LARGE EDDY SIMULATION OF INDOOR AIR STABILITY UNDER VERTICAL JET

In this paper, the three-dimensional LES (large eddy simulation) model is used to study the characteristic of the indoor air stability under vertical-jet conditions, on the basis of the concept of indoor air stability. And this article is aimed at investigating the relationships between the indoor temperature distribution and the indoor air stability as well as those between the proliferation and the migration of indoor air pollutants in depth. Firstly the indoor air stability was divided into three categories: stable, unstable and neutral type, which described the ability of the indoor gas blocks' returning to the original locations after disturbance. And then under the same vertical-jet conditions, the three-dimensional LES model was respectively used to simulate the horizontal and vertical proliferation of the contaminants. Research shows that in the vertical jet the unstable type's horizontal turbulence develops and the pollutants' horizontal proliferation capacity enhances; the horizontal turbulence of the stable type is inhibited so the Pollutants are not easy for horizontal proliferation; the neutral's stability is between the two types mentioned above. The results also show that in the vertical jet if (gamma)(the vertical temperature decline rate) is greater than zero, the horizontal turbulence develops and the proliferation capacity of the pollutants in the horizontal direction enhances with the increase of(gamma); if (gamma) is smaller than zero, the results are just the opposite.