Análise numérica de escoamento por convecção natural limitada por paredes

Abstract

In our research, we investigated natural convection in a cubic cavity, a fundamental problem in heat transfer and fluid dynamics. The main objective is to understand the behavior of airflow dynamics across different regimes, utilizing Ansys software for numerical simulations. The methodology employed consists of simulating the cavity, bounded by walls at distinct temperatures, using the Boussinesq approximation to model fluid motion. In a preliminary analysis, we varied parameters to reach specific Rayleigh numbers (Ra) of 104, 106 and 109 and refined the simulation mesh (30x30x30, 40x40x40, and 50x50x50 cells) to ensure result accuracy. Our findings indicate a clear regime transition with increasing Ra. At Ra=10', the flow is laminar and stable. For Ra=10°, we observe the emergence of vortices and more complex flow patterns, indicating a significant increase in convection intensity. At Ra=10°, the flow becomes highly turbulent and chaotic, completely dominating heat transfer over conduction. These results confirm expected physical behavior and demonstrate the numerical model's capability to capture complex phenomena. This study is relevant for practical applications such as the design of electronic cooling systems and the optimization of solar collectors, where a precise understanding of natural convection is crucial for efficient and safe design.