Conjugate natural convection flow under magnetic field in an enclosure with a square tube

In this study, natural convection heat transfer in a tube inserted square cavity in the presence of longitudinally applied magnetic field was investigated numerically by using control volume method. The side walls of the cavity were kept at constant temperatures while the top and the bottom walls were insulated. A square tube with zero thickness as an inner enclosure was located inside the square cavity. Both the inner and outer enclosures were filled with the same fluid having a Prandtl number of unity. The results were presented in the form of streamlines, isotherms, and Nusselt number for various Hartmann numbers and different locations of square tube. The results indicated that both the magnetic field and off-center square tube can significantly affect the flow and temperature fields. Circulation inside the enclosures and therefore the convection became weaker as the higher magnetic field suppressed the convective flow and the heat transfer rate. By inserting the tube, the overall heat transfer decreased due to increase of theresistance to the fluid motion. It was found that varied location of the tube center can lead to different flow fields and heat transfer intensities.

Keywords:

conjugated heat transfer , magnetic field , natural convection , Hartmann number , MHD