Objective In the enclosed environment of high-speed train passenger compartments, air circulation is restricted, and pollutants may accumulate and spread within the limited space, directly affecting passenger comfort and safety. The propagation of pollutants is influenced not only by air movement and ventilation modes, but also by factors such as passenger activities, pollution sources distribution, and compartment geometric structure. Improving the flow field environment within the passenger compartment can not only enhance ride comfort but also effectively improve air quality and reduce the accumulation and diffusion of harmful substances inside the compartment, thereby improving passenger safety during travel. Therefore, it is necessary to conduct research on this issue.

Method The current research status in the fields of ride comfort, flow field characteristics, and virus transmission in passenger compartments of high-speed trains and metro trains in the world is systematically investigated and summarized. The distribution patterns of temperature fields and airflow fields in different passenger compartment areas are analyzed. From the perspective of zonal control, multiple exhaust outlets are added at the bottom of the passenger compartment (a total of six additional schemes), enabling pollutants in each area to be discharged in a timely manner, reducing the residence time of pollutants within each zone, thus decreases the propagation range of particulate matter inside the compartment, and effectively suppresses the spatial diffusion of pollutants.

Result & Conclusion  After adding exhaust outlets at the bottom of the passenger compartment, the residence time of pollutant in low-velocity residence zones can be effectively reduced. A comparative simulation analysis of multiple schemes shows that under the exhaust outlet configuration that achieves the optimal suppression effect on the longitudinal propagation of droplets, the maximum longitudinal diffusion distance of droplets is 5.32 m at 60 s, and 9.81 m at 120 s.