Enhancement of heat transmission for a magnetic fluid flow in a minichannel with corrugated walls and variable cross-section associated with a magnetic field
摘要
This research focuses on the numerical analysis of an active vortex generator designed to improve heat transmission of a magnetic nanofluid under the impact of an external magnetic field. The magnetic nanofluid used Fe3O4, with volume fractions of 0.5% and 1%, flows through a two-dimensional corrugated minichannel with a variable cross-section. Various simulations were accomplished for Reynolds numbers extending from 170 to 210 and magnetic field strengths from 0 to 1400 G. Two configurations were considered: one with a single source positioned at 15 mm and the other with two sources positioned at 7.5 mm and 15 mm from the inlet, respectively. The results demonstrate that the external magnetic field acts as a vortex generator, modifying the velocity distribution, improving fluid mixing and consequently intensifying convective heat transfer. The presence of permanent magnets significantly reduces the coefficient of friction by deflecting the ferrofluid toward the upper surface using an upward magnetic force. In the optimal situation, the Nusselt number can be intensified by a value of 44.45% and the pressure can decrease by 5.11%. For this investigation, thermal enhancement factor (TEF) exceeds one, meaning that results are promising. This highlights the crucial role of the magnetic field in enhancing heat transmission from a magnetic nanofluid flowing in a minichannel. These results have important implications, particularly for the study of blood flow in stenosed arteries by introducing nanoparticles.