Study on three-dimensional natural convection heat transfer in a house with two heating surfaces

Abstract

In order to explore the heat transfer properties of natural convection in the cavity, this article uses the three-dimensional CFD inverse method and the temperature measurement points based on the experimental results. In addition, different flow modes and mesh divisions are used. For the applicability of different turbulence models, the least squares method is then used to calculate Q value of the heat source in the cavity and compare that with the experimental measurement results and consistent with the overall trend. Finally, the temperature distribution diagram and velocity streamline diagram of the simulation results are provided to visualize the flow field and analyze its heat transfer characteristics. The results show that the flow pattern and the number of grid points have a great influence on the results. In terms of experiments, with the change of the cavity size and the influence of the opening, the air flow will be different. To achieve the effect of enhancing natural convection, due to the inflow of a large amount of cold air, although the overall temperature of the cavity is greatly reduced, the upper cold wall is surrounded by cold air, which reduces the heat transfer coefficient. In order to verify the reliability and usability of the results of the inverse algorithm in this article, the obtained results of heat transfer coefficient and heat dissipation are compared with previous results or empirical formulas in other related literature. When the height drops from h = 0.1 m to h = 0.05 m, the average increase in heat transfer coefficient is 2.79%; while for the height drops from h = 0.05 m to h = 0.02 m, the average increase in heat transfer coefficient is 74.8%. When side fin length is reduced form W₂ = 0.1 m to W₂ = 0.08 m, the average increase in heat transfer coefficient is 14.33%; when side fin length is reduced form W₂ = 0.08 m to W₂ = 0.06 m, the average increase in heat transfer coefficient is 41.28%.