PIV experimental study of the large-scale dynamic airflow structures in an aircraft cabin: Swing and oscillation

Publication date: 15 November 2017
Source:Building and Environment, Volume 125
Author(s): Jiayu Li, Junjie Liu, Congcong Wang, Mark Wesseling, Dirk Müller
The dynamic behaviors of airflows, which are common in aircraft cabins with mixing ventilations, significantly influence the thermal sensation of passengers and contaminant transmissions. In this paper, to analyze the large-scale dynamic characteristics in aircraft cabins, a series of long-term large-scale particle image velocimetry (PIV) measurements were performed in an aircraft cabin mockup to provide necessary basic data. Two typical airflow fields, jet zones characterized as large-scale circulations and collision zones featured as interactions of two lateral jets, were selected as the research objects of the dynamic behaviors in the cabin. In collision zones, the temporal characteristics of the swing motions were presented via proper orthogonal decomposition (POD) method, and the swing periods were 25.2 s–29.8 s and 13.0 s–19.8 s under isothermal and cooling conditions, respectively. By analyzing the occurrence probability of swings, the swing-induced contaminant transmission regularity was presented. In jet zones, the dynamic behavior of large-scale circulation was revealed by identifying the circulation center of each instantaneous flow field. However, the center oscillated in a small range near the breath zone of the passenger seating in the middle of one side, and the plumes under cooling conditions further reduced the range, which explained the lock-up phenomenon founded in contaminant transmission studies in the cabin. Finally, several vortex identification methods with raw and reconstructed instantaneous airflow fields were compared, and their practicalities were discussed.