Propagation of Localized, Unsteady Heat Loads in Aircraft Cabin Air Flows

Abstract

The propagation of heat, released from a local source in aircraft cabin air flow was studied experimentally using two different ventilation systems. Besides the state-of-the-art mixing ventilation system, a ceiling based cabin displacement ventilation system was employed. As test environment, we used the Do 728 test facility of the German Aerospace Center in Göttingen. We measured the response of the cabin temperatures to the released heat by evaluating the cross-correlation function between the local temperatures and the normalized surface temperature of the heat source, which was heated periodically. Three different nominal heating powers of the heat source, ranging from 100 W to 400 W, were considered. By analyzing the data, the gradual change of the temperature from a passive to an active scalar could be observed. While the two ventilation systems perform similar at the lower source powers, the distinguished air guiding principles of the momentum- driven MV and the buoyancy-driven CCDV imply different propagation paths at higher power settings of the heat source. For the first time, the spatial spreading of locally released heat in mixing ventilation and ceiling based displacement ventilation was determined in an aircraft cabin.