LES OF HUMID AIR NATURAL CONVECTION IN CAVITY WITH CONDUCTING WALLS

Abstract

The differentially heated cubic cavity (DHCC) is a common benchmark for studies in application to natural convection, for instance, in passive cooling and ventilation. This system, consisting of an enclosed cavity with two opposing vertical walls maintained at two different constant temperatures, is sensitive to boundary conditions and exhibits complex flow features resulting in changes to the heat transfer. As these effects have previously only been studied in isolation, in the present study, for the first time, the DHCC has been investigated in the presence of humid air and nonadiabatic passive boundaries simultaneously at Ra = 1.58 × 10<sup>9</sup>. In the benchmark study on the DHCC, the cavity depth exceeds the width and height by a factor of 2, so the flow is nearly two dimensional in the midplane. In the present study, periodic boundary condition has been applied to the passive vertical boundaries of a cubic cavity. The findings suggest the effect of inclusion of gas radiation is more prominent than considering transparent humid air. Heat transfer is affected by vortices in the cavity corners and by conduction at the passive walls. The effects are demonstrated by the temperature changes between different cases and the flow structures.