Effects of vibrational flow on nanofluid flow behavior under different temperature boundary conditions

Abstract

A comparative study was conducted using a well-validated computational fluid dynamics (CFD) model to investigate the effects on heat transfer. The study focused on forced convection internal flow of both base fluid and nanofluid, subjecting them to different boundary conditions. Vibration was applied in the transverse direction to the flow. The simulations were performed with varying Reynolds numbers, volume fractions, vibration frequencies, and amplitudes. In order to improve the predictive capabilities of the computational fluid dynamics (CFD) model for single-phase flow systems, rheological properties dependent on temperature were incorporated. The introduction of transverse vibrations swiftly disrupted the thermal boundary layer, resulting in an axial temperature increase for low Reynolds number flows. Consequently, under constant wall temperature conditions, this led to heightened heat transfer rates. The observed enhancement in heat transfer rate, achieved through variations in volume fraction and particle diameter, aligned with typical behavior exhibited by nanofluids under steady-state flow. However, under vibrational conditions, the heat transfer enhancement surpassed that of the pure liquid significantly. As frequency levels rose, the impact of vibrations diminished, while changes in amplitude exerted a more pronounced influence. The most substantial increase, approximately 540%, was witnessed under vibrational flow conditions compared to steady-state flow. The ratio of the heat transfer coefficient was about 28% higher when the flow was subjected to uniform heat flux but under unsteady-state conditions. However, there was not much growth in the outlet temperature observed.