Flow field characteristics in high-speed train cabin: Negative effect of non-vertical air supply

Abstract

Ventilation systems are critical for improving the cabin environment in high-speed trains, and their interest has increased significantly. However, whether air supply non-verticality deteriorates the cabin air environment, and the flow mechanism behind it and the degree of deterioration are not known. This study first analyzes the interaction between deflection angle and cabin flow field characteristics and ventilation performance. The results revealed that the interior temperature and pollutant concentration decreased slightly with increasing deflection angle, but resulted in significant deterioration of thermal comfort and air quality. This is evidenced by an increase in both draught rate and non-uniformity coefficient, an increase in the number of measurement points that do not satisfy the micro-wind speed and temperature difference requirements by about 5% and 15%, respectively, and an increase in longitudinal penetration of pollutants by a factor of about 5 and the appearance of locking regions at the ends of cabin. The results also show that changing the deflection pattern only affects the region of deterioration and does not essentially improve this deterioration. This study can provide reference and help for the ventilation design of high-speed trains.

Supplementary materials

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Keywords

high-speed trains / non-vertical air supply / ventilation / CFD simulation

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