Research on movement and deposition of snow particles with different shapes in the bogie region

Abstract

Natural snow particles come in various complex shapes and have different forces acting on them. The forces acting on snow particles of various shapes are customised in this study based on the shape correction coefficients and sphericity theories. The wind and snow flow at the bottom of the train are solved by coupling the unsteady Reynolds-averaged Navier–Stokes simulation with the discrete phase model to explore the snow accumulation problem of high-speed train bogies more realistically. The findings reveal that changing the morphology of snow particles impacts their resistance to movement in the bogie region, affecting their mobility in the bogie region. Snow particles with higher resistance will stay in the low-speed zone of the bogie region, increasing snow particle concentration and accumulation, whereas snow particles with lower resistance follow airflow movement and gather fewer in the low-speed zone. Different shapes of snow particles accumulate in different amounts on the bogie components, with the most accumulation by spherical snow particles in the braking system and suspension system surface. Therefore, using spherical snow particles to simulate wind and snow flow phenomenon at the bottom of the train can indicate the worst case.

Research on snow prevention in the bogie region based on active blowing method

“…Owing to the existence of low-speed zones and vortex areas, snow particles cannot facilely leave the bogie region, leading to snow accumulation. 19 Therefore, the main idea of the design proposed in this study is to suppress the uplift of snow particles and render their entry into the bogie region difficult, thereby preventing snow accumulation. A model comprising a full-size head car with a half-section middle car is established, as shown in Figure 2(a).…”

“…A snow particle emission surface is set up 1 m in front of the bogie cavity for snow particle injection, as shown in Figure 2(c). 5,19,22,23 Based on the snowfall rate level, 24 an extremely heavy snowstorm was selected as the snowfall environment at the bottom of the train. A total of 3600 particles were injected into the snow particle emission surface at each time step to introduce a discrete phase.…”

“…The particles have a dendritic shape with a diameter of 150 mm and density of 150 kg/m 3 . 19 The force status of the snow particles was written using a UDF based on the shape correction coefficient proposed by Loth. 25 For the adhesion state of snow particles, the snow particle capture criterion proposed by Cai et al 22,23 was adopted, and the corresponding custom boundary condition was written using a UDF.…”

Analysis of Snow Distribution and Displacement in the Bogie Region of a High-Speed Train

“…Gao et al [20,21] utilized the DPM to investigate the motion, accumulation, and flow of snow around bogie. Lan et al [22] investigated the effect of various shapes of snow particles on snow accumulation in the bogie region and pointed out that using spherical snow particles would result in the most accumulation on the surfaces of the braking and suspension system. Clifton et al [23], based on wind tunnel experiments, improved the snow saltation model using the Euler-Lagrange method.…”