Flow and heat transfer enhancement of ferrofluid in rectangular channels induced by magnetic field
In order to comprehensively investigate the flow and heat transfer performance of ferrofluid in rectangular ducts under external magnetic field,numerical simulations were conducted based on the finite volume method.The impact of Reynolds number Re and magnetic field strength B on Nusselt number Nu and fluid friction factor f was analyzed.The characteristics of swirling flow induced by magnetic field,the effect of heat transfer enhancement and the comprehensive enhancement performances were emphatically compared under three different thermal boundary conditions.The results indicate that when an external magnetic field acts on the ferrofluid,the swirling flow with different structures of the ferromagnetic fluid in the rectangular channel for three different thermal boundary conditions is generated due to the synergistic effect of magnetic field,flow field and temperature field,which enhances heat transfer significantly.Moreover,the greater the applied B,the better the enhanced heat transfer effect and the better overall performance.Within the scope of the study,the comparison of the results for three thermal boundary conditions shows that the maximum comprehensive strengthening factors for four sides heating,upper and lower surface heating,and bottom surface heating are 1.372,2.277 and 2.299,respectively.
ferrofluidsrectangular channelmagneticheat transfer enhancementswirling flow
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