基于M模型的低密度物料旋风分离器分离性能研究

【作者】 邓清方；

【导师】 张怀亮；

【作者基本信息】 中南大学 ， 机械制造及自动化， 2011， 硕士

【摘要】 旋风分离器作为一种重要的气固分离设备,因其具有结构简单、维护方便、造价低、耐高温高压等优点,在石油、化工、冶金、环保等许多领域有着广泛的应用。使得旋风分离器的研究越来越受到重视。本文的主要工作是利用Muschelknautz模型(M模型),计算用于低密度物料生产的旋风分离器,得到该旋风分离器的结构尺寸、切割粒径和总压降。同时利用流体力学软件FLUENT对所设计的分离设备进行了数值模拟。研究了纯气相流场、气固两相流场两种情况下的速度变化和浓度变化对分离效率的影响。研究结果表明：旋风分离器内的气相主流是双层旋流,外部是向下旋转的外旋流,中心是向上旋转的内旋流,它们的旋转方向相同的；旋风分离器中旋涡具有不稳定性,它会引起旋风尾部附着在旋风分离器下部壁面并旋转摆动,使得返混现象变严重,同时还会引起结垢现象；旋风分离器的静压力、各方向速度和固体颗粒分离率都随处理气量的增大而增大,流体呈漩涡状沿器壁旋转向下,外旋流的压强较高,内旋流的压强较低,分离器中心处的静压最低,固体颗粒集中分布在中间段的器壁上；随着气体中颗粒浓度的增大,分离总效率及分级效率都逐渐增大,当浓度达到某一定值时,各种粒径颗粒的分离效率都会趋于稳定；M模型预测结果与数值模拟结果非常接近,说明采用M模型对低密度物料旋风分离器进行预测具有较好的准确性。本文为M模型在低密度物料旋风分离器中的应用研究提出了新思路。同时,通过对旋风分离器的数值模拟,可以优化旋风分离器的结构,大大缩短研发周期,具有重要的工程应用价值。更多还原

【Abstract】 As important gas-solid separation equipment, due to the advantages such as simple structure, easy maintenance, low cost, high temperature resistant and high pressure resistant, cyclone separator is applied in wide range areas of petroleum, chemical, metallurgical,environmental protection and many other fields, and the research of which is attracting increasing attention.The main works are that cyclone separator for the low density of material production is calculated with Muschelknautz model (M-model), and its structure size, cut size and total pressure drop are obtained. At the same time numerically simulation is carried on for separator through computer’s fluid software FLUENT. The simulation research is deal with that influence of change in pressure, velocity and density change for eddy current characteristics and separation efficiency by pure gas phase flow field and gas-solid two-phase flow field. Thus it is shown that The motion characteristics of gas phase flow field of the cyclone separator inner is double hydro-cyclone mainly, where outer part rotate downward, center layer upward and rotation direction is same; Cyclone separator’s swirl with instability result in vortex core tail or ends attached at separator bottom wall and swings, causes reflux of mixing phenomenon, and causes scale formation; Cyclone separator’s static pressure, speed of each direction and separation efficiency of solid particle increases with increase of handled gas. Flow with is swirling along the wall downward, pressure of the outer part is high, the pressure of center is low, the solid particles are concentrated distribution in the middle wall section mainly; With increase of particle concentration in gas, separating efficiency increase gradually. While the concentration increases to a certain amount that is a threshold, separation efficiency of particle wouldn’t increase again, and come to stability; Predicted result of M-model is approaching to numerical simulation result, which demonstrates the forecast for low density of material cyclone separator with M-model has good accuracy.This article provides new ideas for application and research of low density material cyclone separator with M-model. At the same time, numerical simulation study is carried on for cyclone separator, thus characteristic of separator internal flow field is known, and there is important engineering application value for structure optimizing of the separator, shorten research and development cycle.更多还原