CFD Simulation On Nonisotheramal Ceiling Jet

Understanding room air distribution is essential to the design of a ventilation system and air quality conditions. Air velocities in occupied zones of a room directly affect the thermal comfort of the occupants. The movement of air within a room can affects the release rate of heat and contaminants from various sources. Air movement also determinants how the heat and contaminants are distributed and thus affects the air quality in door. Proper air distribution can reduce the ventilation rate necessary for removing air contaminants and thus reduce building energy consumption. There are kinds of indoor airflow patterns, but the most of is confined jet. Wall jet as one of the airflow patterns which has many of advantages such as slow velocity decay, large effect space, uniform heating transaction, and the occupied zones at the backflow zones and the simple pipes plan, convenient installation, low cost and convenient maintenance and manage, so it is applied widely in many conditions for many years, and become a kind of traditional pattern of air supply. So study on the coanda effect of the jet is very useful and important.The realizable k-ε model is a relatively recent development and differs from the standard k-ε model in two important ways: (1) The realizable k-ε model contains a new formulation for the turbulent viscosity. (2) A new transport equation for the dissipation rate which has been derived from an exact equation for the transport of the mean-square vorticity fluctuation. An immediate benefit of the realizable k-ε model is that it more accurately predicts the spreading rate of both planar and round jets. It is also likely to provide superior performance for flows involving rotation, boundary layers under strong adverse pressure gradients, separation, and recirculation. The studies have shown that the realizable k-ε model provides the best performance of all the k-ε model versions for several validations of separated flows and flows with complex secondary flow features. In this study we chose the realizable k-ε model for the study of the nonisotheramal horizontal wall jet, the physical model and numerical model were established for nonisotheramal horizontal wall jet in air-conditioning room, and used a proper numerical method compared with the experiment method. Some physical characteristic index signs acquired of nonisotheramal horizontal wall jet. The objective of this paper was to investigate the source, the supply air velocity, the location of the outlet and the girder which can affect the room jet characteristics, all these varying factors were studied computationally and discussed.