Electro-enhanced natural convection analysis for an Al <sub>2</sub> O <sub>3</sub> -water-filled enclosure by considering the effect of thermal radiation
Seyyed Masoud Seyyedi, M. Hashemi‐Tilehnoee, Elena Palomo del Barrio, A.S. Dogonchi, Seyyed Mostafa Ghadami, Mohsen Sharifpur
Abstract
One of the most crucial topics in the thermal sciences is the analysis of how an external electric field affects the natural convection flow. In this study, the heat transfer of electro-hydrodynamic natural convection in an enclosure with a wavy hot wall is numerically studied. Al2O3-water nanofluid is considered as the working fluid, and furthermore, the effect of thermal radiation on the characteristics of fluid flow is simulated. Non-dimensional forms of governing equations are numerically solved using control volume finite element method. The effects of operational parameters such as Rayleigh number, nanoparticles volume-fraction, Lorentz force number, Eckert number, charge diffusivity number, and electric field number on the maximum absolute value of stream function and the average Nusselt number are investigated. Two new parameters are defined to evaluate the contribution of the electrical field and radiation effects on the fluid flow. The results show that Nuave ascends 7.95% when ϕ increases from 0 to 0.05 at Ra=105. Also, the values of |Ψmax| and Nuave increase 27.6% and 37.2%, respectively, when λ goes up from 0 to 0.5 at Rd=1.0. The values of |Ψmax| and Nuave decrease 48.7% and 27.1%, respectively, with decreasing the amplitude parameter (an) from 0.1 to 0.3 at Ra=105.