A simplified system for indoor airflow simulation

This paper proposes a simplified system based on a new air supply opening model and a numerical method of solving the discrete algebraic equations to accelerate and simplify the convergence procedure of predicting air distribution in ventilated rooms. The so-called “N-point air supply opening model” is applied to describe boundary conditions of air terminal devices in computational fluid dynamics calculation. It directly and accurately describes inlet boundary conditions and models inlet mass, momentum and buoyancy flows. The new numerical method is called error pre-treatment method, which solves the algebraic equations first on coarse meshes to pre-treat low-frequency error before solving on finer meshes. It is simpler than multi-grid method and effective for SIMPLE algorithm that is commonly used for indoor airflow simulation. A zero-equation turbulence model is adopted to further simplify the simulation. These models and methods constitute the simplified system of indoor airflow simulation. The airflow in a room ventilated by displacement diffuser, square diffuser, and grille diffuser is calculated by the simplified system, respectively. Comparing calculated results to measured data, it is evident that the simplified methodology can predict indoor airflow quickly with satisfactory results for engineering applications.