| HUANG Qi-rui,ZHANG Shu-yue,WANG Wen-jian,SHI Lu-bing,LIN Qiang,DING Hao-hao.Behaviour and Utilization Rate of SiO2 Particles by Electrostatic Spraying on Rail Surface[J],52(6):196-207 |
| Behaviour and Utilization Rate of SiO2 Particles by Electrostatic Spraying on Rail Surface |
| |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2023.06.017 |
| KeyWord:electrostatic spraying wheel/rail adhesion sanding adhesion viscosity increase particles particle parameters |
| Author | Institution |
| HUANG Qi-rui |
Tangshan Institute, Southwest Jiaotong University, Hebei Tangshan , China |
| ZHANG Shu-yue |
School of Mechanical Engineering, Southwest Jiaotong University, Chengdu , China |
| WANG Wen-jian |
Tangshan Institute, Southwest Jiaotong University, Hebei Tangshan , China;School of Mechanical Engineering, Southwest Jiaotong University, Chengdu , China |
| SHI Lu-bing |
Zhengzhou Research Institute of Mechanical Engineering Co., Ltd., Zhengzhou , China |
| LIN Qiang |
School of Mechanical Engineering, Southwest Jiaotong University, Chengdu , China |
| DING Hao-hao |
Tangshan Institute, Southwest Jiaotong University, Hebei Tangshan , China;School of Mechanical Engineering, Southwest Jiaotong University, Chengdu , China |
|
| Hits: |
| Download times: |
| Abstract: |
| In railway systems, sands are often applied to the wheel-rail interface to improve the adhesion coefficient. However, hard particles such as quartz sand will inevitably cause wear to the wheel and rail after entering the contact area of wheel and rail. The viscosity increase effect of sand sprinkling mainly comes from the broken sand particles and has nothing to do with particle size. Therefore, using SiO2 particles instead of sand particles to increase viscosity can not only meet the viscosity increase effect but also significantly reduce wheel-rail damage. However, due to the small particle size and lightweight of SiO2 particles, it is difficult to effectively apply SiO2 particles to the wheel-rail interface by using the sand spout device in the current railway system. If electrostatic spraying is used to improve the utilization rate of SiO2 particles, it will have a high application prospect. Therefore, the work aims to introduce electrostatic spraying technology into the wheel-rail viscosity increase field and study the effects of different spraying parameters and particle sizes on the behavior and utilization of SiO2 particles, so as to solve the problem of low utilization of SiO2 viscosity increase particles in the traditional sanding process, and further compare and analyze the viscosity increase effects of electrostatic spraying particles and traditional sanding. The rail material selected in the test was U75V rail cut at each section of 50 cm from the site, and the size of SiO2 micro-powder was 100, 200, 300 and 500 mesh, and the content of silica in SiO2 micro-powder was more than 95%. Before each coating test, the rail surface was sanded, polished and cleaned with anhydrous ethanol and the spray gun was flushed with compressed air to prevent powder from blocking the muzzle, and the grounding wire was fixed to the rail. During the test, the Gema electrostatic spray gun was fixed on the rodless slider of the dynamic test bench. At the end of the coating test, it stood for 5 min, and after the suspended particles in the air were completely deposited, the particles adsorbed on the rail surface were collected and weighed by an electronic balance, and then the effective utilization rate was calculated, and the particle adsorption was observed by an optical microscope. Compared with the traditional spraying method, the amount of SiO2 particles on the rail surface by electrostatic spraying increased about 3.8 times. When the electrostatic voltage was increased from 30 kV to 70 kV, the particle utilization rate increased by 60%, but when the electrostatic voltage was further increased to 90 kV, since the particle charge tended to saturate, the particle utilization rate only increased by 10%. The utilization rate of SiO2 particles firstly increased and then decreased with the increase of nozzle height and particle size. When the nozzle height was 25 cm and the particle size was 300 mesh, the particle utilization rate was the highest, reaching 60%. When the electrostatic voltage of the 300 mesh SiO2 particles was 90 kV, the spraying time of the spray gun on the unit distance was relatively shortened with the increase of the moving speed of the spray gun. Therefore, the number of spraying particles on the rail surface of the spray gun decreased with the increase of the speed. When the nozzle height was 10 and 25 cm, the particle utilization rate increased with the increase of flow rate. When the nozzle height was 35 cm, the particle utilization rate increased firstly and then decreased with the increase of the gun moving speed. Compared with the nozzle of 1 m/s, the particle utilization rate of 9 m/s nozzle height at 10 and 25 cm increased by 8% and 7% respectively, while the particle utilization rate at 35 cm decreased by 8%. When 2 g viscous particles were sprayed on a single time, the adhesion enhancement effect of direct spraying SiO2 particles was lower than traditional sand spraying and electrostatic spraying. At electrostatic voltage of 90 kV, the maximum adhesion coefficient of SiO2 particles by electrostatic spraying was close to traditional sand spraying, and the action revolution was 400 revolutions, which was 8 times of that under direct spraying SiO2 particles and 2.2 times of that under traditional sand spraying. When the amount of sand was 5 g/min, the adhesion coefficient of SiO2 particles by 90 kV electrostatic spraying was 0.28, which was close to 0.3 of traditional sand spraying, and the wheel-rail damage was only 75% and 65% of that under traditional sand spraying. The damage to wheel-rail increased by direct spraying SiO2 particles was 66% and 57% of that under traditional sand spraying, but its adhesion coefficient was lower than 0.2. Electrostatic spraying technology can effectively improve the utilization rate of SiO2 particles on the rail surface and enhance the adsorption of particles on the rail surface. The adhesion coefficient of electrostatic spraying SiO2 particles is similar to that under traditional sanding, and the wheel-rail damage rate is lower. |
| Close |
|
|
|