Simulations of Ozone Distributions in an Aircraft Cabin Using Computational Fluid

9 10 Ozone is a major pollutant of indoor air. Many studies have demonstrated the adverse health effect of 11 ozone and the byproducts generated as a result of ozone-initiated reactive chemistry in an indoor 12 environment. This study developed a Computational Fluid Dynamics (CFD) model to predict the ozone 13 distribution in an aircraft cabin. The model was used to simulate the distribution of ozone in an aircraft 14 cabin mockup for the following cases: (1) empty cabin; (2) cabin with seats; (3) cabin with soiled T-15 shirts; (4) occupied cabin with simple human geometry; and (5) occupied cabin with detailed human 16 geometry. The agreement was generally good between the CFD results and the available experimental 17 data. The ozone removal rate, deposition velocity, retention ratio, and breathing zone levels were well 18 predicted in those cases. The CFD model predicted breathing zone ozone concentration to be 77-99% of 19 the average cabin ozone concentration depending on the seat location. The ozone concentration at the 20 breathing zone in the cabin environment can better assess the health risk to passengers and can be used to 21 develop strategies for a healthier cabin environment. 22 23 24 25 Nomenclature 26 27 A area of the ozone deposition surface C ozone concentration C ambient , C BZ , C cabin , C inlet , and C outlet ambient, breathing zone, volume averaged cabin, inlet, and outlet ozone concentrations C t cabin ozone concentration at time t C µ constant in the k-ε model (0.09) D o binary diffusion coefficient of ozone in air J s ozone deposition flux at surface k turbulent kinetic energy l mean molecular free path L in turbulence length scale m mass of an individual ozone molecule Q supply airflow rate to the cabin r ozone ozone ratio S c ozone source Sc t turbulent Schmidt number t time T air temperature in Kelvin u  air velocity vector U in air velocity at inlet v d ozone deposition velocity v t transport limited deposition velocity V cabin volume of the air inside the cabin Rai, A.C. and Chen, Q. 2012. " Simulations of ozone distributions in an aircraft cabin using computational fluid dynamics, " Atmospheric Environment, 54, 348-357.