大长径比直筒型旋风分离器内部流动特性研究  

Flow Characteristics in a Cylindrical Cyclone Separator with Large Length to Diameter Ratio

作　　者：高助威 王娟[1,2] 王江云 马卓越[1,2] 毛羽 GAO Zhu-wei;WANG Juan;WANG Jiang-yun;MA Zhuo-yue;MAO Yu(State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China;Beijing Key Laboratory of Process Fluid Filtration and Separation, Beijing 102249, China)

机构地区：[1]中国石油大学重质油国家重点实验室,北京102249 [2]过程流体过滤与分离技术北京市重点实验室,北京102249

出　　处：《高校化学工程学报》2018年第6期1288-1298,共11页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金(21106181);中国石油大学(北京)科研基金(2462015YQ0303)

摘　　要：为了探究大长径比直筒型旋风分离器内部的流动特性,采用雷诺应力模型(RSM)对单入口蜗壳式旋风分离器进行数值模拟,从瞬态流场和动态特性两个方面分析不同轴向位置的切向速度分布。同时,运用RMS分析了湍流脉动速度偏离时均速度的程度。结果表明,在瞬态流场中,切向速度等值线在截面上分布不对称,呈现明显的非轴对称现象;主要表现为切向速度零值的所在位置与几何中心不重合,零值偏移的一侧,切向速度较大,偏离的一侧较小。此外,切向速度的动态变化属于高速脉动状态,具有准周期性特点,通过优化结构或操作条件可以改变涡核频率,降低工业震动。在分离空间上部区域,流动不稳定性较大,湍流脉动较强,速度波动范围较大。随着轴向向下,流体能量逐渐耗散,速度脉动逐渐减小。RMS数据表明运动流体从入口段进入旋风分离器,流动不稳定性逐渐增大,达到一定程度后,不稳定性逐渐变小,直至较为平稳。Numerical simulation of gas flow in cylindrical cyclone separators was studied using Reynolds stress model(RSM)to investigate flow characteristics in a cylindrical cyclone separator with large length-to-diameter ratio.Tangential velocity distribution at different axial sections was analyzed by transient flow field and dynamic performance evaluation.Meanwhile,RMS was used to identify deviation degree of turbulent velocity from time-average velocity.The results demonstrate that the tangential velocity of transient flow shows a non-axisymmetric phenomenon at cross sections,which is mainly presented as asymmetric distribution of contours.The location of tangential velocity=0does not overlap with the geometric center,and the tangential velocity is larger near the zero location.In addition,the dynamic characteristics of the tangential velocity show high-speed pulsating with quasi-periodic characteristics.Structure and operation optimization can change core frequency and reduce industrial vibration.In the upper part of the cylinder,flow instability is more obvious,and turbulent pulsation is strong with high velocity fluctuation.Fluid energy gradually dissipates and pulse speed gradually reduces when moving downward.RMS data shows that flow instability gradually increases from inlet,which then decreases and becomes stable.

关 键 词：直筒型风分离器 大长径比 数值模拟 动态特性 旋流不稳定性 

分 类 号：TQ051.8[化学工程]