An innovative mass-based model of aqueous zinc oxide-gold hybrid nanofluid for von Karman's swirling flow

In this research, we have investigated analytically the incompressible laminar steady three-dimensional boundary layer flow of an aqueous ZnO-Au hybrid nanofluid over an impermeable rotating disk with the constant radial stretching rate. The novel attitude to single-phase hybrid nanofluid model corresponds to considering nanoparticles mass as well as base fluid mass to computing the solid equivalent volume fraction, the solid equivalent density and also the solid equivalent specific heat at constant pressure. Here, other governing parameters are stretching strength parameter (C), shape factor parameter (n) and Prandtl number (Pr). The basic nonlinear governing PDEs are transformed into a set of dimensionless nonlinear ODEs using well-known von Karman similarity transformations, which are then solved numerically using a finite difference code from MATLAB. It is worth mentioning that validation results demonstrate a good agreement with previously published reports. Results indicate that with the increase in stretching strength parameter and second nanoparticle's mass, both dimensionless temperature distribution and thermal boundary layer thickness decrease. Moreover, when 15 g of both first and second nanoparticles is dispersed into 100 g pure water (equivalent with phi = 3.33% as the total nanoparticles volume fraction), the heat transfer rate increases more than 40% in comparison with the regular fluid. Besides, the results demonstrate that the heat transfer rate enhances about 2.18% with nanoparticles of platelet shape (n(1) = n(2) = 5.7) instead of spherical ones. Finally, the present new algorithm sufficiently can be used for analysis flow and heat transfer characteristics of hybrid nanofluids in various problems with great confidence.