电除尘器气流分布与粉尘运动特性的数值分析

发布时间：2018-05-23 20:58

本文选题：电除尘器 + CFD　；参考：《东北电力大学》2015年硕士论文

【摘要】：人类进入二十一世纪以来，随着世界经济迅猛发展，能源的消耗不断曾多，，使人们所居住的环境每况日下。其中空气污染最为严重，造成空气污染的罪魁祸首就是粉尘，而大多数粉尘来自电厂的排放，这就使燃烧产生的颗粒物的排放引起国内外的广泛关注。静电除尘器作为电厂的主要除尘设备，如何提高电除尘器的除尘效率成为电除尘研究者所关注的热点问题。电除尘器内的气流与粉尘颗粒的分布是影响电除尘器的重要因素。为优化流场，研究粉尘颗粒在流场中的运动规律，本文采用CFD的方法对电除尘器内的流场及气固两相流进行模拟计算，得到合理的模拟方法，为电除尘器内气流分布板的设计、调整和改造提供计算依据。对提高电除尘器的环境效益和经济效益均有重要意义。本文在分析了国内外关于电除尘器内部流场和粉尘运动的基本原理的基础上，运用商业软件Fluent对一台300MW的火电机组电除尘器进行模拟计算。首先，采用标准的k模型，基于SIMPLE算法对电除尘器的流场进行模拟并与实验进行对比。在模拟过程中对于电除尘器的气流分布板采用多孔介质模型进行模拟，通过调整气流分布板的开孔率，在电场内形成均匀气流流场与斜气流流场。接着运用欧拉—拉格朗日方法，对连续相采用标准的k模型；对离散相采用离散相模型中随机游走模型，进行双相耦合模拟计算。并在此基础上对两种流场下粉尘颗粒的运动进行分析，并对细微颗粒进行模拟计算，对比分析两种流场对颗粒运动的影响，发现斜气流流场更有利于电除尘器对粉尘补集，提高除尘器除尘效率。然后，分析了两种流场下风速对电除尘器内颗粒运动及除尘效率的影响，得出风速越高除尘效果越差。数值模拟结果表明本模拟方法有一定的可靠性，可为电除尘器的设计和改造提供计算依据。同时证明斜气流技术更有助于提高电除尘效率。
[Abstract]:Since the 21 century, with the rapid development of the world economy, the energy consumption has been increasing. Among them, the air pollution is the most serious, and the main culprit of air pollution is dust, and most of the dust comes from the emission of power plant, which makes the emission of particulate matter produced by combustion cause widespread concern at home and abroad. Electrostatic precipitator (ESP) is the main dedusting equipment in power plant. How to improve the efficiency of ESP has become a hot issue. The distribution of air and dust particles in ESP is an important factor affecting ESP. In order to optimize the flow field and study the movement law of dust particles in the flow field, the CFD method is used to simulate the flow field and gas-solid two-phase flow in the electrostatic precipitator. The reasonable simulation method is obtained, which is the design of the airflow distribution plate in the electrostatic precipitator. Adjustment and reconstruction provide basis for calculation. It is of great significance to improve the environmental and economic benefits of ESP. Based on the analysis of the basic principles of the internal flow field and dust movement of the electrostatic precipitator at home and abroad, the commercial software Fluent is used to simulate the electrostatic precipitator of a thermal power unit with 300MW. Firstly, the standard k model is used to simulate the flow field of ESP based on SIMPLE algorithm. In the process of simulation, the porous media model is used to simulate the air distribution plate of the electrostatic precipitator. By adjusting the opening rate of the gas distribution plate, the uniform flow field and the oblique flow field are formed in the electric field. Then the standard k model is used for the continuous phase and the random walk model in the discrete phase is used for the discrete phase by using the Euler-Lagrangian method. On this basis, the movement of dust particles under two flow fields is analyzed, and the fine particles are simulated and calculated. The effects of the two flow fields on the particle movement are compared and analyzed. It is found that the oblique flow field is more favorable to the dust collection of the electrostatic precipitator. Improve the dust removal efficiency of the dust collector. Then, the effect of wind speed on particle movement and dust removal efficiency in electrostatic precipitator is analyzed. It is concluded that the higher the wind speed is, the worse the dust removal efficiency is. The numerical simulation results show that the simulation method is reliable and can provide the basis for the design and renovation of the electrostatic precipitator. At the same time, it is proved that the oblique airflow technology is more helpful to improve the efficiency of electric dust collection.
【学位授予单位】：东北电力大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X701.2

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