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Computational fluid dynamics (CFD) is an important and effective tool to study the airflow field and contaminant distribution in aircraft cabins. The accuracy of numerical simulation using the CFD approach could be significantly affected by configurations of the inlet boundary conditions, turbulence model, etc. The core of this study was to assess whether conclusions achieved in simulation of airflow on usual surfaces in buildings like in commercial offices could be applicable to aircraft cabins. Comparative studies involving turbulence models or air supply opening models in aircraft cabin environment are still absent in the literature. Therefore, in this study, two turbulence models (the renormalization group (RNG) k-ɛ model and Reynolds-stress model) and three types of air supply opening models (simple open model, basic model and momentum model) were applied to simulate the airflow and contaminant concentration fields in a mockup seven-row cabin section. Our simulation results were compared with the experimental data. Six indexes based on different criteria were used to quantitatively evaluate the agreement between measurements and modelled results given by turbulence models and air supply opening models. The results show that the RNG k-ɛ and RSM turbulence models have similar accuracy in airflow and contaminant fields in the mockup cabin, and the momentum model has the best accuracy among the three air supply opening models for the aircraft cabin environment.

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The purpose of this study was to investigate the influence of large-scale circulation on the flow field in a cabin mockup. The velocity was measured by ultrasonic anemometers (UA). Then, this study analyzed the turbulence kinetic energy spectra of the velocity fluctuation signal. The turbulence kinetic energy spectra of the measurement points reflect the flow characteristic of the large-scale circulation in the cabin mockup. The results contribute to the understanding of the role of the thermal plume on the large-scale circulation in the cabin. The large-scale circulation's impact on air quality was also investigated, and the contaminant distribution was measured using tracer gas in the cabin. The two large-scale circulation interactions made the air flow mixing approximately uniform.

The airflow distribution characterised by different large- and small-scale eddies in the aircraft cabin is the most important factor to maintain passengers' thermal comfort and to remove contaminants. The airflow distributions in narrow-body aircraft cabins are based on the principle of mixing ventilation. Opposing jets from air diffusers can cause stream deflection and oscillation, which results in the asymmetry of large-scale instantaneous airflow structures. This dynamic airflow structure is very important for analysing time series parameters. Therefore, this study applied numerical simulation to examine the oscillation and asymmetry of instantaneous airflow field structures and phase space reconstruction and used spectrum analysis to evaluate the oscillation amplitude and period of dynamic airflow structure. We also studied the factors that influence the dynamic airflow structure, such as air supply speeds, air supply angles and the strength of the thermal plume. The results showed that as the air supply speed increased, the swing amplitude of the instantaneous airflow structure increased, while the period decreased. The air supply angle affected the jet attachment and collision angle, which in turn affected the swing amplitude and period. The thermal plume restrained the formation of large-scale swings and contributed to the appearance of small-scale structures.

Aircraft cabin mockup has been accepted as a benchmark tool to study the aircraft cabin environment. Some researchers used computational fluid dynamics to predict the cabin environment, but the model always needs to be validated by accurate and comprehensive experimental data obtained from the cabin mockup. This study measured thermo-fluid boundary conditions, airflow and temperature distributions by appropriate instruments in a full-scale seven-row aircraft cabin mockup. We used an improved interpolation method to obtain the airflow and temperature distributions. For airflow fields, the interpolation regions were determined based on the sampling location. For the temperature field, in addition to sampling locations, cabin wall temperatures were also needed to be set as interpolation boundary. Non-uniformity coefficient was applied to evaluate homogeneities of air supply velocities and zonal wall temperatures. The measurement error and uncertainty were quantified in detail to evaluate measurement accuracy. We found that the uncertainty of the air supply velocity measured by hot-sphere anemometers was lower than that of airflow field velocity measured by ultrasonic anemometers.

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