Natural convection heat transfer in a nanofluid filled L-shaped enclosure with time-periodic and field

The natural convective Cu-water nanofluid flow in L-shape cavity with an oscillating temperature profile is studied numerically. The cavity's lower horizontal and left vertical walls are heated sinusoidally with time about a high mean temperature ((T) over bar (H)). In contrast, the cavity's right vertical wall and its nearby horizontal lower wall are kept cold at a temperature (T-c). The calcula-tions have been performed over temperature oscillation amplitude (0 <= A <= 2), dimensionless temperature oscillation frequency (0 <= f <= 100), Rayleigh number (10(3) <= Ra <= 10(8)), Hartmann number (0 <= Ha <= 100), the nanoparticles volume fraction (0 <= phi <= 0.2), and enclosure aspect ratios (0.2 <= AR <= 0.8). Outcomes reveal that with AR = 0.2, heat transfer happens considerably through conduction at Ra = 10(3) - 10(5), while the time average Nusselt number ((N) over baru) is independent of both Ha and Ra. Convection effects, on the other hand, become significant at high Ra. Additionally, as Ha ascends from 0 to 50, (N) over baru increases linearly with increasing phi, while it remains steady at Ha = 75 and 100. (C) 2022 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University.

Automated summary

This paper numerically studies the natural convective flow of Cu-water nanofluid in an L-shaped cavity with oscillating temperature profile. The lower horizontal and left vertical walls of the cavity are heated sinusoidally, while the right vertical wall and its nearby horizontal lower wall are kept cold. Various parameters, including temperature oscillation amplitude, temperature oscillation frequency, Rayleigh number, Hartmann number, nanoparticles volume fraction, and enclosure aspect ratios, are considered. The results show that at a low aspect ratio, heat transfer mainly occurs through conduction, while convection becomes significant at high Rayleigh numbers. Additionally, the Nusselt number increases linearly with increasing nanoparticles volume fraction for a certain range of Hartmann numbers. (C) 2022 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University.