Heat transfer intensification of NEPCM-water suspension filled heat sink cavity with notches cooling tubes by applying the electric field

Abstract

The effects of an electric field on heat transfer, free convection, and entropy generation of nano-encapsulated phase change material (NEPCM) dissolved in water in a complex inclined chamber are studied. The enclosure consists of a rectangular cavity heated from below and the remaining walls are considered adiabatic. The fluid is cooled by eight cooling tubes, each with four notches. The effects of the electric field, inclination angle (ζ = 45° and ζ = 90°), and Rayleigh number (Ra = 103, 104, and 105) in equal concentration of NEPCM (ϕ = 2 %) are studied using ANSYS Fluent CFD code. The dimensionless form of fluid governing equations, electric potential equation, electric charge density equation, and entropy generation equation are used to set the primitive parameters. Grid verification and validation tests are performed to ensure the reliability of the solution. Calculations show that with increasing Ra, the average Nusselt number (Nuave) decreases from ζ = 45° to 90°, but when an electric field is applied, the results are reversed. As the Rayleigh number increases in conjunction with the electric field, the buoyancy effect becomes more pronounced. Furthermore, owing to its high heat transfer potential and lowest irreversibility, the straight cavity (ζ = 90°) is desirable at Ra = 105.