Entropy generation and heat transfer investigation of a nanofluid subject to an exponential magnetic field

• Entropy generation analysis and energy losses prediction for a nanofluid in a horizontal annulus. • The role of an exponential magnetic field on the thermal performance of a nanofluid. • The effects of heat generation/absorption parameter on the heat transfer rate of a nanofluid. Considering the nanofluid working through two coaxial cylinders, the particular contribution of the present work is to evaluate the combined effects of the heat generation/absorption and exponential magnetic field on the overall thermal performance. After reintroducing the non-dimensional form of governing equations, the Differential Quadrature Method is used as a numerical procedure to acquire the flow field characteristics. A suitable agreement is found by comparing the present findings with those from previous work. At the same Reynolds number, heat transfer rate increases by 24 % using A A 7072 nanoparticles, while 21 percent enhancement is reported for the heat transfer rate in the presence of Al 2 O 3 nanoparticles. Adding 0.1 percent nanoparticles to the base flow for the different heat generation/absorption parameters 1, 3, and 6, results in an improvement in the heat transfer rate to 21, 18, and 14 percent, respectively. Entropy generation is also a key factor in energy management in every thermal process. Therefore, entropy generation due to different heat generation/absorption and magnetic parameters is analyzed. Moreover, the role of heat transfer irreversibility on the overall energy losses is investigated.