Abstract
One of the most interested and essential subjective in mechanical science is natural convection analysis in a cavity. Thus, natural convective flow and entropy generation are scrutinized numerically subjected to magnetic field effect in a semi-annulus enclosure which known as the effect of magneto-hydrodynamic (MHD). Firstly, the governing expressions are rewritten in non-dimensional form utilizing the definition of dimensionless parameters, stream function, and vorticity. Secondly, the entropy generation equation is expressed in non-dimensional form. Then governing non-dimensional expressions are computed by control finite element method (CVFEM). Furthermore, the governing expressions are computed employing finite volume method (FVM) utilizing ANSYS Fluent CFD code. A novel criterion for determination of thermal characteristics of cavity based on thermodynamics second relation is introduced that is called ecological coefficient of performance (ECOP). Flow and heat transport features in addition to entropy generation number are examined for distinct values of the Rayleigh number (Ra = 103,104,105), the orientation of the magnetic field (β = 0°,15°,30°,45°,60°,75°,90°), and Hartmann number (Ha = 0,5,10,15,20). For validation, the entropy generation number and average Nusselt number are compared with those available in literature and excellent agreement is observed. Isotherms and streamlines are calculated using CVFEM and FVM. Some correlations for entropy generation number are proposed. The results show that for constant Rayleigh number, the entropy generation number decays with increasing Hartmann number. Also, for each Hartmann number, there is an optimum inclination angle of magnetic field that gives a minimum for entropy generation number and a maximum for ECOP at each Rayleigh number.
Published Version
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