Mixed convection study in a ventilated square cavity using nanofluids

Abstract

This work indicates a numerical study on the laminar heat transfer mixed convection in a square cavity with two openings (an inlet and an outlet) on vertical walls through which nanofluid flows. Two flow directions are examined: i) ascending flow which enters the bottom opening and exits the upper opening; ii) descending flow which enters the upper opening and exits the bottom opening. The ascending flow contributes to buoyancy forces while for the descending flow, the opposite takes place. The intention is to cool a heat source placed at the center of the geometry. The nanofluid has Copper nanoparticles and water as its base-fluid. The velocity and temperature of the entrance flow are known. Some results are experimentally and numerically validated. A mesh independency study is carried out. Some parameters are ranged as follows: i) the Reynolds number from 50 to 500, the nanofluid volume fraction from 0 to 1%, the Grashof number from 103 to 105. It is noteworthy to mention that in some cases, the fluid is stuck inside the cavity which weakens the heat transfer. The nanoparticles increase the heat transfer of 4% for the ascending primary flow inside the cavity.

Keywords

• nanofluids
• mixed convection
• finite element method