Numerical study on the steady-state heat transfer rate of nanofluid filled within square cavity in the presence of oriented magnetic field

Abstract

In this paper, the steady-state natural convection in a square cavity filled with water–Al2O3 nanofluid in the presence of magnetic fields with variable inclination angles is investigated numerically. The enclosure is subjected to different side-wall temperatures while the top and bottom walls are assumed to be adiabatic. The thermal behavior of enclosure is assessed using a finite volume-based computer program. In order to ensure the accuracy of results, comparisons are also made with a previous published work. In this research, at constant magnetic field strengths, the effect of magnetic field inclination angle on the rate of heat transfer in the square cavity is investigated at the Rayleigh numbers of Ra = 103, 104, 105 and 106. In this work, the Hartmann number ranges from Ha = 0 to 120 and the solid volume fraction varies from φ = 0 to 0.06. Numerical results show that depending on the Rayleigh and Hartmann numbers, the maximum heat transfer rate may occur at magnetic field inclination angles of 45°, 60° or 90° and the effect of magnetic field inclination angle is significant at high values of Rayleigh and Hartmann numbers. It is found that addition of nano-sized solid particles causes higher heat transfer rate when Ra = 103, whereas at Rayleigh number of Ra = 106, a reverse behavior is observed. Results show that at Rayleigh numbers of Ra = 104 and 105, the effect of solid particles addition on the thermal performance of the enclosure depends on the Hartmann number. It is also shown that an increase in the inclination angle causes higher velocity within the enclosure and addition of solid particles leads to suppression of flow field.

On the suitability of the volume-averaging approximation for the description of thermal expansion coefficient of nanofluids

“…nf nf ¼ p p þ 1 À ð Þ f f Þ cannot properly explain thermal expansion coefficient of Al 2 O 3 -water nanofluid, no further improvement has been addressed to this correlation and this expression is in common use in the study of nanofluids (e.g. Sun and Pop, 2 Teamah and El-Maghlany, 3 Chamkha and Ismael, 4 Nasrin and Alim, 5 Sheikhzadeh et al, 6 and Koopaee et al 7 ).…”

“…Sun and Pop, 2 Teamah and El-Maghlany, 3 Chamkha and Ismael, 4 Nasrin and Alim, 5 Sheikhzadeh et al., 6 and Koopaee et al. 7 ).…”

Heat and mass source effect on MHD double-diffusive mixed convection and entropy generation in a curved enclosure filled with nanofluid

“…Their result showed that the presence of a magnetic field adversely affects the fluid flow, and heat transfer rate increases and decreases with the increase of the Rayleigh number and Hartmann number, respectively. Extensive research has been performed considering the effect of magnetic fields on fluid flow inside a cavity [15,30].…”

Effect of Magnetic Field Orientation on Nanofluid Free Convection in a Porous Cavity: A Heat Visualization Study

“…Recent years have witnessed an extensive study on heat transfer of nanofluids as a consequence of their appropriate thermophysical properties (eg., Mahfoud and Bendjaghloli [10]; Singh et al [11]; Zahmatkesh and Naghedifar [12]; Zahmatkesh and Torshizi [13]; Zahmatkesh and Habibi [14]). Although a significant number of investigations on MHD free convection of nanofluids in cavities are available in the literature (e.g., Koopaee et al [15,16], Akinshilo and Ilegbusi [17]), only a few recent studies have considered this problem in porous media.…”