【作者】 王升贵；

【导师】 陈文梅；

【作者基本信息】 四川大学 ， 化工过程机械， 2006， 硕士

【摘要】 深入理解水力旋流器内流体动力学实质,准确认识其分离机理,才能对其进行正确的设计。但是,由于以往的研究只考虑旋流器内分离过程的确定性因素,忽略了其随机因素,因此以往的研究结果不够准确,并且通用性较差。在本研究中综合考虑影响旋流器内分离过程的各种因素,采用数值模拟和实验验证与理论分析相结合的方法,系统研究了水力旋流器内分离过程的随机特性,较完整地认识了其分离机理。采用高精度的计算流体力学软件FLUENT 6.1对水力旋流器内的流体流场、流动结构和颗粒的运动过程进行了系统的数值模拟,分析了三维速度分布、压力分布、流体流动结构、空气核(又叫空气柱)以及颗粒运动的轨迹、进料口位置对分离过程的影响和颗粒粒度对分离效率的影响。结果表明:水力旋流器内流场具有不对称性,这种不对称主要是由于不对称的进料位置以及旋流器内流体流场的强烈湍动、空气核不规则的形状以及径向强烈偏摆等因素造成的。同时,在旋流器内随机分布着形状和大小不相同的各种形式的涡团,严重影响了流场的稳定性,因此旋流器内流场表现出强烈的随机特性;模拟计算结果显示出空气核直径除与溢流口直径、底流口直径、锥角、给入压力有关外,还与所处轴向位置有关;单个颗粒在旋流器内的运动轨迹是随机的,对单个颗粒运动而言,其受力系统非常复杂,其在运动过程中所受的确定性和随机性作用同样重要;还系统分析了进料位置对分离过程的影响。在本研究中首次利用先进的高速摄象技术,实测了固体颗粒在旋流器内的运动过程,并获得了颗粒的准确运动轨迹,进而分析了颗粒在旋流器中的运动规律。实测研究结果证明了单个颗粒在旋流器内运动轨迹的随机性,颗粒在旋流器内的运动形态可以分为颗粒的外螺旋运动、内螺旋运动、短路流运动、衍更多还原

【Abstract】 The optimum design of structure of hydrocyclones need deeply and exactly understanding the essential of fluid flow dynamics and the separation mechanism of hydrocyclones. However, the previous investigations only considered determinate factors, and ignored the stochastic factors. So the conclusions were inaccurate and unsatisfied. In this study, comprehensively considered factors effecting on the separation process, the stochastic characteristics of the separation process inside hydrocyclones was investigated systemically using numerical simulation and validated by experiment.Flow field, flow structure and movement of particles inside hydrocyclones were simulated systemically by a high-precise software named FLUENT 6.1. The velocity distribution, pressure distribution, flow structure, air core, movement tracks of particles, effect of location of particle entrance on separation process and influence of particles size on separation efficiency were analyzed. The results showed that the flow field inside hydrocyclones was asymmetric. The factors that caused this asymmetry were asymmetric feeding location, strong turbulence of fluid flow, irregular form and radial fluctuating violently of air core. Eddies with different forms and sizes which distribute randomly within hydrocyclones have affected the stability of flow field. Therefore, the flow field had stochastic characteristics; The results of numerical simulation indicated that the diameter of air core depended not only on diameters of overflow and underflow orifices, cone angle and pressure, but also on its axial position; Movement track of single particle inside hydrocyclones was randomly. For single particle, forces acting on it are very complex, the determinate and stochastic effects were both important. The effects of location of particle entrance on separation process were also analyzed systematically.The moving process of particles inside hydrocyclones were observed using advanced KODAK EKTAPRO HS Motion Analyzer for the first time. The moving traces of partices were obtained and the motion behavior were further analyzed.The results testified that movement track of single particle inside hydrocyclones was stochastic.From above investigations,we discovered that the moving forms of更多还原