Numerical analysis and optimization of different ventilation systems for commercial aircraft cabins

The ventilation systems in commercial aircraft cabins are important for providing a healthy and comfortable environment for the passengers and crew. The high density and close proximity of passengers in the modern aircraft cabin exposes them to the risk of contracting airborne diseases such as flu, severe acute respiratory syndrome (SARS), and tuberculosis. Current aircraft personalized ventilation (PV) systems still cannot ensure a constant circulation of fresh humidified air around each passenger´s breathing zone to shield them from airborne contaminants. It is proposed to investigate the use of PV systems in aircraft cabins using computational fluid dynamics (CFD) techniques. This would lead to better understanding and an improved microclimate around the breathing zone of each passenger. A comprehensive analysis framework based on the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) thermal comfort assessment models has been developed. The components of the framework consists of the age of air, predicted mean vote (PMV), predicted percentile dissatisfied (PPD), draught risk (PD), a contaminant aerosol transport model and a humidity model. The objective of this paper is to compare and analyze the simulated cabin environment with mixing, under-floor displacement, and personalized ventilation systems to improve air quality in the aircraft cabin of the economy section of a Boeing 767 airplane during cruise and to reach the optimum design to protect passengers fromair pollution inside the cabin. CFD modelling techniques using the ANSYS FLUENT 15.0 package solved the continuity, momentum, energy, and species transport equations in addition to k-e model equations for turbulence closure. The SIMPLEC algorithm was used for the pressure-velocity coupling and a second order upwind scheme was used for discretization of the governing equations. Mesh sizes used in the present work exceeded 6,000,000 mesh volumes in one case.