高速气流环境下的车顶绝缘子表面沙粒沉积特性

Deposition Characteristics of Sand on Roof Insulator Surface Under High Speed Airflow Environment

研究车顶绝缘子高速气流环境下的积污特性对指导列车绝缘子运维策略减少污闪事故有重要意义,而现有的气固两相流仿真模型未考虑污秽颗粒的滑移现象,不适用于模拟高速气流环境下车顶绝缘子表面积污过程。为此以环氧树脂车顶绝缘子为研究对象,分析了高速气流下沙粒在绝缘子表面上的受力和运动,认为高速气流环境下需考虑已沉积沙粒在绝缘子表面的滑移运动并提出了相应的判据,建立高速气流环境绝缘子表面沙粒沉积仿真模型,分析了不同气流速度下环氧树脂绝缘子表面沙粒沉积特性,并通过风洞系统开展的绝缘子沙粒沉积试验验证了模型的有效性。仿真和试验结果均表明:环氧树脂绝缘子迎风面沙粒沉积量随着气流速度的增大而减小,背风面沙粒沉积量随气流速度的增大先增多后减少。其主要原因是气流曳力导致迎风面已经沉积的沙粒向背风面移动或离开绝缘子表面重新回到气流场中。

It is of great significance to study the contamination characteristics of the roof insulator under high speed airflow environment,which can guide the operation and maintenance strategy of the train insulator and reduce the flashover accidents.However,the slip phenomenon of particles is not taken into account in the existing gas-solid two-phase flow simulation model,which is not suitable for simulating the contamination process of the roof insulator under high speed airflow environment.Consequently,taking the epoxy resin roof insulator as the research object,we analyzed the forces and movements of sand on the insulator surface under high speed airflow.The slip motion of the deposited sand on the insulator surface should be considered under high speed airflow and the corresponding criterion was proposed,and a hydrodynamic simulation model was built.On the basis of the previous results,the deposition characteristics of sand on the epoxy resin insulator surface under different airflow velocities were analyzed,and the effectiveness of the model was verified by the sand deposition tests carried out in the wind tunnel system.The simulations and experimental results show that the deposition quality of sand on the windward surface of epoxy resin insulator decreases with the increase of airflow speed,the deposition quality of sand on the leeward surface increases first and then decreases with the increase of the airflow speed.The main reason is that the air drag force causes the deposited sand on the windward surface to move toward the leeward surface or leave the insulator surface and return to the airflow field.