Simulation Strategy On The Airflow Characteristics In Aircraft Cabin With Ventilation Systems

Nowadays,more than a quarter of the population in the world travel by plane,so the environment in aircraft cabin has become more and more important.A lot of academic researches show that it is the airflow distribution in aircraft cabin that influences the cabin’s environment and thermal comfort of passengers directly,thus,accurate simulation and analysis of the airflow characteristics in aircraft cabin are significant in predicting and controlling the air quality and contaminant transmission.However,the cabin’s whole size of aircraft cabin is large and ventilation system with small personalized and main vents is very complex,so finding an appropriate and efficient numerical strategy to simulate the coupled and changeable airflow is a crucial way to the study on airflow characteristics in aircraft cabin.Respect to the challenge of grid quality and quantity caused by the high scale ratio problem of numerical simulation to the aircraft cabin of large space with local personalized vents in MD-82,firstly,the κ-ε turbulent model with modified dissipation rate(MDR κ-ε model)suitable for personalized vent’s jet flow with large scale grid was presented and by comparing the results of MDR κ-ε model with standard κ-ε turbulence model,it was verified that MDR κ-ε model can solve the gird matching problem with reduced the grid number by 90% efficiently,and the reasonable mesh scale-ratio in the cabin with vents,which was suitable for MDR κ-ε model,was determined.This model was applied to simulate the airflow in isothermal and air-conditioned single-row cabin,by comparing the simulated results with experimental data,the applicability of MDR κ-ε model in the efficient simulation of cabin’s main flow was verified,and this model can control the cabin’s grid number efficiently without reducing the simulation accuracy.Thus,the efficient simulation strategy of coupling the personalized vent’s jet to cabin’s main flow by using the MDR κ-ε model was proposed.Then,the study on the effect of personalized vents’ different supply flow rates on velocity filed,temperature filed and passengers’ thermal comfort shows that the velocity and temperature around the passenger near aisle had a more uniform distribution,which can provided a more comfortable environment.In addition,with the increasing of personalized vents’ flow rate,the influence on velocity and temperature were enhanced significantly,but the range of influence caused by personalized vents was concentrated in the area near the jet flow of personalized vents without strong radial diffusion.Finally,the simulation strategy was applied to the simulation of airflow in seven-row cabin.With the same air supply condition in each row cabin,the periodicity of main airflow in each row cabin was obtained,and the weak longitudinal flow with a speed of 0.05~0.1m·s-1 was found in cabin’s aisle and regions near passengers’ heads and shoulders.The simulation strategy proposed in this paper can be regarded as the basement for accurate and efficient simulation of the airflow in whole aircraft cabin.And the results of airflow characteristics in the signal-row cabin and seven-row cabin with personalized vents can provide theoretical guidelines to the further study on the control of environment and contaminants in aircraft.