Trends of mathematical modeling for indoor air research

Since the late 1980s, CFD has been a fast developing tool used in the prediction of room air distribution and contaminant dispersion. This proposed book chapter/paper will give a review of recent developments of the technique used in indoor air flows.Two main approaches are available for the study of airflow and pollutant transport in buildings: experimental investigation and computer simulation. In principle, direct measurements give the most realistic information concerning indoor airflow and pollutant transport. Nevertheless, direct measurements of the distributions are very expensive, time consuming, and under many circumstances, impractical.On the other hand, airflow and pollutant transport can be determined computationally by solving a set of conservation and transport equations describing the flow, energy, and contaminants in the system. Due to the limitations of experimental approach and the increase in performance and affordability of high speed computers, numerical solution of these conservation and transport equations provides a practical option for computing airflow and pollutant distributions in buildings. The approach is known as Computational Fluid Dynamics (CFD) technique.CFD technique is a powerful tool to solve indoor environment problems, such as airflow pattern, distribution of air velocity, temperature, turbulence intensity and contaminant concentrations. Due to limited computer power and capacity available at present, turbulence models have to be used in CFD technique in order to solve flow motion. The use of turbulence models leads to uncertainties in the computed results because the models are not universal. Therefore, it is essential to validate a CFD program by experimental data.A number of commercial software is now available. The basic principles and the required program verification and validation work in support of the accuracy of the CFD simulation results are explained. These are then followed by illustrative examples in the airflow analysis of various indoor applications. Finally, the future trends of CFD applications in indoor atmospheric environment are discussed.