基于DPM模型的高速列车转向架区域风雪流数值模拟

Numerical simulation of the flow and snow particles in the bogie area of a high-speed train based on DPM model

为分析高速列车转向架区域积雪结冰分布规律,采用三维非定常雷诺平均(unsteady Reynolds-averaged Navier-Stokes,URANS)数值模拟方法及离散相模型(discrete phase model,DPM)研究高速列车转向架区域的压力分布、流场流线、雪粒子运动轨迹及积雪堆积情况,并通过对比数值计算与风洞试验结果,验证数值计算方法的准确性。数值计算结果表明:转向架区域由于受气流冲刷,轮对、电机、制动钳夹等突出部件在迎风侧出现明显正压,背风侧则为负压;空气流经转向架迎风侧时会向上扬起,进入转向架的轮对、电机、制动钳夹等关键部位,空气流经转向架背风侧时会冲刷转向架区域的设备舱后端板;空气中的雪粒子不仅具有随动性,还具有惯性,会随气流运动到转向架轮对、电机、制动钳夹等关键部位,并在惯性作用下黏附在其上;积雪堆积主要集中在轮对、电机、制动钳夹以及端板等部件底部迎风区域,而在转向架顶部和背风区域堆积较少。从而得出结论:风场的数值计算结果与风洞试验观测结果具有较高一致性,适用于转向架区域积雪结冰研究;在转向架迎风侧,雪粒子对于气流的跟随性较强,雪粒子的运动轨迹与流场流线分布相符,随气流冲刷至转向架,容易形成积雪结冰;在转向架背风侧以及转向架上方区域,雪粒子对于绕流的跟随程度减弱,不易形成积雪结冰。

In order to analyze the distribution law of snow and ice in the bogie area of high-speed trains,the pressure distribution,the flow field streamline,the trajectory of snow particles and the snow accumulation in the bogie area of a high-speed train were studied by using a combination of three-dimensional unsteady Reynoldsaveraged Navier-Stokes(URANS)numerical simulation method and discrete phase model(DPM).The numerical calculation method was verified by comparing the numerical calculation results with the wind tunnel test results.Numerical results show that the wheels,the motor,the braking caliper and other protruding parts have obvious positive pressure on the windward side and negative pressure on the leeward side due to the air flow scouring.In addition,the air rises and impinges the wheels,the motor,the braking caliper and other key parts of the bogie when the flow through the windward side of the bogie.Then,the flow impinges the equipment compartment rear end panel of the bogie when the flow through the leeward side.The snow particles in the air have both inertia and randomness,moving to the key parts of the bogie with the airflow and adhering to these parts,which results from the action of inertia.Snow accumulation is mainly concentrated in the windward area at the bottom of the wheels,the motor,the braking caliper,the panel,and so on,while it is less accumulated at the top and leeward area of the bogie.It is concluded that the numerical results are in good agreement with the wind tunnel test results,and are suitable for the study of snow accumulation and freezing in the bogie area.On the windward side of the bogie,the snow particles have a strong follow-up to the air flow.The movement trajectory of the snow particles is consistent with the streamline distribution of the flow field.It is easy to form snow and ice when the air flow scours the bogie,and in the leeward side of the bogie and the area above the bogie,the following degree of snow particles to the surrounding flow is weakened,so it is not easy to form accumulation.