Buoyancy Driven Turbulent Heat Transfer Characteristics in Enclosure Filled with Phase Change Materials

Abstract

The exponentially growing computing capabilities of electronic circuits require effective and efficient heat sink designs to control the temperature inside the system. To achieve the desired temperature for efficient working of electronic devices, phase change materials are widely used. In the present study we discuss the complex flow physics of a phase change material filled in a cubical enclosure in the turbulent flow regime with a local heater mounted on the enclosure bottom wall. The thermal properties of local heat source are that of silicon at a working temperature of 330 K. The walls of the enclosure other than the heat source are considered as adiabatic. The turbulent natural convection flow is modeled by the computational fluid dynamics (CFD) approach using Reynolds averaged Navier-stokes equation (RANS) with Lambremhorst k-ε turbulence model. A finite difference method is used to discretize the governing equations and an in-house CFD code is developed for simulating the turbulent characteristics. The flow physics of three different phase change materials (n-Octadecane, PEG900, Paraffin (RT60)) has been analyzed with Groshof number being fixed for all three phase change materials. The transient flow characteristics are investigated by plotting the stream function, velocity and temperature contours of the phase change materials..