Transport and distribution characteristics of contaminants in commercial airliner cabins

Rapid and advanced development of space undertakings and aeronautics result in the blooming popularity of air travel nowadays. While the demand for air travel is continuously increasing, the safety and health concerns with respect to the cabin environment also continue to grow as a result of those cabin air quality-related incidents. It is found that multifarious types of contaminants, such as those particulate types (e.g. pathogen-bearing droplets, secondary organic aerosols) and gaseous types (i.e. ozone production), are the key determinants and causes of those events.  To date, the air quality in the passenger cabin has been widely studied due to its uniqueness in operational and environmental conditions (i.e. high dense occupancy, low humidity, etc).  While the pivotal understanding of the passenger cabin environment is persistently improving, the importance of the cockpit environment with respect to the occupant's health, safety and comfort have yet to be emphasised. The cockpit environment merits further investigation as the performance of the pilots is directly related to flight operation and flight safety. Therefore, the major purpose of this project is to deepen the understanding of the control cabin environment by assessing the transport and distribution of the air pollutant in the cockpit and the corresponding pilot’s micro-environment. Computational Fluid Dynamics (CFD) has been proven to be a cost-effective tool to solve complex modern problems involving multi-scale and multi-coupling mechanisms. This approach was used in this project to provide a holistic analysis of the cockpit environment in terms of ventilation performance, pilot’s thermal comfort and contaminant transport and inhalation characteristics. The main body of the thesis was composed of eight chapters. First two chapters provide an overview of the research background, motivation and the major gaps found in the existing literature, followed by a detailed description of the research methodology in Chapter 3. The main research contributions could be found from Chapter 4 to Chapter 7. Chapter 4 evaluated the ventilation performance in terms of air mixing and contaminant removal, which aimed to provide a fundamental understanding of the airflow distribution and contaminant transport in the control cabin environment. In chapter 5, the major focus of the cockpit environment would be further narrowed down to pilots’ surrounding environments (i.e. microenvironment). The pilots' thermal sensations and satisfaction with each body segment were carefully evaluated and contaminant distribution characteristics within the pilots’ breathing region were also analysed. Chapter 6 further illustrated the effect of various human respiratory behaviour (i.e. coughing and speaking) on the human micro-environment by predicting and investigating the transient variation of respiratory jet flow and spatiotemporal transport characteristics of the respiratory-related contaminants. In Chapter 7, it enlightened a new pathway for conducting a comprehensive analysis of air quality within the cockpit, for the first time, integrating a full-scale cockpit model and detailed manikins with anatomical features of nasal cavity models, to investigate gaseous contaminant transport, distribution and inhalation characteristics. All the aforementioned contributions are concluded and highlighted in Chapter 8, followed by a list of all published publications during the PhD candidature period.