid, while a limit in the increase of heat transfer rate through the solid phase with the modified thermal ratio is found, particularly for high values of porosity. Furthermore, as the porosity rises, the nanofluid and solid phases' heat transfer rates decline for low Darcy numbers and increase for high Darcy numbers.
本文针对一个具有垂直波纹壁的腔内的热自由对流进行了数值研究，该腔壁由固定厚度的固体部分、一部分填充纳米流体的多孔介质以及第三部分填充纳米流体组成。以氧化铝纳米颗粒水基纳米流体作为工作流体。腔的波浪形垂直表面承受各种温度值，左侧为热，右侧为冷。为了产生自由对流，水平壁保持绝热。对于多孔介质，采用局部热非平衡（LTNE）模型。求解问题控制方程的方法是伽辽金加权残值有限元法。结果报告了有效参数对热自由对流流动和传热特性的影响。所得结果表明，高达西数和多孔介质的低修正热导率比对于局部热非平衡效应具有重要作用。发现对于波动幅度、达西数和纳米流体体积分数的高值，通过纳米流体和固相的传热速率更好，而发现随着修正热比，通过固相的传热速率增加存在极限，特别是对于高孔隙率值。此外，随着孔隙率增加，对于低达西数，纳米流体和固相的传热速率下降，而对于高达西数则增加。
