Simulation of Laminar Natural Convection of Square Enclosure with Partially Heated Adjacent Vertical and Horizontal Walls

Abstract

The present study represents investigation of the laminar natural convection phenomena in an enclosed spaces. Realization of this subject has been done through different Raleigh numbers and aspect ratios, which have to make better understanding and configuration temperature, stream lines and vorticity fields in enclosures. The real physical model of the enclosure, which represents two-dimensional square object with partially heated adjacent vertical and horizontal walls and adiabatic remainig horizontal walls. Physical model represents base for mathematical model which defines valid parameters for temperature flow regime. The two dimensional differential conservation equations of mass, momentum and energy are solved by a finite difference method. Air was chosen as a working fluid (Pr=0.7), for Rayleigh number varying from 103 to 107. The changes in temperature and flow fields (stream functions) with increase in Rayleigh number are investigated for different (Ar). The isothermal cold sections adjacent to the vertical heat source assist the development of secondary circulation cells, that depend upon both Rayleigh number and (Ar). With partial heating and cooling sections on one wall, the flow is characterized by boundary layers lining these sections with separate circulation cells. It is found that Nusselt number is an increasing function of Rayleigh number. For vertical heat source Nu increases with decreasing (Ar), for horizontal heat source Nu increases with increasing (Ar). Results confirmed by previous experiments.