除油水力旋流器内油水分离过程数值模拟

采用计算流体力学的有限体积法(FVM),对液-液水力旋流器的轻相分离过程进行了非稳态的数值计算,得到了油相在旋流器内的逐渐分离、聚积和运移的过程。进一步分析发现,该旋流器的小锥段分离作用突出,而大锥段和旋流腔的分离作用较小,但大锥段具有重要的过渡作用。     

液液水力旋流器流场特性与分离特性研究(六)——结构参数对分离特性的影响

对液液水力旋流器主要结构参数 ,如旋流腔长度、锥段长度等分离特性影响因素进行了分析 ,并针对普通油水混合液和含聚合物的油水混合液分别进行了研究。     

液液水力旋流器流场特性与分离特性研究 (一)——锥角变化对切向速度场的影响

研究了液液水力旋流器锥角变化对其切向速度场分布的影响，主要讨论了大、小锥角变化时大锥段和小锥段速度场的分布情况，得出了一些有益的结论     

大锥段注气对液-液水力旋流器分离性能的影响

针对油田含聚污水处理难度大的问题,利用CFD和多孔介质模型建立了旋流器内部流体的计算模型,数值模拟分析了大锥段注气旋流器内多相流体速度场和压力场的分布规律,结果表明:大锥段注气后,在旋流区和大锥段区的径向速度和流向溢流口的轴向速度明显提高,分离性能有所改善;产生的气浮选效应使混合液的分离难度降低,压力降减小,节约了能源。提出旋流器流场分界区的概念,研究表明在分界区注气能更好地改善分离效果,分界区的位置取决于旋流器的结构参数和操作参数。     

液液水力旋流器流场特性与分离特性研究(二)——锥角变化对轴向速度场的影响

研究了液液水力旋流器锥角变化对其轴向速度场分布的影响， 主要讨论了大、小锥角变化时大锥段和小锥段轴向速度场的分布情况，得出了一些有益的结论。     

液液水力旋流器流场特性与分离特性研究（二）——锥角变化对轴向速度 …

研究了液液水力旋流器锥角变化对其轴向速度场分布的影响，主要讨论了大、小锥角变化时大锥段和小锥段轴向速度场的分布情况，得出了一些有益的结论。     

液液水力旋流器场特性与分离特性研究（一）：锥角变化对切向速度场 …

研究了液液水力旋流器锥角变化对其切向速度场分布的影响，主要讨论了大、小锥角变化时大锥段和小锻段速度场的分布情况，得出了一些有益的结论。     

水力旋流器结构与分离性能研究（三）：锥段结构

研究了水力旋流器锥段结构开关肥及锥段体积对其分离性能的影响，结果表明：采用螺旋型锥段结构时水力旋流器处理能力最高；采用抛物线型锥段结构时水力旋流器的分离修正总效率最高，分离精度最高，分流比最小；采用普通型光滑直锥时旋流器分离粒度最小，随着光滑内壁型锥段体积的增大，旋流器分离修正总效率呈线性提高，而旋流器分流比则呈线性下降。     

水力旋流器分离性能强化研究

设计了一种在旋流器轴心线位置具有中心固棒的新型水力旋流器,该中心固棒的引入有效地消除了旋流器内的中心空气柱。实验研究了该中心固棒替代空气柱对旋流器性能指标的系统影响。研究结果表明,采用中心固体棒取消旋流器内的空气柱后,旋流器的分离性能得到了有效的强化。与具有空气柱的旋流器相比,不管旋流器锥段结构如何变化(从普通直锥、到抛物线型锥、到双曲线型锥),具有中心固棒的旋流器均具有更高的分离总效率、更高的修正分离总效率、更小的修正分离粒度以及更高的分离精度。随着旋流器锥段内部空间的增大,中心固棒使旋流器分离性能提高的幅度也增大。     

液液旋流器中粒径、流量和效率的关系

在固液旋流器中 ,流量和粒径被孤立地看作是影响分离的两个参数。本文以除油旋流器的实验结果为基础 ,阐述了液液水力旋流器中流量的作用机理 ,以及液滴和流量之间的联系 ,综合分析了粒径和流量对分离的影响 ,定性地给出了液液水力旋流器的粒径 -流量 -效率曲线 ,并为液液旋流器的深入研究提供了新思路     

Study of the Performance of a Novel Hydrocyclone Built in the Configurations of the Classical Families

The performance of classical families of hydrocyclones (Bradley, Rietema, and Demco) has been compared with a novel equipment, the filtering of hydrocyclones. In the filtering of hydrocyclones, the conical section is replaced by a conical filtering wall producing another liquid stream leaving the equipment besides underflow and overflow streams. In the present paper, the influence of the filtering conical wall in the classical geometries was analyzed by experimental and CFD studies. The results showed that the replacement of the conical section of hydrocyclones built with classical geometries by a filtering cone have significantly changed their performance. In general, the separation performance and the capacity can be enhanced with the filtering hydrocyclones.     

Improvement of hydrocyclone separation performance by incorporating a conical filtering wall

In this work, the performances of conventional hydrocyclones have been compared with a new configuration, known as filtering hydrocyclone. This non-conventional solid–liquid separator consists of a hydrocyclone whose conical section is replaced by a conical filtering wall. Thus, during the operation of these devices, besides the underflow and overflow streams, there is another stream of liquid, resulting from the filtrate produced in the porous cone. The experimental and CFD results, obtained in 25 different configurations of both conventional and filtering hydrocyclones, show that the performance of hydrocyclones is significantly influenced by the replacement of the conical section of the conventional device by a conical filtering wall. The separation performance and the capacity can be enhanced with the filtering hydrocyclones, as compared with similar conventional.     

除油旋流器入口流量与基本性能的关系研究

对除油旋流器边壁的油滴粒径变化、旋流器的分离效率以及压力降与入口流量之间的关系进行了研究。结果表明 ,当入口流量达到一定程度时 ,旋流器边壁的平均粒径随入口流量的增加而降低 ,分离效率随入口流量的增加而增加。整个旋流器以及旋流器各段的压力降均与入口流量成指数关系 ,都随入口流量的增加而增加。在旋流器的压力损失中 ,进口、旋流腔及大锥段所占比例最大 ,且基本不随入口流量的变化而变化 ;小锥段次之 ,并随入口流量的增大而增大 ;直管段的压力损失所占的比例最小 ,它随入口流量的增大而不断降低。     

Design and Numerical Simulation Analysis of an Integrative Gas‐Liquid‐Solid Separation Hydrocyclone

Normally, a gas‐liquid‐solid separation includes both degassing and desanding processes, which means a relatively higher facility investment and larger energy consumption. Based on an inner‐cone hydrocyclone developed before, an integrative degassing and desanding hydrocyclone was designed. Its design idea and process are described in detail. By means of a hollow inner cone (IC), the separated liquid enters into the cone through holes on it and then flows to the liquid‐phase outlet. Due to integrative separation and tangential solid outlet, the separator has a more compact size. Simulation analysis of the effect of IC diameter and IC height on separation performance was carried out. Results indicate that with a larger IC diameter the gas content in the solid outlet decreases, while as the IC height rises, the gas content in the liquid outlet increases.     

防返混锥对旋风除尘器内二次流的抑制效果研究

旋风除尘器下部灰斗内存在的二次流会引起被捕集颗粒重新进入气流,进而导致旋风除尘器除尘效率下降。为有效抑制灰斗内二次流,采用内置防返混锥的手段,对不同防返混锥几何尺寸与安装位置的旋风除尘器进行两相流数值模拟。结果表明,内置防返混锥减少了灰斗内流场的切向、轴向速度及湍流强度,对旋风除尘器灰斗内二次流所引起的颗粒返混现象有显著的抑制作用。模拟结果推荐防返混锥最佳几何尺寸的顶角角度为80°,最佳安装位置为底面与锥口的垂直距离0.375B≤Bs≤0.5B。在入口速度为12 m/s时,与原结构相比,总除尘效率提高11.50%,压降增加8.29%。     

基于旋转分相单元的电容式气液两相流含液率测量

为提高电容器对含水率测量的能力,设计与其相匹配的旋转分相单元,以实现气液两相流含水率的起旋分相式电容测量。在电容传感器的测量单元基础上,增加旋转分相单元,利用气液两相流体力学理论对其结构进行设计优化,并根据实际应用条件确定分离圈数,保证气液分相效率。旋转分相单元克服了气液两相流流动形态的多样性,将体积含水率信息转换成液膜厚度信息及截面含水率信息进行测量。经实验验证,Lockhart-Martinelli截面含气率模型与实验中电容器测量截面含气率具有良好的一致性,其能够实现对体积含水率20%以内的气液两相流有效测量,体积含水率的绝对误差在±2%以内。     

基于离散相模型的双锥型水力旋流器磨蚀分析

基于计算流体动力学(CFD)方法,采用Gambit建模,利用Fluent软件中的离散相模型(DPM)进行分析,分析出了普通双锥型水力旋流器内壁的磨损部位包括切向入口处、旋流腔和大锥段的交界处,以及大锥与小锥的交界处等;改进后旋流器的磨损情况得到了明显的改善,分离效率也有所提高。同时,对双锥型水力旋流器的压力特性进行了分析。     

Effect of the ethylene content of poly(ethylene-co-vinyl alcohol) on the formation of microporous membranes via thermally induced phase separation

Porous poly(ethylene-co-vinyl alcohol) (EVOH) membranes were prepared via thermally induced phase separation. The effect of the EVOH ethylene content on the membrane morphology and solute rejection property was investigated. For EVOHs with ethylene contents of 27–44 mol %, polymer crystallization (solid–liquid phase separation) occurred, and the membrane morphology was the particulate structure. However, the liquid–liquid phase separation occurred before crystallization for EVOH with a 60 mol % ethylene content. Cellular pores were formed in this membrane. For the particulate membranes, higher solute rejection and lower water permeance were obtained for EVOH with a lower ethylene content. The membrane formed by the liquid–liquid phase separation showed a sharper solute rejection change with a change in the solute radius than the particulate membranes did. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2583–2589, 2001     

分相式多孔壁微通道流动冷凝传热强化与减阻

微通道换热器应用广泛,强化传热和减阻是新型换热器设计的重要目标。为了同时实现这两相目标,本文提出了一种分相式多孔壁微通道冷凝器,利用微针肋阵列组成的多孔壁在冷凝传热过程中实现了汽液两相分离。采用实验研究方法对比了分相式多孔壁微通道与普通实心壁微通道的流动和传热特性,结果证明分相式微通道在冷凝传热中同时具备强化传热和减阻的作用。深入研究了通道内两相流动摩擦耗散原理并提出了相分离减阻理论,指出汽液两相流内部摩擦耗散的减小是分相流减阻的关键。另一方面,分相过程使针肋换热面侧壁直接与高温蒸汽接触,极大消减了蒸汽与换热壁面之间的传热液膜厚度。沿流动方向不断扩展的液通道截面与不断减缩的汽通道截面积适应了流动冷凝过程延工质流动方向"水渐多,汽渐少"的规律,保证沿程传热效果不会恶化。     

Non-Steady-State Convective Diffusion in a One-Dimensional Closed Loop

Non-steady-state convective diffusion in a closed loop with a constant cross section and in a circuit containing a section with a different cross section and a piston flow regime of the circulating flow has been analyzed. The simple analytical dependences that describe the tracer concentration in an inlet cross section from the first recirculation cycle to an arbitrary nth cycle have been obtained. The analytical dependences for simulating chromatographic separation in a closed liquid–liquid loop have been obtained. It has been shown that, unlike conventional chromatographic methods, in recirculation chromatography, the efficiency of the separation can be improved by lengthening the connecting lines.