Mixing Ventilation System in a Single-Aisle Aircraft Cabin: measurements and design procedure

Traditionally, air is supplied to the aircraft cabin either by individual nozzles or by supply slots. The air is expected to be fully mixed in the cabin, and the system is considered to be a mixing ventilation system. This paper will provide measurements on the mixing flow in an aircraft cabin and present a design procedure of the system. Finally, a personalised ventilation system will be described, which can be used together with the mixing ventilation system.

The experiments are made in a full-scale, left side mock-up of a single-aisle (Boeing 737) cabin with four seats. The four passengers are simulated by thermal manikins. Velocity, temperature and cross-infection risk are measured. The experiments proved that fully developed turbulent flow will take place in the cabin and that the flow element theory can be used for the design procedure when the air flow rate is above a certain level. It is also proven possible to create an acceptable draught level in the cabin.

Experiments with tracer gas indicated that the contaminant from exhalation of one manikin is fully mixed in the cabin, and the experiment with personalised ventilation did not show much improvement in this situation.