The Bureau of Transportation Statistics  indicates that the number of passengers using commercial aircrafts has doubled over the last two decades reaching to approximately 813 million passengers in 2012. Biological and chemical incidents have been detected on flights such as SARS (Severe Acute Respiratory Syndrome) and H1N1 (swine flu). Chemical incidents that were reported can be related to smoke and fumes detected inside passengers’ cabins. The smoke and fumes are thought to be a result of oil pyrolysis inside the jet propulsion engines of the aircraft that can leak into the passengers’ fresh air supply duct system. Such odors, fumes, viruses, and bacteria can result in serious health hazards. Consequently, considerable research have been and continues to be conducted to understand fluid dynamics characteristics of airborne gaseous and particulate transport and their distribution inside passenger cabins to develop means for detecting, controlling, and removing such contaminants from cabins.
The objective of the present study was to understand the airflow distribution and gaseous transport phenomena inside a mockup aircraft cabin. A testing chamber that mimics a Boeing 767 passenger cabin was used for this study. The mockup cabin includes 11 rows in the longitudinal direction with each row consisting of 7 seats. The mockup cabin seats, the air supply duct, and linear diffusers are original parts from a salvaged Boeing 767 aircraft. Each seat in the cabin is occupied by an inflatable manikin which was instrumented with a 10 m long wire heater element to generate approximately 100 Watts of distributing heat, representing heat load from a sedentary human being.
Smoke visualizing technique was used to visualize the airflow inside the cabin. Tracer gas, composed mainly of carbon-dioxide, was then used to track the airflow distribution inside the cabin. Carbon dioxide was released in several locations inside the cabin and was then sampled at various locations throughout the mockup cabin. Results showed that the flow inside the cabin was chaotic and difficult to quantify. However, using visualized smoke in conjunction with quantitative results from sampling the tracer gas showed that there exist several swirling and circulations inside the cabin. Two clockwise, large size, circulations dominated over the front and middle sections of the cabin. Each circulation controlled the flow over approximately four consecutive rows in the longitudinal direction and over the entire cross section. The results from the aft section of the cabin were less definitive. The west-back side was controlled by a clockwise directed circulation having the same longitudinal strength as in the front and middle sections, but dominated over half the width of the cabin cross section. On the other side, the east-back region was rather controlled by smaller circulations flowing in the counter clockwise direction.