列车管空气流量计流量感应器的流场特性研究

Flow Field Characteristics of Flow Sensor in Flow Meter for Train Air Brake Pipe

为分析列车管空气流量计流量感应器的机械强度是否能够承受列车管充、排风时气流的频繁冲击,以CHT-LGT1-LB型列车管空气流量计和C61型货车的列车管为例,采用流体力学仿真分析软件分别建立1辆车编组和2辆车编组的列车管气动仿真模型,采用有限体积法求解列车管内的充、排风流场,采用Roe算法求解对流项,采用Rugge-kutta迭代法推进求解时间;根据仿真计算结果对比分析不同编组条件下列车管充、排风时流量感应器的保护罩和传感器表面的冲击压应力分布情况。结果表明:流量感应器保护罩和传感器表面受到的最大压应力与列车编组的辆数无关;保护罩和传感器表面受到的最大压应力出现在充风开始后的0.026和0.028s时和排风的开始时刻,分别为1.1和0.9 MPa,受到的最大弯曲应力分别为0.59和13 MPa;按3倍的安全系数考虑,保护罩和传感器的最大受力均远小于其制造材料的静态机械强度。

In order to analyze whether the mechanical strength of the flow sensor in the flow meter for train pipe could withstand the frequent impact of airflow during charging and discharging,taking CHT-LGT1-LB type flow meter and the train pipe of C61 freight train for examples,the simulation software of hydrodynamics was adopted to establish respectively the aerodynamic simulation models for the air brake pipes of trains with one-wagon and two-wagon formations.The finite volume method was used to solve the charging and discharging flow field in train pipe.The convection term was worked out by the Roe algorithm,and time-marching was performed by a Rugge-Kutta iterative method.Based on simulation results,comparative analyses were carried out on the distributions of impact compressive stress on the protective cover and the surface of flow sensor during the charging and discharging of train pipe under different train formations.Results indicated that the maximum compressive stress on the protective cover and the surface of flow sensor had nothing to do with the number of wagons in the train formation.The maximum compressive stress on the protective cover and the surface of flow sensor,which was 1.1and 0.9MPa respectively,occurred at 0.026 and 0.028 safter the start of charging and at the start time of discharging.The maximum bending stress was 0.59 and 13 MPa respectively.Considering 3times of safety factor,the maximum forces of both the protective cover and the sensor were much less than the static mechanical strength of the material.