本文選題：水沖洗 + 清洗效率��； 參考：《西南交通大學(xué)》2017年碩士論文

【摘要】：電力作為現(xiàn)代社會(huì)一種不可或缺的能源,與人類的日常生活和工業(yè)生產(chǎn)息息相關(guān),對(duì)經(jīng)濟(jì)發(fā)展具有無可替代的巨大作用,所以保障電氣設(shè)備的正常運(yùn)行是非常重要的。而隨著工農(nóng)業(yè)的迅猛發(fā)展,對(duì)外界排放的各種污染物也不斷增加,大氣中的懸浮物呈現(xiàn)出多種類、大密度的趨勢(shì),供電系統(tǒng)的外絕緣電氣設(shè)備極易沾染到這些污穢,進(jìn)而影響其絕緣性能,造成污閃事故,給工業(yè)生產(chǎn)帶來重大損失,并對(duì)日常生活造成影響。因此,對(duì)電力設(shè)備進(jìn)行及時(shí)清洗具有重要的意義,而絕緣子作為供電系統(tǒng)中最基礎(chǔ)、應(yīng)用最廣的元件之一,保證其清潔更是重點(diǎn)中的重點(diǎn)。本文通過理論分析了絕緣子污穢的粘附力和清除機(jī)理,然后運(yùn)用CFD軟件進(jìn)行數(shù)值模擬研究,分析射流打擊力隨噴嘴出口直徑、靶距、沖洗角度及進(jìn)口壓力等參數(shù)的變化趨勢(shì),并分析傘裙結(jié)構(gòu)及濺射水對(duì)絕緣子帶電水沖洗的影響,為絕緣子帶電水沖洗提供參考依據(jù),能夠更安全高效的完成清洗作業(yè)。本文主要內(nèi)容如下:1、絕緣子污穢間的粘附力主要由范德華力和毛細(xì)作用力組成,通過簡(jiǎn)化模型計(jì)算得到污穢顆粒與絕緣子表面間的粘附力為2.2×10-5N,顆粒間的粘附力為1.1×10-5N。污穢顆粒在射流清洗作用下有著不同的脫附機(jī)理,以計(jì)算得到的粘附力為基礎(chǔ),通過分析污穢顆粒在射流中的受力情形,認(rèn)為污穢更容易通過滾動(dòng)的方式、成對(duì)的從絕緣子表面脫離。2、通過Fluent對(duì)射流打擊力特性進(jìn)行了仿真分析,依靠Matlab擬合得到三種噴嘴出口直徑下的射流打擊力函數(shù),可知射流水柱打擊力隨著進(jìn)口壓力的增加而顯著提高,隨著靶距的增加急劇下降,因此,在保證安全沖洗的前提下,增加噴嘴進(jìn)口壓力和縮短靶距是提高清洗效率的有效方式;沖洗角度的不同會(huì)導(dǎo)致射流速度、射流壓力和射流厚度分布不均勻,使得射流軸心附近的清洗效果存在差異,當(dāng)沖洗角度為20°和30°時(shí)具有更高的清洗效率,應(yīng)優(yōu)先選擇;增加噴嘴直徑能有效提高射流打擊力,但是也會(huì)導(dǎo)致更大的流量和能量消耗,由于流量和能量對(duì)壓力更不敏感,所以在提升打擊力時(shí)應(yīng)優(yōu)先選擇提升壓力的方式。3、對(duì)于三種不同的傘裙結(jié)構(gòu),其下傘面水流流動(dòng)情形在不同沖洗角度下存在一定的差異,主要是由其結(jié)構(gòu)特征導(dǎo)致,但其近壁面速度隨壓力變化趨勢(shì)一致;在沖洗角度較大時(shí),水柱所攜帶的動(dòng)能直接作用在污穢上,且垂向速度分量增加,能更有效的破碎污穢,在污穢粘附強(qiáng)度較大時(shí),應(yīng)選擇較大沖洗角度;近壁面水平速度分量隨沖洗角度增加而減小,在滿足臨界清洗壓力要求后,選擇較小沖洗角度,能提高清洗效率;綜合不同絕緣子結(jié)構(gòu)的下傘面水流特性、近壁面射流速度及有效清洗面積,當(dāng)沖洗角度為20°時(shí)能保證更高的沖洗效率,應(yīng)優(yōu)先選擇。4、濺射水對(duì)沖洗工作有多方面的影響,首先濺射水能有效增加沖洗面積,對(duì)提高.工作效率有著積極的意義,但也會(huì)使絕緣子表面泄漏電流增加或?qū)е虑逑催^程中出現(xiàn)污水連線和濺射閃絡(luò),增加帶電水沖洗作業(yè)的安全風(fēng)險(xiǎn);濺射水會(huì)提前潤(rùn)濕軟化污穢,改變污穢的性質(zhì)和強(qiáng)度,使得污穢清除機(jī)理由滲透水內(nèi)應(yīng)力擠壓變?yōu)樯淞鞯闹苯記_擊和剪切;同時(shí)濺射水通過改變環(huán)境的相對(duì)濕度增加了污穢與絕緣子.間粘附力,但對(duì)所需清洗動(dòng)壓影響不大。
[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.

【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TM75;TM216

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