Evaluation of various categories of turbulence models for predicting air distribution in an airliner cabin

Flow fields in commercial airliner cabins are crucial for creating a thermally comfortable and healthy cabin environment. The study of flow fields in cabins could be achieved by numerically solving Navier-Stokes equations with a suitable turbulence model. This investigation evaluated three turbulence models in different categories: the RNG k-ε model, LES, and DES for the steady-state flow in the first-class cabin of a functional MD-82 commercial airliner. The measured flow fields under unoccupied and fully-occupied conditions in the first-class cabin were used for validating the turbulence models. The flow in the unoccupied cabin was isothermally forced convection created by air jets from the diffusers, while the flow in the fully-occupied cabin was mixed convection driven by both the jets and thermal plumes from the thermal manikins used to simulate passengers. This study found that the RNG k-ε model gave acceptable accuracy in predicting the airflow in the unoccupied cabin where the flow was simple, but not for the complicated flow in the fully-occupied cabin. The DES gave acceptable flow fields for both cabins. The LES performed the best and the results agreed well with the experimental data. Comparing the measured flow fields in the two cabin conditions, this study found that the thermal plumes from the heated manikins had a significant influence on the flow fields, but little influence on the turbulence.