Convegni ATI - Accesso riservato soci CTI

Autore: A. Andreozzi, B. Buonomo, O. Manca

Collana: CA - 61 - Perugia 2006

Note:
In this paper a numerical transient analysis of natural convection in air in a vertical channel asymmetrically heated at uniform is carried out. One channel wall is heated at uniform heat flux, whereas the other is adiabatic. The transient problem is twodimensional and laminar. Constant and variable property models are considered. For both models numerical solution is carried out employing the commercial CFD code Fluent. The computational domain is made up of the physical configuration and two reservoirs, placed downstream and upstream the channel. Results are obtained for Rayleigh number between 102 and 106 and they are presented in terms of wall temperature profiles as a function of time, stream function and temperature fields. The simulation allows to detect the fluid motion structures inside and outside the channel. Wall temperature profiles as a function of time show an overshoot for all considered cases and for Ra≥105 an undershoot is observed. For the highest Ra value, 106, a cold inflow inside the channel is observed. Comparison between constant and variable property models in terms of wall temperatures shows that the differences between the two models increase as the Rayleigh number increases.