Rotating Al_2O_3-H_2O nanofluid flow and heat transfer with internal heating, velocity slip and different shapes of nanoparticles

摘要

Purpose - This research numerically investigates the steady laminar 3D forced convective flow and heat transfer of a rotating Al_2O_3/water nanofluid past a linearly stretching sheet with the help of a novel two-phase analysis method by considering different nanoparticle shapes as well as velocity slip boundary condition plus internal heating. Design/methodology/approach - The authors' novel two-phase analysis method implements the Jang and Choi model for the effective thermal conductivity and incorporates it with Tiwari-Das mathematical model. Besides, the shape factors of the nanoparticles have also taken into account using the Timofeeva model for effective dynamic viscosity. The Prandtl number of the base fluid is kept constant at 6.2 and the temperature of the nanoparticles as well as the base fluid molecules is assumed to be 300 K. In short, after using the similarity transformation method, the obtained dimensionless nonlinear ODEs are numerically solved using the bvp4c built-in function from MATLAB. The governing parameters are solid volume concentration, rotation parameter, velocity slip parameter, heat generation or absorption parameter and Prandtl number of the base fluid. Findings - It is argued that when the cylindrical shape for alumina is chosen, the maximum values for skin friction coefficients and local Nusselt number have been obtained among the other shapes. Further, the velocity slip enhancement in this problem will lead to a drastic reduction in the foregoing quantities of engineering interest. Originality/value - To the best of the authors' knowledge, this research is a novel attitude to two-phase nanofluid model.