超音速气雾化喷头结构设计及数值模拟

发布时间：2018-05-19 02:04

本文选题：煤矿除尘装置 + 超音速气流　；参考：《安徽理工大学》2017年硕士论文

【摘要】：粉尘是煤矿井下主要自然灾害之一,其不仅影响矿井下的工作环境,且在一定条件下会发生爆炸,严重威胁矿井生产安全和工作人员身心健康。随着矿井机械化水平的不断提高,井下粉尘量也越来越大,一套合理、有效的除尘装置变得极为迫切。本文以超音速气雾化喷头为研究对象,利用工作面管网中的压风和压水,通过喷头形成气雾捕捉粉尘,可以有效的降低煤矿井下粉尘颗粒浓度,净化空气质量,杜绝了粉尘爆炸事故的发生。其主要研究内容如下:1.以二维平面为计算域,不考虑气流压缩性和喷管结构的影响,在不同超音速横风下对液柱一次雾化、液滴二次雾化和激波雾化机理进行数值模拟分析。2.根据对雾化机理和拟一维喷管流动解析解,设计拉瓦尔喷管结构曲线以及三种不同液膜环缝的形状、位置的内喷管,建立超音速气雾化喷头三维模型。3.考虑气流的压缩性,对超音速气雾化喷头内喷管气流加速特性研究,通过数值计算软件Fluent对超音速气雾化喷头二维模型气-液两相雾化和三维模型工.作环境下气雾化流场的模拟验证。根据液柱一次雾化模拟结果,得到液柱横风下雾化粒度状态和穿透深度动态图,并拟合得到横风速度与液柱直径对穿透深度的经验公式;根据液滴横风下的二次雾过程的可视化模拟结果,解释了液滴从表层液的蠕动、变形到完全破碎为二次液滴的物理原因;尝试激波脉冲作用下对液滴的的雾化模拟;对所设计内喷管模拟得到气流加速特征曲线,并通过气-液两相紧耦合VOF+Level Set模型模拟,得到内喷管压力、速度、湍流强度等分布云图;对超音速气雾化喷头三维模型除尘工况模拟,得到气雾卷吸污风的三维流场。
[Abstract]:Dust is one of the main natural disasters in the coal mine. It not only affects the working environment under the mine, but also explodes under certain conditions, which seriously threatens the safety of mine production and the physical and mental health of the workers. With the improvement of mine mechanization, the amount of dust is increasing, and a reasonable and effective dedusting device is becoming more and more urgent. In this paper, the supersonic gas atomization nozzle is taken as the research object, the dust can be effectively reduced and the air quality can be purified by using the pressurized air and water pressure in the working face pipe network to form the air mist to capture the dust in the coal mine. Put an end to the dust explosion accident. The main research contents are as follows: 1: 1. Taking the two-dimensional plane as the computational domain, the mechanism of the primary atomization of liquid column, the secondary atomization of droplet and the atomization mechanism of shock wave are numerically simulated under different supersonic transverse wind without considering the compressibility of airflow and the structure of nozzle. According to the atomization mechanism and the analytical solution of quasi-one-dimensional nozzle flow, the structure curve of Laval nozzle and the inner nozzle with three different liquid film annular seams are designed, and the three-dimensional model of supersonic atomization nozzle .3is established. Considering the compressibility of the airflow, the acceleration characteristics of the nozzle in the supersonic gas atomization nozzle are studied. The two-dimensional gas-liquid two-phase atomization and the three-dimensional modeler of the supersonic gas atomizer are simulated by the numerical calculation software Fluent. The simulation of the gas atomization flow field in the environment is carried out. According to the results of one-time atomization simulation of liquid column, the dynamic diagram of atomization particle size and penetration depth under crosswind is obtained, and the empirical formula of crosswind velocity and liquid column diameter to penetration depth is obtained. According to the visual simulation results of the secondary fog process under the cross wind of the droplet, the physical reason of the droplet's creep from the surface liquid to the complete break-up to the secondary droplet is explained, and the atomization simulation of the droplet under the action of shock pulse is attempted. The characteristic curve of airflow acceleration was obtained by simulating the designed nozzle, and the distribution of pressure, velocity and turbulence intensity of the nozzle was obtained by the VOF Level Set model of gas-liquid two-phase tight coupling. The three dimensional model of supersonic atomization nozzle was simulated, and the three dimensional flow field of air mist entrainment was obtained.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD714.4

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