Numerical Simulation of Natural Convection in a Rhombic Enclosure with Heated Sidewall Coated with Metal Foam

Abstract

A natural convection heat transfer inside rhombic square cavity partially filled with porous material have been numerically investigated. A constant heat flux has been applied to the left wall with a right wall kept in constant cold temperature while thermally insulated the top and bottom walls. Finite volume technique with Simple algorithm have been used to simulate the governing equations of fluid flow and heat transfer coupled with Darcy-Brinkman model to simulate the flow of the air inside the main cavity and the open cells of the porous media. Three factors were chosen to study their effects on the natural air velocity and the mechanism of the free convection inside the enclosure. The inclined angle of the sidewall of the rhombic (q = 90o, 80o and 70o), the thickness of the metal foam (t = 5 cm, 10 cm, and 15 cm) and the amount of heat flux (q = 150 to 600 w/m2). Copper metal foam with 0.9 porosity was chosen as porous media with open cell filled by air (Prandtl number =0.7) and 10 as pore density. The results showed that using a layer of porous metal foam with open cells will increase the heat transfer rate. It was 41.3% enhancement when use 5 cm of porous media and 68% for 15 cm. Acute inclined angle will decrease local Nusselt number and led to form vorticities. Furthermore, high heat flux increased the average Nusselt number and improved the heat transfer rate.

Keywords

• Finite volume method
• Metal foam
• Natural convection
• Rhombic cavity
• Heated sidewall