沉箱式柱状旋流气液分离器的分离性能研究

发布时间：2018-11-03 21:19

【摘要】：沉箱式柱状旋流分离器是一种拟应用在海底的分离器,兼顾两相和三相分离功能。本文着重研究其两相分离功能,以入口管下倾预分离、柱状旋流主分离、卧式沉箱重力辅助分离的分离机制进行分离器的设计;以多相旋流分离理论为指导,以数值模拟与试验测试为手段,对分离器主分离区流场分布特点及结构影响因素进行了深入分析。主要研究内容与结论如下:分离器主分离区的模拟研究表明切向速度呈现兰金组合涡结构特征,轴向速度整体呈现“倒V”型分布,总压分布呈中心低、壁面附近高的特点;在各结构参数的模拟尺寸范围内,增加入口管下倾角度、筒体上部高度、排气管直径会降低分离器的压力损失,但同时会引起切向速度和轴向速度的衰减,降低旋流强度,而且增加排气管直径会使轴向速度由“倒V”型分布转变为“M”型分布,产生滞流;筒体直径和排气管插入长度的增加既会使压力损失升高,也会引起旋流强度的降低。分离器单向入口的非轴对称性使分离筒体空间的流场呈现不稳定性,表现为旋转中心偏离分离筒体的几何中心。研究表明,在各结构参数的模拟尺寸范围内,增加入口管下倾角度、减小筒体直径和排气管直径会使分离器内部流场的不稳定特性增强;排气管插入分离器内部会改善分离器的流场不稳定性;而筒体上部高度的变化对流场不稳定性没有明显的影响。沉箱式柱状旋流分离器的室内样机性能测试试验表明:在试验工况范围内,气、液相流量的增加增强了旋流强度,但同时会引起分离器内壁液膜的附着及爬升,而气相流量的增加是主要因素,其沿壁面旋转产生的巨大剪切曳力使液滴克服自身重力和剪切阻力随气流沿壁面爬升形成液膜;入口管下倾有利于入口管中分层流的形成,而且会降低流体在筒体入口以上的旋流高度,减少气相的液体携带;增加分离器筒体上部的柱体高度,可以扩展分离器的高效运行范围,提高分离器的分离性能;排气管插入长度对分离器高效运行区的影响不如筒体上部高度改变所带来的影响大。
[Abstract]:The caisson type cylindrical cyclone separator is a kind of separator which is to be used on the sea floor and has the function of two-phase and three-phase separation. In this paper, the function of two-phase separation is mainly studied. The separator is designed by the separation mechanism of inlet tube downdip preseparation, columnar swirl main separation and horizontal caisson gravity assisted separation. Under the guidance of multi-phase swirl separation theory and by means of numerical simulation and experimental test, the characteristics of flow field distribution and structural factors in the main separation zone of the separator are analyzed in depth. The main research contents and conclusions are as follows: the simulation of the main separation zone of the separator shows that the tangential velocity presents the characteristics of Lanjin combined vortex structure, the axial velocity presents the "inverted V" type distribution, the total pressure distribution is low in the center and the wall surface is high; In the range of simulated dimensions of each structural parameter, increasing the downdip angle of the inlet tube, the height of the upper cylinder, and the diameter of the exhaust pipe will reduce the pressure loss of the separator, but at the same time, it will cause the attenuation of tangential and axial velocity and decrease the swirl intensity. Moreover, increasing the diameter of exhaust pipe will change the axial velocity from "inverted V" to "M", resulting in stagflation. The increase of cylinder diameter and exhaust pipe insertion length will not only increase the pressure loss, but also cause the decrease of swirl intensity. The non-axisymmetric property of the unidirectional inlet of the separator makes the flow field of the separation cylinder unsteady and the rotating center deviates from the geometric center of the separation cylinder. The results show that increasing the downdip angle of the inlet tube and decreasing the diameter of the cylinder and the exhaust pipe will enhance the unstable characteristics of the internal flow field of the separator in the range of the simulated size of the structural parameters. The flow field instability of the separator can be improved by inserting the exhaust pipe into the separator, but the instability of the flow field is not obviously affected by the change of the height of the upper part of the cylinder. The performance test of the indoor prototype of the caisson type cylindrical cyclone separator shows that the increase of the flow rate of gas and liquid increases the intensity of the swirl flow, but at the same time it will cause the adhesion and climbing of the liquid membrane in the inner wall of the separator. The increase of gas flow rate is the main factor, and the huge shear drag caused by rotating along the wall makes the droplets overcome their own gravity and shear resistance to climb along the wall to form a liquid film. The downdip of the inlet tube is beneficial to the formation of the stratified flow in the inlet tube, and it will reduce the swirl height of the fluid above the inlet of the cylinder and reduce the liquid carrying in the gas phase. Increasing the cylinder height of the upper part of the separator can expand the high efficiency operation range of the separator and improve the separation performance of the separator. The influence of the exhaust pipe insertion length on the high efficiency operation area of the separator is not as great as the change of the height of the upper cylinder.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE95

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