Influence of air supply form on contaminat diffusion of bleed air in aircraft cabin

The co-simulation method was adopted to realize the adjustment of aircraft environmental control system to cabin environment. The closed-loop simulation model of aircraft environmental control system to cabin environment was established. The effects of different air supply forms on the propagation of airborne contaminant in the passenger breathing area were studied under considering recirculating air. Taking B737-200 cabin model as the research object, the distributions of contaminant in the breathing area under the ceiling, sidewall and mixed air supply modes were analyzed under the same air supply quantity and different proportions of recycled air when air contamination event occurs. Research result shows that in the state that the contaminant enter the cabin, the concentrations of contaminant in different air supply forms and the proportions of recycled air are different at different positions, and the concentration of contaminant in ceiling air supply form is higher. When the proportion of recycled air increases by 20%, the concentrations of contaminant in the forms of mixed air supply, sidewall air supply and ceiling air supply decrease by about 18.9%, 20.6% and 15.6%, respectively, and the contaminant concentration decreases most under the form of sidewall air supply. In the contaminant removal stage, compared with the mixed air supply and ceiling air supply, the contaminant removal efficiency of sidewall air supply increases by about 42.6% and 38.7%, respectively. When using the mixed air supply or ceiling air supply, the contaminant removal efficiency increases significantly with the increase of the proportion of recycled air. When the proportion of recycled air increases by 20%, the contaminant removal efficiencies of mixed air supply and ceiling air supply increase by about 10.7% and 7.7%, respectively. With the increase of the proportion of recycled air in the form of sidewall air supply, the contaminant removal efficiency is not significantly improved. At a higher proportion of recycled air, the best contaminant remove efficiency can still be maintained, which can realize the dual optimization of pollutant removal and energy saving. Therefore, the use of sidewall air supply and high recycled air ratio can minimize the harm of contaminant without changing the air supply volume. 1 tab, 18 figs, 31 refs. © 2019, Editorial Department of Journal of Traffic and Transportation Engineering. All right reserved.