On November 2, 2015, China rolled out its first homegrown large passenger aircraft C919 off the production line in Shanghai. The environmental control system of C919 is referred to as the respiratory system of an aircraft. The environment in the cabin exerts an impact on the health and comfort of passengers.
Tianjin University has successfully completed the numerical simulation and optimal design of the cabin environmental control system by designing a specific air distribution program. As a tribute to the program the air in the cabin of the C919 aircraft is twenty percent fresher than regular commercial airliners, while the thermal comfort settings for passengers is increased from seventy percent to ninety percent. These breakthroughs are significant given the absence of such high-end technological developments in China.
Due to the rarefied air and increasing differences in pressure in and outside the cabin at cruising altitudes, the ambient atmosphere and temperature can change to seventy degrees centigrade. Therefore, it is crucial to ensure the availability of the large aircraft’s air distribution system.
After the completion of the aircraft’s overall design, Tianjin University’s task was to establish, a numerical simulation and optimal design of the air distribution system which is the most critical part of the cabin environmental control system. Through scientific analysis, passengers have an access to fresh air and a cozy temperature irrespective of where they are seated.
At Tianjin University’s Cabin Air Environment Simulation Laboratory, a cabin with seven rows of seats were being detected by laser. Human-sized models were seated in a cabin and twinned with heating wires to simulate the body heat from passengers. “Our team repeatedly tested and made the cabin air circulate and refresh with the least ventilation” said Professor Liu Junjie, who is from both the School of Environmental Science and Engineering, and the Cabin Air Environment Simulation Laboratory at Tianjin University. Professor Liu also expressed, that one of the most impressive spots of C919 is the utilization of new types of air distribution system so as to make the air cleaner, fresher and distribute more evenly. With the new design of the air outlets, the air flow was increased and passengers’ discomfort caused by the uneven distribution of cold and hot air was reduced with the simultaneous delivery of air from the top and sides of the luggage racks in the cabin. “The data for Airbus and Boeing mainly reflect the comfortable temperatures of western passengers while this data is based on the comfortable temperatures for Chinese passengers. This will make Chinese passengers travel more comfortably.” Said Professor Liu.
In 2008, Tianjin University invited Professor Chen Qingyan, a scholar of the Chang Jiang Program, to conduct research. A McDonnell Douglas 82 aircraft was bought with RMB tens of millions and established the only experimental platform for cabin environment control system with a whole airplane. This platform has made some initial research and tests for the Boeing Company. In 2009, the lab worked on the numerical simulation and optimal design of the large passenger aircraft C919.
From 2008 till today, about forty people in Chen Qingyan’s research group are from Tianjin University and have led the development of related disciplines and the training of talents, while significantly promoting the scientific cooperation of fields in China. A series of outcomes achieved from the research of cabin air environments of aircrafts have been successfully utilized in domestically-built ARJ21 airliners and the large C919 passenger aircraft.
