旋风除尘器优化设计及分离特性研究

【作者】 李强；

【导师】 曹中一；

【作者基本信息】 中南大学 ， 机械设计及理论， 2008， 硕士

【摘要】 旋风除尘器作为一种重要的气固分离设备,因其结构简单、设备紧凑、制造容易、成本相对较低等优点,被广泛应用于矿山、化工、能源、环保、冶金、建材等众多工业领域。然而往往因其结构设计不当,尺寸匹配不合理等因素限制了除尘效率的提高,并且能耗很大。当前,随着国民经济的不断增长及“节能减排”战略的适时提出,在工业生产中,迫切需要研制高效率低能耗的新型旋风除尘器。为此,本文针对旋风除尘器传统设计方法不够完善,通用性差及其内部三维流场规律认识不全面等问题,采用优化设计和数值模拟相结合的研究方法,首先基于经典的Leith-Licht边界层分离理论,建立了旋风除尘器优化设计数学模型,并借助MATLAB工具得出了设计工况下的结构尺寸;然后以优化出的旋风除尘器为研究对象,通过商业软件FLUENT,采用基于各向异性的RSM雷诺应力模型、QUICK差分格式、PRESTO压力插补格式和SIMPLEC算法对其内部气相流场进行了数值模拟,成功地模拟出旋风除尘器内部的双层旋流结构,并获得了较理想的速度—压力场预报结果;接着在气相流场模拟的基础上,利用相间耦合的DPM离散相模型对旋风除尘器内部的固相颗粒进行了数值模拟研究,考察分析了不同情况下的颗粒运动轨迹及不同入口颗粒浓度、不同排气管插入深度、不同排气管直径、不同排灰口直径和不同直管长度等操作与结构参数对分离性能的影响;最后,基于上述的数值模拟结果,有效地预测了优化型旋风除尘器结构尺寸匹配的合理性及提出的优化设计方法的可行性,从而为今后旋风除尘器的研制提供了一种通用的设计方法。本文在旋风除尘器优化设计和内部流场数值模拟等方面取得的研究成果,不但能更好地反映操作参数、结构参数对其分离性能的影响,又能为进一步优化旋风除尘器的结构提供有意义的参考。因此本文的研究无论是在工程应用,还是在理论研究方面上都具有十分重要的价值。更多还原

【Abstract】 Cyclone separator is an important gas-solid separation equipment, which has many advantages, such as simple structure, compact equipment, easy to manufacture, relatively low-cost and so on. So it has been widely applied in the mining, chemical industry, energy source, environmental protection, metallurgy, building materials and the other industrial fields. However, because of unreasonable structure design and size matching factors, which restrict the efficiency improving, besides it wastes more energy consumption.At present, with the continuous growth of the national economy and the energy-saving reduction strategy proposed timely, people urgently need to research a new type cyclone separator that has much higher separation efficiency and lower consumption. Therefore, in view of the unperfect separation model and the weak prevalence of the traditional design method. In addition, people can’t understand accurately the separation theories of cyclone separator. Using numerical simulation and optimal design combination of research methods, first of all, the thesis constructs an optimal mathematics model based on the classic Leith-Licht boundary layer separation theory, and then gains the configuration size under the design condition by the optimal function of MATLAB. Secondly, based on the anisotropy of RSM model, QUICK format, PRESTO format and SIMPLEC arithmetic, the thesis not only successfully simulates the double layers vortex flow structure of gas field, but also acquires the more ideal forecast results of the velocity and pressure field of the optimal cyclone separator by the commercial software FLUENT. And then based on the simulation of gas flow field, to simulate the inner solid phase of cyclone separator by two-phase fluid coupling of dispersed particle model (DPM), inspect the movement tracks of particles under different circumstances, and research the separation performance from the influence of different operating parameters and structural parameters. For example, different inlet particle concentration, different insert depth and diameter of riser, different vent diameter and different vertical tube length of cyclone separator. At last, based on the results of 3D flow field numerical simulation, prove the rationality of the size match and the feasibility of the design optimization and propose a universal design method for the future provision of cyclone separator.In the thesis, the study on optimal design and numerical simulation of cyclone separator can not only reflect the influence of configuration and operation parameters, but also provide reference for configuration optimization of cyclone separator. Therefore, it has significant application value in the engineering application and theoretical research.更多还原