射流速度、温度及浓度边界层厚度的研究

Study on Thickness of Velocity, Temperature and Pollutants Concentration Boundary Layers of Jet

通风空调的送风方式一般为射流,要满足室内不同的控制要求,需研究射流速度、温度和浓度边界层。本文讨论了影响层流和紊流射流边界层发展的因素,分析了层流和紊流扩散系数。通过理论分析和CFD模拟得出以下结论:射流边界层的厚度与扩散系数的大小成正比。当Pr≈Prt、Sc≈Sct、Le≈Let时,紊流射流边界层的分布规律可以近似用层流射流边界层的分布规律来表达。当室内污染物为氨气时,紊流射流浓度边界层最厚;当室内污染物为甲醛时,紊流射流温度边界层最厚。

Jet flow is the usual air ventilation. In order to meet the different control requirements, the study of the velocity, temperature and pollutants concentration boundary layer of jet are needed. The factors that affect the laminar and turbulent boundary layer of＇the jet, laminar and turbulent diffusion coefficient were discussed in this article. Through theoretical analysis and CFD simulation, these results were brought out： the thickness of the jet boundary layer is proportional to the diffusion coefficient. When Pr = Prt, Sc ^- Sct, Le ~ Let, the distribution of the turbulent boundary layer of the jet can be expressed by the laminar jet. Pollutants concentration boundary layer is the thickest when the indoor pollutant is ammonia, and temperature boundary layer is the thickest when the indoor pollutant is formaldehyde.