Experimental evaluation of forced covective heat transfer of Fe3O4 ferrofluid in a U _ shaped tube under variable magnetic field

In this paper, the hydrodynamic and thermal behavior of〖 Fe〗_3 O_4ferrofluid flow in a horizontal U-shaped copper tube on a surface, is studied experimentally under the effect of a variable magnetic field. The ferrofluid flowed at a low Reynolds value through a U-shaped tube under the thermal boundary conditions of the tube with uniform heat flux affected by magnetic field in some regions. The purpose of the study was the empirical investigation of the effects of using nanofluid, volume percentage of nanoparticles, and frequency on variable magnetic field, and the effect of constant magnetic field on ferrofluid behavior in three regions of the tube, namely straight inlet, curvature, and straight outlet sections. Analysis of the percentage of impact of each parameter in different sections showed that the variable magnetic field had the greatest impact by increasing the volume percentage of nanoparticles in the straight inlet section of the tube by 8.8 % at a frequency of 50 Hz.