Numerical analysis of double-diffusive natural convective flow of Ostwald-de Waele fluid in an irregular enclosure with a circular obstacle

Abstract

PurposeThe current study aims to enhance the double diffusive natural convection in an Ostwald-de Waele fluid filled in a hexagonal enclosures using non-uniform magnetic field embedded with circular obstacle. The upper wall has maximum temperature Th∗ and concentration (Ch∗) whereas the lower wall is kept at minimum temperature Tc∗ and concentration Cc∗. The parameters that play a significant role in the heat and mass transfer are evaluated, including Hartmann number, power law index, Rayleigh number and buoyancy ratio. Design/Methodology/approachIn two-dimensions, the governing formulation is written as a set of balancing equations for velocities, pressures, energies and concentrations. The nonlinear governing PDEs are solved using numerical approach based on Finite Element Method (FEM). The discretization is performed using the stable finite element pair ℘2/℘1. Code validation and results are ensured by conducting a grid convergence and comparison test respectively. FindingsThe influence of flow on velocity, isotherms and iso-concentration field is examined by analyzing a broad variety of variables such as power-law index 0.7≤n≤1.2, Hartmann number 0≤Ha≤50, Rayleigh number 104≤Ra≤106, inclination angle 0°≤γ≤90° and buoyancy ratio -2≤N≤2. The findings are displayed graphically, including the flow, temperature and concentration fields. Heat and mass transfer rates are maximum for shear thinning fluids while for shear thickening fluids it reduces, whereas it is maximum for concentration dominated assistant flow and minimum for concentration dominant counter flow. ApplicationThe novel aspects of the research include its thorough examination of solar thermal power conversion and its inventive energy deficiency devices and a wide range of electrical design applications.