In-Flight Infrared Thermography for Studies of Aircraft Cabin Ventilation

To improve the convenience of aircraft cabins, Cabin Displacement Ventilation (CDV) was investigated during flight tests in an Airbus A320 with an automatically rotatable infrared camera. For this purpose a programmable, step motor driven infrared camera setup was developed, allowing for time resolved acquisition of the temperatures on the interior cabin surfaces during the whole flights. From the temporal development of the surface temperatures the cooling and heating performance of pure CDV as well as a hybrid system (HV), where 30 % of the fresh air was supplied through the original lateral outlets, was analyzed and characterized. Static measurements reveal a characteristic, yet homogeneous temperature distribution in the cabin for both scenarios, pinpointing to a homogeneous cooling of the heat loads in the whole cabin. In order to study the performance of CDV and HV, dedicated “pull-up” and “pull-down” scenarios, those are abrupt changes of the inflow temperature with the objective to study the heating and cooling dynamics, were conducted during the flight tests. Analysis of time resolved measurements discloses that the cooling performance of the cabin is limited by thermal diffusion of heat inside of the interior cabin materials.