Numerical study on effect of crosswind on the cooling-fan flow and smoke diffusion of power pack suspended under the diesel train

Abstract

Development of power packs suspended under the diesel train towards high power and high integration has been driven by the development of technology. The wind environment of the railway lines is complex and variable, strong crosswind would exacerbate the complexity of the airflow around the train, impacting the cooling-fan performance of power pack, smoke dispersion, posing safety concerns. Using incompressible RANS equations and SST k-ω model, flow field around a diesel train, and effect of train speed, crosswind, and skirt board on cooling-fan flow and smoke dispersion are simulated and analyzed. Results reveal that airflow in power pack fans is affected by train speed and location, with the upstream fan exhibiting slightly higher airflow, especially in tail car power packs, with a difference of up to 7% (at 160 km/h). Skirt boards reduce fan airflow by about 6%. Crosswinds positively correlate with fan airflow variation, with windward and leeward fans experiencing increased and decreased airflow, respectively. Skirt board effectively reduces crosswind effects on power pack fans. Smoke intake into air-conditioning units (ACUs) correlates positively with train speed, particularly in downstream air-intakes of ACUs near smoke vents. Crosswinds significantly alter smoke distribution between leeward and windward sides of ACUs, especially at low crosswind speed. Smoke rarely enters ACUs when crosswind speed exceeds train speed. These findings offer insights for combustion-powered train operation and smoke vent design on train roofs.

Keywords

• Diesel train
• Power pack
• Cooling-fan performance
• Smoke diffusion
• Crosswind