Numerical investigation of transient mixed convection of nanofluid in a cavity with non-Darcy porous inner block and rotating cylinders with harmonic motion

Nima Shirani,Davood Toghraie

doi:10.1038/s41598-021-96733-6

Nima Shirani, Davood Toghraie

Open Access

https://doi.org/10.1038/s41598-021-96733-6

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Journal: Scientific Reports	Publication Date: Aug 26, 2021
Citations: 14	License type: open-access

Affiliation: Islamic Azad University of Khomeynishahr

Abstract

Mixed convection of nanofluid in a 2D square enclosure with a porous block in its center and four rotating cylinders, which are forced by a simple harmonic function, was studied numerically. The porous zone was studied by considering the Forchheimer–Brinkman-extended Darcy model. Effects of various parameters including Darcy number (10–5 ≤ Da ≤ 10–2), porosity (0.2 ≤ ɛ ≤ 0.7), Richardson number (0.1 ≤ Ri ≤ 10), and volume fraction of nanoparticles (0 ≤ ϕ ≤ 0.03), on heat transfer, entropy generation, PEC, velocity, streamline and isotherm contours were demonstrated. The results show that decreasing the Darcy number as well as reducing the Richardson number leads to an increase in the average Nusselt number. However, porosity changes had no decisive effect on heat transfer. Maximize the volume fraction of copper nanoparticles in the base fluid enhanced heat transfer. In the case of the high permeability of the porous medium, the impact of the harmonic rotation of the cylinders on the flow patterns became more pronounced.

Highlights

Mixed convection of nanofluid in a 2D square enclosure with a porous block in its center and four rotating cylinders, which are forced by a simple harmonic function, was studied numerically
Streamline contours, isotherm contours, local and average Nusselt numbers, dimensionless velocity, entropy generation, and performance evaluation criteria (PEC) for different control characteristics mentioned above were presented in Figs. 4, 5, 6, 7, 8, 9, 10, and 11
The most marked feature of the chart is the growth of the average Nusselt number with adding solid volume fraction which is caused by the enhanced thermal conductivity of nanofluid

Summary

Introduction

Mixed convection of nanofluid in a 2D square enclosure with a porous block in its center and four rotating cylinders, which are forced by a simple harmonic function, was studied numerically. Alsabery et al.[11] studied entropy generation and heat transfer rate in a porous cavity with wavy boundaries and a rotating cylinder.

Results

Conclusion