Statistical Analysis Approach of Single-sided Ventilation Based on Particle Track Technique Using Large Eddy Simulation

¹ Department of Architectural Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan
² Department of Building Engineering, Energy Systems and Sustainability Science, University of Gävle, Gävle, Sweden

^* Corresponding author: jiang_zitao@arch.eng.osaka-u.ac.jp

Abstract

The main objective of this study is to investigate the airflow characteristics in single-sided ventilation. A CFD method of large eddy simulation (LES) using particle track technique was conducted in this study, and the simulation results are validated by experiment results. The mostly used ventilation efficiency indicators of natural ventilation are Air Flow Rate (AFR) and Purging Flow Rate (PFR). AFR is the volumetric airflow exchange rate through the openings and PFR is the effective airflow rate that removes indoor air pollutants. The ventilation efficiency (ε_ν) of natural ventilation, which is defined as the ratio of PFR and AFR, is not well investigated in previous research, therefore, this study discusses the case of the ε_ν of single-sided ventilation and tries to explain the distinction between AFR and PFR by statistical analysis approach based on particle movements. Particles are emitted from the opening and the particles’ movements are tracked by tracing their locations at different time steps. The residence time measures the time between the time that particles enter the room and the time that particles leave the room, and indoor travel distance indicates the sum of the displacement when the particle travels in the room. The Probability Density Function (PDF) of the residence time and indoor travel distance is used to depict airflow characteristics of the ventilation path of single-sided ventilation. The analysis method of study might be another useful approach to studying natural ventilation in detail.