翻译：4 雪粒的沉积与预防41 雪粒的空间分布雪粒在转向架区域的空间分布平面1如图10所示其中方案1和方案2的吹气速度均为4 ms。雪粒在空间突然扩张和轮对旋转的作用下进入转向架区域在转向架2和转向架3区域由于转向架区域的流速相对较低雪粒不易随气流流出转向架区域而是在低速区和涡旋区滞留；由于雪粒从列车鼻尖底部释放部分雪粒黏附或者停留在转向架1和转向架2区域后剩下的雪粒才跟随气流运动至转向架3区域所

Snow Grain Deposition and Prevention 4.1 Spatial Distribution of Snow Grains The spatial distribution of snow grains in the bogie area (plane 1) is shown in Figure 10 for both scheme 1 and scheme 2 blowing at a speed of 4 m/s. Snow grains enter the bogie area due to sudden expansion and wheel rotation. In the bogie 2 and bogie 3 areas, the flow velocity is relatively low, and snow grains are not easily carried out of the bogie area by the airflow but remain in the low-speed and vortex areas. Since snow grains are released from the bottom of the train nose, some snow grains adhere or remain in the bogie 1 and bogie 2 areas, and the remaining snow grains follow the airflow to the bogie 3 area. Therefore, the snow grain content in the bogie 3 area is relatively low. In addition, the flow velocity in the bogie 1 area is higher, and the ability of the airflow to carry snow grains is stronger, making it easier for snow grains to flow out of the bogie area. However, there are still some low-speed areas, so the spatial distribution of snow grains in the bogie 1 area is not as dispersed as in the bogie 2 and bogie 3 areas. Instead, snow grains are mainly concentrated in certain areas, and the snow grain concentration in these areas is much higher than 1×10−4 kg/m3. In the bogie 1 area, the snow grain uplift phenomenon is particularly obvious in the original model, and it can eventually fill the entire bogie area. In scheme 2, although snow grains can rise to the surface of the bogie cabin, there are basically no snow grains near the blowing port, and the snow grain concentration at the top of the bogie is lower than that of the original model. In scheme 1, the height of the snow grain uplift is basically the same as the height of the brake disc top, which is more effective in suppressing snow grain uplift. In the bogie 2 and bogie 3 areas, due to the low flow velocity, the upward airflow in the entire space is significantly suppressed in both blowing schemes, which makes it difficult for the airflow to carry snow grains into the bogie area. As a result, there are basically no snow grains distributed at the top of the bogie, and the effect of blowing is more significant. Therefore, scheme 1 and scheme 2 reduce the snow grain concentration in the bogie area and can effectively reduce the amount of snow accumulation on the bogie surface. 4.2 Snow Grain Deposition Figure 11(a) shows the surface snow distribution of the bogie 2 in the original model and the two design schemes under a blowing speed of 4 m/s. It can be clearly seen that the snow distribution on the surface of the bogie is related to the friction wind speed, and the blue area in Figure 6-6 basically coincides with the red area in Figure 6-9(a), indicating that snow grains in this area can stably deposit on the surface of the bogie. On the contrary, there are no snow grains adhering to the surface of the bogie in the area where the friction wind speed is greater than 1 m/s. In addition, although scheme 2 is designed for key components, it can be clearly seen that the snow accumulation phenomenon on components such as the brake caliper and air spring is more severe than in scheme 1. Figure 11(b) shows the surface snow distribution of the bogie 2 in scheme 1 under blowing speeds of 1-3 m/s. With the increase of blowing speed, the snow accumulation on the surface of the bogie decreases rapidly, and there is basically no snow accumulation on the surface of the frame and brake caliper near the blowing port. The snow accumulation caused by blowing mainly occurs on the underside of the bogie, such as the frame crossbeam, air spring mounting seat, and vertical damper mounting seat, which have flat and corner geometries, and blowing cannot cause snow grains on their surface to move downward to leave the bogie area. 4.3 Evaluation of Blowing Schemes 4.3.1 Snow Prevention Rate Evaluation As described in section 4.2, the snow prevention effect of blowing scheme 1 is more obvious, but scheme 1 requires more energy consumption due to its larger air supply volume. The snow prevention rates of the two schemes need to be evaluated to compare their effectiveness under the same air supply volume. The total snow prevention rate RTi and the key component (excluding the bolster and frame) snow prevention rate RKi of the two schemes are defined as follows: where the subscript i represents the position of the bogie, the subscript T represents all components of the bogie, and the subscript K represents the key components of the bogie; ΔM represents the amount of snow reduced, M represents the snow accumulation in the original model; VIN represents the blowing speed; SIN represents the blowing port area, as shown in Table 6-3; RTi and RKi are in units of s/m3, which means the proportion of snow reduction per unit of air supply volume. For example, in Figure 6-10(c), when the blowing speed is 4 m/s, an air supply volume of 1 m3/s can reduce the snow accumulation in the bogie 3 area by 3.45%. Figures 12(a) and 12(b) show the ratio of snow reduction for the two schemes in terms of the total snow accumulation and the accumulation on key components as the blowing speed increases. It can be seen that as the blowing speed increases, the proportion of snow reduction in both the total snow accumulation and the accumulation on key components gradually increases. Figures 12(c) and 12(d) show that the RTi and RKi do not increase with the blowing speed but reach the maximum value when the blowing speed is 2 m/s or 3 m/s. The snow prevention effect of scheme 2 on key components is not significantly better than that of scheme 1, and its effect is only more prominent in the key components of bogie 3. In addition, the snow prevention rates of the bogies are ranked from high to low as bogie 3, bogie 2, and bogie 1, because the flow velocity in bogie 1 is the highest, and the movement speed of snow grains is relatively high.