Research On The Character Of Ejection Flow In Electrified Railways Insulator Water Washing

As the national railway electrification technology promotion, pollution flashover of insulators is a key factor which influence the normal operation of train, frequent pollution flashover trip is very harmful to normal power supply of catenary. At present, the most time-saving and the most effective method avoiding catenary insulator filthy functionaries is adopting water hot washing vehicle to rinse. But the nozzle performance greatly influences the vehicle's work efficiency, and its study is one of the key points in the whole process of developing water hot washing vehicle.This article takes the basic principle of Computational Fluid Dynamics on the basis of full understanding to the non-submerged jet, adopts the VOF multiphase flow control equations and K-s/High Reynolds Number turbulent model and simulates numerically to the jet flow field based on star-cd solver, analysis the two-phase flow feature. And under the circumstance of an identical boundary condition and initial condition, through changing respectively the diameter of nozzle exit, the contraction angle of cone segment and the length diameter ratio of three construct parameter of nozzle and inside surface roughness and process chamfering of two technology parameter, and sampling the datum in the difference cross sections which are perpendicular to the jet axis, analyses these parameters'influence to the velocity attenuation and gets the best nozzle structure and process parameters combination. Secondly, analyses the influence of hydraulic parameter by choosing one of the group of parameters and changing the inlet pressure. The results show that, the structural parameters of nozzle such as the diameter of nozzle exit can increase the jet speed, the influence of length-diameter ratio mainly change the jet boundary layer thickness, and the bset value should be 1.0, smaller contract Angle can increase the jet and waterspout's intensive. Meanwhile, the process parameters of export chamfering and roughness will increase boundary layer thickness and reduce waterspout's intensive. The inlet pressure can increase the jet intensive, reduce the speed of the attenuation cross section and increased axial speed.Finally, the rectifier structure which is in the rod of cannon was designed and three dimensional CFD numerical methods were used to simulate the interior and exterior flow field of nozzle and cannon, and analyzes and studies structure shape, location, axial dimensions of the rectifier to the influence on jet properties. The conclusion of the article could provide the reference to the selection of the structure of the nozzle used cleaning and the further optimized and research of cannon stem. The results show that:gun rods in the shape of the rectifier structure, position and axial dimensions respectively affect axial velocity and jet boundary layer thickness.