Experimental Study of Aerosol Dispersion in a Single-Aisle Aircraft with Cabin Displacement Ventilation

Novel ventilation systems for aircraft cabins have attracted the attention of scientists and aircraft manufacturers over the last years due to their potential in terms of energy saving and generating a higher level of thermal comfort. Since the coronavirus pandemic the spread of aerosol particles in cabins has become another important criterion. Recent studies based on computational fluid dynamics simulations highlight the advantages of cabin displacement ventilation (CDV): reduced spreading of aerosol particles in the cabin and faster as well as enhanced particle removal. The aim of the present study is to experimentally determine the aerosol dispersion of state-of-the-art mixing ventilation (MV) -- currently installed in almost all commercial aircraft - and of CDV in the Do 728 test facility of the German Aerospace Center in Göttingen. Both concepts were analyzed in terms of various airflow rates. Further, the location of the index passenger was varied in spanwise and longitudinal direction to allow for a detailed analysis and to improve the fundamental knowledge on the parameters determining the aerosol dispersion. Overall, the results of the present study expand the knowledge regarding the influence of passenger cabin ventilation on the spread of aerosol particles. The main result is a wider distribution under mixed ventilation conditions as well as higher concentrations due to forced convection, while cabin displacement ventilation shows a much better removal of the aerosol particles. Further, the mean and maximum aerosol concentrations are lower for CDV compared to MV conditions. In case of MV, the spread of particle is strongly influenced by the source position, both longitudinally and in the cross-section direction.