基于DEM-CFD耦合技术的绝缘子动态积污特性研究
发布时间：2019-07-06 08:06
【摘要】：绝缘子污闪是造成电力系统安全运行故障的主要原因之一。通过对绝缘子的动态积污特性的研究,可以了解绝缘子表面动态积污机理及绝缘子在复杂环境条件下的积污状况;从而可以采取有效措施来减小绝缘子表面积污,以及降低污闪发生的概率。绝缘子积污过程是大气环境中的污秽颗粒与绝缘子表面相互作用并耦合的过程,国内外学者使用过多种方法进行绝缘子积污特性的分析研究,但都没有采用离散元方法(DEM)和计算流体动力学方法(CFD)耦合的技术对绝缘子的积污特性进行数值分析。文章引入离散元技术,通过建立动态积污模型,分析绝缘子动态积污特性,然后采用DEM-CFD耦合技术对标准型和防污型两种棒状绝缘子表面动态积污过程进行数值模拟,并分析污秽颗粒在绝缘子表面沉降的特性,从而根据地势环境、气候条件以及污秽类型等各种影响因素对绝缘子进行选型和安装。文章首先分析绝缘子的动态积污过程,建立了颗粒在外流场运动、颗粒与绝缘子表面接触粘附的动态积污模型。通过对积污模型的计算和分析,得到灰尘颗粒从绝缘子表面脱附所需的最小水平风速。然后根据离散元方法和计算流体力学方法耦合技术,利用仿真软件EDEM和FLUENT,选择合适的数值耦合模拟方法,采用RNG k-ε湍流模型对空气流场进行数值计算,采用JKR模型进行颗粒和绝缘子表面的接触分析,并分析耦合域内污秽颗粒的动力学特性;采用欧拉耦合的方法模拟污秽颗粒在绝缘子表面的沉积过程,并考虑湍流脉动及表面能对颗粒扩散的影响,从而得到绝缘子表面的积污特性,在得到了绝缘子外部流场以及绝缘子表面污秽颗粒累积特性的基础上,分析了气流速度、来流角度、粒径和绝缘子安装倾角等对绝缘子动态积污特性的影响。论文研究结果表明:重力沉降的临界水平风速与粒径呈二次函数关系;颗粒脱附所需的最小水平风速随粒径呈负一次幂函数分布,粒径越小,颗粒吸附性越好,越易粘附在绝缘子表面,粒径增加,颗粒碰撞反弹概率增加,颗粒脱附性能提高;颗粒与上表面碰撞的入射角度小于与下表面碰撞的入射角度,伞裙下表面积污比上表面严重;绝缘子亲水性对颗粒粘附性能影响最大,颗粒润湿性对粘附性能影响最小;对于已粘附颗粒,需要风力剪切流速大于30.8m/s时,颗粒才会被清除。一定时间内,绝缘子表面粘附的污秽颗粒数随时间呈线性增长趋势;随着风速的增加,颗粒粘附速率先增加,然后逐渐下降,粘附速率最大时对应的风速为最适合积污风速,最适积污风速随粒径的增加逐渐降低,降低幅度越来越小;当来流角度为135°左右时,颗粒粘附速率最大;来流角度的变化使颗粒与绝缘子下表面二次碰撞大于上表面,增大了上表面积污。当绝缘子轴线、风向和重力方向不在同一平面内且互相垂直时,积污速率最快,但此时绝缘子安装倾角对积污速率的变化影响不大;绝缘子安装角度主要对绝缘子轴线、风向和重力方向在同一平面内时的绝缘子积污速率变化影响较大;因此,可以根据不同工况下绝缘子表面积污特性,指导不同地区绝缘子的安装,以便减小绝缘子表面积污;同时,可以观察绝缘子表面积污状态,对绝缘子表面可视化清洗提供指导。
[Abstract]:The flashover of the insulator is one of the main causes of the safe operation of the electric power system. Through the study of the characteristics of the dynamic accumulation of the insulator, it is possible to know the mechanism of the surface dynamic accumulation of the insulator and the pollution condition of the insulator under the complicated environmental conditions, so that the surface area of the insulator can be reduced by taking effective measures, and the probability of the occurrence of the pollution flashover can be reduced. The pollution process of the insulator is the process of the interaction and coupling between the pollution particles in the atmospheric environment and the surface of the insulator, and the domestic and foreign scholars have used a variety of methods to analyze the characteristics of the pollution of the insulator. However, no discrete element method (DEM) and computational fluid dynamics (CFD) coupling technique are used to analyze the pollution characteristics of the insulator. In this paper, the discrete-element technique is introduced, and the dynamic accumulation and pollution characteristics of the insulator are analyzed by establishing a dynamic soil-accumulation model, and then a DEM-CFD coupling technique is adopted to perform numerical simulation on the surface dynamic accumulation process of the two rod-shaped insulator surfaces of the standard type and the anti-fouling type, And the characteristics of the settlement of the pollution particles on the surface of the insulator are analyzed, and the type selection and the installation of the insulators are carried out according to various influencing factors such as the terrain environment, the climatic conditions and the pollution type. In this paper, the dynamic deposition process of the insulator is analyzed, and the dynamic deposition model of the particle contact and adhesion between the particles and the surface of the insulator is established. The minimum horizontal wind speed required for desorption of the dust particles from the surface of the insulator is obtained by the calculation and analysis of the pollution model. and then using the simulation software EDEM and FLUENT to select a suitable numerical coupling simulation method according to the discrete element method and the computational fluid dynamics method, and the dynamic characteristics of the dirty particles in the coupling domain are analyzed, the deposition process of the dirty particles on the surface of the insulator is simulated by the method of the Euler coupling, the influence of the turbulent fluctuation and the surface energy on the particle diffusion is taken into account, the pollution characteristics of the surface of the insulator are obtained, On the basis of obtaining the external flow field of the insulator and the accumulation characteristics of the dirty particles on the surface of the insulator, the effect of the gas flow velocity, the flow angle, the particle size and the installation angle of the insulator on the dynamic fouling characteristics of the insulator is analyzed. The results of the research show that the critical horizontal wind speed of the gravity settlement is the quadratic function relation with the particle size, the minimum horizontal wind speed required by the particle desorption is distributed with a negative power function with the particle size, the smaller the particle size, the better the particle absorption, the more easily adhered to the surface of the insulator, the particle size is increased, the particle collision rebound probability is increased, the particle desorption performance is improved, the incident angle of the collision between the particles and the upper surface is smaller than the incident angle of the collision with the lower surface, the surface area of the umbrella skirt is more serious than the upper surface, and the hydrophilicity of the insulator is the biggest influence on the adhesion performance of the particles, The particle wettability has a minimum effect on the adhesion performance; for the adhered particles, the particles will be removed only when the wind shear flow rate is greater than 30.8 m/ s. During a certain period of time, the number of dirty particles adhered to the surface of the insulator increases linearly with time, The optimum pollution-free wind speed decreases with the increase of the particle size, and the decreasing range is smaller and smaller; when the flow angle is about 135 掳, the particle adhesion rate is the most; the change of the flow angle causes the secondary collision of the particles and the lower surface of the insulator to be larger than the upper surface, and the upper surface area is increased. when the axis of the insulator, the wind direction and the gravity direction are not in the same plane and are perpendicular to each other, the pollution rate is the fastest, when the wind direction and the gravity direction are in the same plane, the change of the pollution rate of the insulator is relatively large; therefore, the installation of the insulator in different regions can be guided according to the characteristics of the surface area pollution of the insulator under different working conditions, so that the surface area of the insulator is reduced; and meanwhile, The surface area of the insulator can be observed, and the visual cleaning of the surface of the insulator can be provided.
【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】：TM216
[Abstract]:The flashover of the insulator is one of the main causes of the safe operation of the electric power system. Through the study of the characteristics of the dynamic accumulation of the insulator, it is possible to know the mechanism of the surface dynamic accumulation of the insulator and the pollution condition of the insulator under the complicated environmental conditions, so that the surface area of the insulator can be reduced by taking effective measures, and the probability of the occurrence of the pollution flashover can be reduced. The pollution process of the insulator is the process of the interaction and coupling between the pollution particles in the atmospheric environment and the surface of the insulator, and the domestic and foreign scholars have used a variety of methods to analyze the characteristics of the pollution of the insulator. However, no discrete element method (DEM) and computational fluid dynamics (CFD) coupling technique are used to analyze the pollution characteristics of the insulator. In this paper, the discrete-element technique is introduced, and the dynamic accumulation and pollution characteristics of the insulator are analyzed by establishing a dynamic soil-accumulation model, and then a DEM-CFD coupling technique is adopted to perform numerical simulation on the surface dynamic accumulation process of the two rod-shaped insulator surfaces of the standard type and the anti-fouling type, And the characteristics of the settlement of the pollution particles on the surface of the insulator are analyzed, and the type selection and the installation of the insulators are carried out according to various influencing factors such as the terrain environment, the climatic conditions and the pollution type. In this paper, the dynamic deposition process of the insulator is analyzed, and the dynamic deposition model of the particle contact and adhesion between the particles and the surface of the insulator is established. The minimum horizontal wind speed required for desorption of the dust particles from the surface of the insulator is obtained by the calculation and analysis of the pollution model. and then using the simulation software EDEM and FLUENT to select a suitable numerical coupling simulation method according to the discrete element method and the computational fluid dynamics method, and the dynamic characteristics of the dirty particles in the coupling domain are analyzed, the deposition process of the dirty particles on the surface of the insulator is simulated by the method of the Euler coupling, the influence of the turbulent fluctuation and the surface energy on the particle diffusion is taken into account, the pollution characteristics of the surface of the insulator are obtained, On the basis of obtaining the external flow field of the insulator and the accumulation characteristics of the dirty particles on the surface of the insulator, the effect of the gas flow velocity, the flow angle, the particle size and the installation angle of the insulator on the dynamic fouling characteristics of the insulator is analyzed. The results of the research show that the critical horizontal wind speed of the gravity settlement is the quadratic function relation with the particle size, the minimum horizontal wind speed required by the particle desorption is distributed with a negative power function with the particle size, the smaller the particle size, the better the particle absorption, the more easily adhered to the surface of the insulator, the particle size is increased, the particle collision rebound probability is increased, the particle desorption performance is improved, the incident angle of the collision between the particles and the upper surface is smaller than the incident angle of the collision with the lower surface, the surface area of the umbrella skirt is more serious than the upper surface, and the hydrophilicity of the insulator is the biggest influence on the adhesion performance of the particles, The particle wettability has a minimum effect on the adhesion performance; for the adhered particles, the particles will be removed only when the wind shear flow rate is greater than 30.8 m/ s. During a certain period of time, the number of dirty particles adhered to the surface of the insulator increases linearly with time, The optimum pollution-free wind speed decreases with the increase of the particle size, and the decreasing range is smaller and smaller; when the flow angle is about 135 掳, the particle adhesion rate is the most; the change of the flow angle causes the secondary collision of the particles and the lower surface of the insulator to be larger than the upper surface, and the upper surface area is increased. when the axis of the insulator, the wind direction and the gravity direction are not in the same plane and are perpendicular to each other, the pollution rate is the fastest, when the wind direction and the gravity direction are in the same plane, the change of the pollution rate of the insulator is relatively large; therefore, the installation of the insulator in different regions can be guided according to the characteristics of the surface area pollution of the insulator under different working conditions, so that the surface area of the insulator is reduced; and meanwhile, The surface area of the insulator can be observed, and the visual cleaning of the surface of the insulator can be provided.
【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】：TM216
【参考文献】
相关期刊论文 前10条
1 王黎明;刘霆;黄睿;梅红伟;项阳;;考虑气象、几何参数、大气污染物的绝缘子表面污秽度预测方法[J];高电压技术;2016年03期
2 王黎明;刘霆;梅红伟;项阳;;基于计算流体力学的支柱绝缘子积污特性研究[J];高电压技术;2015年08期
3 王辉;焦杨;辛文宇;杨元勋;谢x，
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