Numerical simulation of formaldehyde distribution characteristics in the high-speed train cabin

The global concern over indoor air pollution in public vehicles has grown significantly. With a focus on enhancing passengers' comfort and health, this study endeavors to investigate the distribution characteristics of formaldehyde within a high-speed train cabin by employing a computational fluid dynamics (CFD) model which is experimentally validated in a real cabin scenario. The research focuses on analyzing the impact of air supply modes, temperature, relative humidity, and fresh air change rate on the distribution and concentration of formaldehyde. The results demonstrate that the difference in average formaldehyde concentration between the two air supply modes is below 1.3%, but the top air supply mode leads to a higher accumulation of formaldehyde near the sidewalls, while the bottom air supply mode promotes a more uniform distribution of formaldehyde. Furthermore, the temperature, relative humidity, and fresh air change rate are the primary factors affecting formaldehyde concentration levels, but they have modest effects on formaldehyde's distribution pattern within the cabin. As the temperature and relative humidity increase, the changes in formaldehyde concentrations in response to variations in these factors become more evident. Importantly, the formaldehyde concentration may surpass the standard limit of 0.10 mg/m³ if the fresh air change rate falls below 212 m³/h. This research provides a systematic approach and referenceable results for exploring formaldehyde pollution in high-speed train cabins.