Heat Transfer of Viscous MHD Nanofluid Flow in the Presence of Solar Radiation With Entropy

To satisfy the power needs of human beings without affecting the environment, scientists have been working on the efficient practices of renewable energy sources such as solar, water, and wind. As a source of energy resources, solar radiation is preferred because of its unlimited availability and low ecological impact. Thus, this article examines the heat transfer of unsteady electrically conducting viscous nanofluid flowing over a stretchable cylindrical surface in the presence of solar radiation. The entropy generation is also analyzed with the velocity slip and convective heat transfer boundary conditions. Considering Beer’s law for representing solar radiation, the horizontal cylindrical surface for nanofluid flow, and solving the model by the homotopy analysis method (HAM) can be the novelty of this study. The governing nonlinear partial differential equations (PDEs) are transformed into systems of higher‐order nonlinear ordinary differential equations (ODEs) using appropriate similarity transformations. These ODEs are then solved via the HAM, applying the BVPh2.0 package on Mathematica 12.1. Comparisons with previously published studies confirm the validity of the method and highlight its consistency. The results reveal that the presence of a magnetic field interaction slows down the flow while increasing both local skin friction and the temperature of the nanofluid. Solar radiation and the Eckert and Biot numbers enhance the nanofluid’s temperature, whereas the Prandtl number and the unsteady parameter do not. Variations in temperature and velocity slip are found to reduce entropy generation. When the magnetic field interaction increased by 0.2, the local Nusselt number decreased by 0.1%, whereas the local skin friction rose by 6%. However, both the local Nusselt number and skin friction rose by 0.3% when the curvature parameter increased by 0.2. The findings demonstrate that the flow of nanofluid can be used to transfer heat from solar, which has practical applications in cooking, water heating, and electricity generation. Therefore, the global demand for energy can be partly met by harnessing solar energy effectively.