Experimental Optimization Of A Chair-based Personal Air Supply System On Commercial Airplanes

Current commercial airplanes supply air from the ceiling diffuser and extract contaminated air at the floor exhaust. It creates a uniform environment, but cannot cater to individual preference to different air environment from different passengers. More critically, once air quality accidents occur, the current system cannot respond effectively to provide protection In order to solve the above problems, this thesis proposed personal chair-based ventilation system with under-aisle displacement air supply to provide the background airflow. As personal ventilation can be designed with many variations, this thesis is in intent to optimize designs of personal air terminal devices from the experimental perspective.The under-aisle air system supplies conditioned air from the under-aisle perforated panels and the air is exhausted from the ceiling exhaust by the thermal plume. Air supply temperature from the under-aisle supply is cooler than the cabin air, so it can cool down the cabin. However, personal supply air from chair armrests is at about 25℃, which is responsible for outdoor air delivery to the inhalation zone of passengers but does not much cool the inside cabin. This thesis compares the round and rectangular shape of air terminal devices and different air delivery directions (30°,45°and 60°from the horizontal) by air terminal devices. To evaluate the system performance, all the experiments are carried out in a double-aisle aircraft cabin mockup containing 35 passengers in seven rows. The cabin mockup was designed to mimic an economy section of a Boeing 767 airplane, and the 35 simplified thermal manikins hold realistic geometric body profiles. The airflow and temperature distribution are measured by a three-dimensional ultrasonic anemometer. Then the outdoor air delivery is evaluated by measuring the CO2 tracer gas concentration by a portable gas analyzer.The results show that the flow patterns by the rectangular and round air terminal devices are similar. As the round air terminals supply less air to the cabin, the temperature in front of the passenger is 0.2-0.4℃higher than that by using the rectangular terminals. If the air is supplied at 30°from the horizontal, both thermal comfort and cabin air quality in the breathing zone can't be guaranteed. At supply angles of 45°and 60°from the horizontal, respectively, it shows the systems create acceptable conditions in terms of thermal comfort and air quality. Especially at 60°, more outdoor air is able to reach the breathing zone.