Simplified method for indoor airflow simulation.

At present, numerical simulation of room airflows is mainly conducted by either the Computational-Fluid-Dynamics (CFD) method or various zonal/network models. The CFD approach needs a large capacity of computer and a skillful expert. The results obtained with zonal/network models have great uncertainties. This paper proposes a new simplified method to simulate three-dimensional distributions of air velocity, temperature, and contan-finant concentrations in rooms. The method assumes turbulent viscosity to be a function of length-scale and local mean velocity. The new model has been used to predict natural convection, forced convection, mixed convection, and displacement ventilation in a room. The results agree reasonably with experimental data and the CF1) computations. The simplified method uses much less computer memory and the computing speed is at least 10 times faster, compared with the CFD method. The grid number can often be reduced so that the computing time needed for a three-dimensional case can be a few minutes in a PC.