影响绝缘子带电水冲洗效果的关键因素研究

发布时间：2018-04-22 18:27

本文选题：水冲洗 + 清洗效率　；参考：《西南交通大学》2017年硕士论文

【摘要】：电力作为现代社会一种不可或缺的能源,与人类的日常生活和工业生产息息相关,对经济发展具有无可替代的巨大作用,所以保障电气设备的正常运行是非常重要的。而随着工农业的迅猛发展,对外界排放的各种污染物也不断增加,大气中的悬浮物呈现出多种类、大密度的趋势,供电系统的外绝缘电气设备极易沾染到这些污秽,进而影响其绝缘性能,造成污闪事故,给工业生产带来重大损失,并对日常生活造成影响。因此,对电力设备进行及时清洗具有重要的意义,而绝缘子作为供电系统中最基础、应用最广的元件之一,保证其清洁更是重点中的重点。本文通过理论分析了绝缘子污秽的粘附力和清除机理,然后运用CFD软件进行数值模拟研究,分析射流打击力随喷嘴出口直径、靶距、冲洗角度及进口压力等参数的变化趋势,并分析伞裙结构及溅射水对绝缘子带电水冲洗的影响,为绝缘子带电水冲洗提供参考依据,能够更安全高效的完成清洗作业。本文主要内容如下:1、绝缘子污秽间的粘附力主要由范德华力和毛细作用力组成,通过简化模型计算得到污秽颗粒与绝缘子表面间的粘附力为2.2×10-5N,颗粒间的粘附力为1.1×10-5N。污秽颗粒在射流清洗作用下有着不同的脱附机理,以计算得到的粘附力为基础,通过分析污秽颗粒在射流中的受力情形,认为污秽更容易通过滚动的方式、成对的从绝缘子表面脱离。2、通过Fluent对射流打击力特性进行了仿真分析,依靠Matlab拟合得到三种喷嘴出口直径下的射流打击力函数,可知射流水柱打击力随着进口压力的增加而显著提高,随着靶距的增加急剧下降,因此,在保证安全冲洗的前提下,增加喷嘴进口压力和缩短靶距是提高清洗效率的有效方式;冲洗角度的不同会导致射流速度、射流压力和射流厚度分布不均匀,使得射流轴心附近的清洗效果存在差异,当冲洗角度为20°和30°时具有更高的清洗效率,应优先选择;增加喷嘴直径能有效提高射流打击力,但是也会导致更大的流量和能量消耗,由于流量和能量对压力更不敏感,所以在提升打击力时应优先选择提升压力的方式。3、对于三种不同的伞裙结构,其下伞面水流流动情形在不同冲洗角度下存在一定的差异,主要是由其结构特征导致,但其近壁面速度随压力变化趋势一致;在冲洗角度较大时,水柱所携带的动能直接作用在污秽上,且垂向速度分量增加,能更有效的破碎污秽,在污秽粘附强度较大时,应选择较大冲洗角度;近壁面水平速度分量随冲洗角度增加而减小,在满足临界清洗压力要求后,选择较小冲洗角度,能提高清洗效率;综合不同绝缘子结构的下伞面水流特性、近壁面射流速度及有效清洗面积,当冲洗角度为20°时能保证更高的冲洗效率,应优先选择。4、溅射水对冲洗工作有多方面的影响,首先溅射水能有效增加冲洗面积,对提高.工作效率有着积极的意义,但也会使绝缘子表面泄漏电流增加或导致清洗过程中出现污水连线和溅射闪络,增加带电水冲洗作业的安全风险;溅射水会提前润湿软化污秽,改变污秽的性质和强度,使得污秽清除机理由渗透水内应力挤压变为射流的直接冲击和剪切;同时溅射水通过改变环境的相对湿度增加了污秽与绝缘子.间粘附力,但对所需清洗动压影响不大。
[Abstract]:As an indispensable energy in the modern society, electricity is closely related to the daily life and industrial production of human beings. It has an irreplaceable and irreplaceable role in the development of the economy. So it is very important to ensure the normal operation of the electrical equipment. There are many kinds and large density of the suspended matter in the gas, and the electrical equipment of the external insulation of the power supply system is easily contaminated by these contaminant, which will affect its insulation performance and cause the pollution flashover accident, which brings great loss to the industrial production and affects the daily life. Therefore, it is of great significance to clean the electric power equipment in time. As one of the most basic elements in power supply system, insulators are one of the most widely used components to ensure that the cleaning is the key point. In this paper, the adhesive force and mechanism of insulator contamination are analyzed theoretically. Then the numerical simulation study is carried out by CFD software to analyze the jet impact force with the nozzle exit diameter, target distance, flushing angle and inlet pressure. The change trend of the force and other parameters, and the analysis of the influence of the umbrella skirt structure and the splashing water on the insulators' charged water washing, provide the reference basis for the electrified water flushing of the insulators, and can complete the cleaning operation more safely and efficiently. The main contents of this paper are as follows: 1, the adhesive force between the insulators is mainly composed of the van Edward force and the capillary force. The adhesion force between filth particles and insulator surface is 2.2 * 10-5N, and the adhesion force of the particles is 1.1 x 10-5N. with different adhesion mechanism under the effect of jet cleaning. The adhesion force is based on the calculation of the adhesion force. The contamination is more easily rolled through the analysis of the force situation of the polluted particles in the jet. In the dynamic way, the pair is separated from the surface of the insulator by.2, and the impact force characteristics of the jet are simulated by Fluent. The jet hitting force function under the diameter of the three nozzle exit is obtained by the Matlab fitting. It can be seen that the jet column strike force increases significantly with the increase of the inlet pressure, and thus decreases sharply with the increase of the target distance. Under the premise of safe washing, increasing the inlet pressure of the nozzle and shortening the distance of the target is an effective way to improve the cleaning efficiency. The difference in the flushing angle will lead to the jet velocity, the jet pressure and the distribution of the jet thickness are uneven, which makes the cleaning effect near the jet axis difference. When the flushing angle is 20 and 30 degrees, the cleaning effect is higher. Efficiency, should be selected first; increasing the nozzle diameter can effectively improve the jet impact force, but also lead to greater flow and energy consumption. As the flow and energy are less sensitive to pressure, the way to lift the pressure should be preferred,.3, for three different umbrella skirts. There is a certain difference under different flushing angles, mainly due to its structural characteristics, but its near wall velocity is consistent with the pressure change. When the flushing angle is large, the kinetic energy of the water column is directly acting on the filth, and the vertical velocity component is increased, and it can be more effective to break the foul. The horizontal velocity component of the near wall decreases with the increase of the flushing angle. When the critical cleaning pressure is met, a smaller flushing angle can be selected to improve the cleaning efficiency. The flow characteristics of the lower parachute surface with different insulators structure, the jet velocity near the wall and the effective cleaning area, can guarantee a higher impact when the flushing angle is 20 degrees. Washing efficiency should give priority to the selection of.4. Splashing water has many effects on the washing work. First, the splash water can increase the area of washing effectively. It has a positive significance to improve the working efficiency. But it will also increase the leakage current of the insulator surface or lead to the appearance of sewage line and sputter flashover in the process of cleaning, and increase the safety of the charged water washing operation. Full risk; splashing water will wetting softening and filth in advance, changing the property and strength of pollution, making the pollution scavenging reason permeate the water internal stress extrusion into direct impact and shear of the jet, while splashing water increases the adhesion between pollution and insulators by changing the relative humidity of the environment, but has little effect on the required cleaning dynamic pressure.

【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM75;TM216

【参考文献】