The Simulation Research On Hybrid Ventilation In The Architecture

With the development of society, people's requirements to comfort in modern buildings are higher and their environmental consciousness are increased at the same time , so the conventional ventilation ways including nature ventilation and mechanical ventilation has been oppugned. As a completely new mode, hybrid ventilation system combines the merits of natural and mechanical driving forces. This system can satisfy air quality indoor by using less energy. Therefore, it's very important to do research on the system.The flow pattern in this system is turbulence, which is nonlinear fluid dynamics anomalously in space and in time. The physical quantities expressing turbulence are correlative and fluctuant. High-order correlated partial differential equation will appear when fluctuation is modified. And the new unknown quantity will come forth. Therefore, the turbulence equations can't obtain the precise solution. The traditional research methods — model testing method and the empirical formula method, have the demerit of cost high, and speed slow, applicable range small and data unreliable. On the contrary, CFD is favor because cost low, speed quick, data abundance. With the development of computer technology and simulation, CFD has been widely applied in solving actual project problem. It is main research method to apply the CFD technology to carry on the numerical simulation for hybrid ventilation system.A commercial CFD software — FLUENT is presented for the numerical simulation of hybrid ventilation systems in this thesis, which has advanced preprocessing and postprocessing. Consequently, researchers can extricate themselves from the fussy work of establishing numerical algorithm and programming, and spend more time on quest for the essence of the problem.A numerical model of hybrid ventilation system is established in this thesis including two parts —tunnel air-cooling and displacement ventilation. The flow pattern in this system is turbulence, which is nonlinear fluid dynamics anomalously in space and in time. A k-ε two-equations model based on Reynolds-averaged Navier-stokes equations with modification of buoyant effect is used to simulate the turbulence. Wall function method is also used to process boundary conditions near the wall. The results are calculated by iteration method with the modification of pressure.Through numerical simulation, the distributing characteristics of velocity field and temperature field of the system are obtained. The simulation results show that the...