Branch Quality Control of Gas-Liquid Two-Phase Flow Using a Novel T-Junction Type Distributor

In order to eliminate mal-distribution and ensure the side arm to produce desirable gas quality a special distributor is proposed. The experimental distributor mainly consists of a straight through section,a gas extraction line,a liquid extraction line and a side arm branch. A gas orifice and a liquid orifice are mounted at the gas and liquid extraction line respectively to control the outlet gas quality. The diameter of the liquid orifice was set to 2. 50 mm and three gas orifices with different size( dG= 2. 65,5. 00,10. 00 mm) were tested. The experiments were carried out at an air-water two-phase flow loop. The gas superficial velocity ranged from 6. 0 to 20. 0 m /s and the liquid superficial velocity was in the range of 0. 02- 0. 18 m /s. Flow patterns such as wave flow,slug flow and annular flow were observed. The gas quality of the side arm branch was found mainly determined by the flow area ratio of the gas orifice to the liquid orifice and independent of gas and liquid superficial velocity,flow patterns and extraction flux.

FLUID DYNAMICS IN A GAS-STIRRED LADLE——A Separated Flow Model with Stochastical Trajectories

A separated flow model with stochastical trajectories has been developed to describe the fluid flow in a bubble stirred ladle.The bubble dispersion,turbulent characteristics and gas-liquid interactions can be predicted by this mathematical model.The bubble flow as a dispersed phase is treated in a Lagrangian frame of reference and the analysis of the turbulent flow for liquid phase is conducted in a Eulerian field.The interactions between bubbles and liquid phases are considered as a bubble source term in the control equation for a continuous phase. The Monte Carlo sampling method is used to determine the bubble trajectories.The homoge- neous flow model is also taken into consideration so that it can be compared with the sepa- rated flow model.Numerical predictions using a water model of a ladle show that the pre- dicted results of the separated flow model agree satisfactorily with the experimental results, but the prediction of the homogeneous flow model are not in good agreement with the experi- mental results.

数字式分层注水流动特性研究与分析

针对长庆低渗透油藏精细分层注水特点,常规分注技术存在实时监控难以及测调过程复杂等问题,提出了数字式分层注水技术。该技术应用配水器集成孔板流量计、一体化可调水嘴、电机、验封短节、井下电源、通信模块及控制芯片等部件,实现了配水器的自动验封、自动调节、数据实时录取与存储和无线通信的功能,极大地提高了注水过程的自动化水平。通过分析油管的沿程流阻、水嘴和流量计的阻力损失,建立了数字式分层注水井注水的流动特性分析力学模型。利用该模型可以计算得出井下各层的注水压力及水嘴开度关系,进而优化注水参数,提高分层注水效果。

新型抽吸型气-液分流式分布器的性能

开发了一种新型气-液分流式分布器,采用冷模实验装置考察了气体操作线速度和液体线速度分别在0~6.19cm/s和0.18~0.44cm/s范围时分布器安装高度差对液体分布的影响,并与工业上使用的泡罩式分布器对比。结果表明,由于气-液经由独立的通道,有着恒定的流通面积,气-液分流式分布器对塔板倾斜的敏感度较低,且随气速的增大不断减小;当气体线速度超过3cm/s、气/液流量比大于10时,该分布器分布不均匀度可降至10%,接近均匀分布。采用计算流体力学软件模拟了单个分布器抽吸过程,得到各相体积分数和速度分布等值线等流场结构。

新型投捞式恒流配水器设计与应用

针对偏心配水器存在的问题及中原油田大斜度井分层注水效果差的问题,研制了投捞式恒流配水器。采用固定和活动水嘴双级水嘴节流模型,利用碟簧减少压力波动,使流量保持恒定,实现了带水嘴坐封分注管柱,提高了分注成功率,满足了多级分层开发。现场应用表明,使用该配水器可减少投捞次数,提高注水时效;在工况变化的情况下实现恒流注水;洗井时间比原来缩短1/2,洗井液用量减少50%,成功率100%。

多相流的取样式计量技术

对多相流计量方法进行归类，主要对近年来多相流的取样式计量技术的研究进展进行了回顾总结，从而提出存在问题和发展方向。

新型管槽式吸收塔液体分布器的研制及性能测试

针对气体吸收分离中常见的吸收塔管式、槽式分布器液体分布不均匀的问题,开发出一种新型的管槽式液体分布器,并搭建直径1.2 m的吸收塔实验平台,对不同气相进料风速、不同喷淋密度下管式、槽式及管槽式分布器的液体分布情况和整塔压降,以及壁流效应进行了实验测定。实验结果表明:风速对分布器的液态分布性能没有太大的影响。随着喷淋密度的增大,新型管槽式液体分布器的不均匀系数逐渐下降,最大喷淋密度[L=6.99m3/(m2·h)]时其值接近0,相对于管式和槽式分布器分别下降6%和11%。不同风速下,管槽式分布器相对于管式、槽式分布器的整塔压降最高分别降低24%和16%;而且管槽式分布器壁流效应比管式与槽式的更不明显。最后,针对实验中管槽式分布器出现的问题,进行了分析并提出进一步优化的方案。对于在工业生产中喷淋密度大都大于实验时的喷淋密度,新型管槽式分布器将有更优异的表现,具有很好的规模化应用前景。

电站锅炉双可调煤粉分配器气固两相流动特性研究

针对制粉系统一次风粉的流动均匀性会直接影响锅炉的安全性与经济性,提出了一种双可调煤粉分配器。利用环形渐缩阀将风粉两相流分离为浓相流和稀相流,使用开度可调的扇形阀分别调整风粉流量,最后将浓、稀两股流体混合均匀,同时计算了内部结构对煤粉分配器进出口压降分配效果的影响。结果表明:渐缩角度范围取65°~75°较合适,高度占比不宜超过60%;风粉分离过程对粒径大于等于50μm的煤粉颗粒具有较好的分离效果;稀相扇形阀对单支管最大出口风速偏差为-28.63%,浓相扇形阀对单支管最大出口粉量偏差为-32.61%;该分配器对风粉调控具有较好的独立性,可以显著提高风粉系统流动的均匀性和调节灵活性。

气-液分流式分布器的实验研究

气-液分布器作为滴流床加氢反应器中的重要内构件,可有效抑制催化剂的结焦和失活,延长催化剂的使用寿命和反应器的运转周期。通过冷模实验研究了进气孔数量及气、液进孔中心间距(Δh)对一种气-液分流式分布器的抗塔板倾斜性能、液体分散性能以及阻力损失等流体力学性能的影响。实验结果表明,两气孔型气-液分流式分布器的抗塔板倾斜性能要优于四气孔型。两气孔型分布器的抗塔板倾斜性能和液体分散性能均随Δh的增加呈现先增强后减弱的趋势,且均在Δh=55 mm时达到最优。而在相同的气、液流量下,阻力损失则随Δh的增加呈现单调递减的变化趋势。

A Parametric Study for High-Efficiency Gas-Liquid Separator Design

A gas liquid centrifugal separator is widely used in industry on account of its simple geometry and little maintenance. These separators have considerable advantages over filters, scrubbers or precipitators in term of compact design, lower pressure drop and higher capacity. A gas liquid centrifugal separator is a device that utilizes centrifugal forces and low pressure caused by rotational motion to separate liquid from gas by density differences. Efficient and reliable separation is required for the optimum operation. These separators are often operated at less than peak efficiency due to the entrainment of separated liquid through an outlet pipe which is closely associated with the very complicated flow phenomena involved. Design parameters such as length of the separation space, vane exit angle, inlet to outlet diameter ratio, models for separation efficiency and pressure drop as a function of physical dimensions are not available in literature. This leaves the designer with very little to go on except known designs and experimentation. The aim of present study is to perform a parametric study to get higher efficiency for gas-liquid separator. A parametric study has been carded out with the help of CFD tools to analyze a separation performance of a centrifugal separator by varying the length of separator space. The best design parameters are analyzed based upon obtained results, tangential velocities, vortices, total pressure losses. From the present study several attempts are made to improve the performance of conventional centrifugal separators.

新技术在传统填料塔中的应用

根据填料塔内气液传质的特点,将填料由固定改为跳动形式,采用新型的气液分布器、雾沫分离器,增加防壁流环等,提高传质效率,降低阻力。

Two-phase flow distributors for fuel cell flow channels

All existing proton exchange membrane （PEM） fuel cell gas flow fields have been designed on the basis of single-phase gas flow distribution. The presence of liquid water in the flow causes non-uniform gas distribution, leading to poor cell performance. This paper demonstrates that a gas flow restrictor/distributor, as is commonly used in two-phase flow to stabilize multiphase transport lines and multiphase reactors, can improve the gas flow distribution by significantly reducing gas real-distribution caused by either non-uniform water formation in parallel flow channels or flow instability associated with negative-slope pressure drop characteristic of two-phase horizontal flow systems.

Experimental investigation on separation characteristics of axial cyclone separator

Axial cyclone separator has been widely applied in chemical production as an efficient gas-liquid separation device.In this study,a new axial cyclone separator with integrated swirler and exhaust pipe is designed to achieve the development goal of compact structure for advanced engine,and the distribution characteristics of swirling flow patterns as well as the variation in separation characteristics are investigated under slug flow pattern.Based on flow visualizations and fluctuation characteristics of pressure signals,three typical flow patterns,namely,slug flow,swirling intermittent flow,and swirling annular flow,in the horizontal swirling separation flow are characterized.It is investigated how the inlet conditions affect the separation characteristic parameters.The separation purity and extreme points of the air separation efficiency are independent of the inlet liquid flow rate.The separation pressure drop is quadratically related to the inlet air flow rate.Based on the drift-flux model and other methods,the prediction methods for the air separation efficiency and pressure drop are proposed,and the prediction accuracy is within±20%,which may provide instructions for the practical application of axial cyclone separator.

组合式旋流器处理污水的数值分析

利用RNG k-ε模型计算流量分配器,确定了组合式旋流分离器的结构形式,利用雷诺应力模型(RSM)对入口切向角度不同的旋流分离器内部流场进行了分析,利用离散相模型(DPM)计算了其分离效率,利用所设计的组合式旋流分离器进行污泥浓缩实验,确定了流量分配器的结构形式,得到斜切单入口式旋流分离器入口与分配器环形管外圆周面的最佳夹角为5°,该分离器可将污水的含固率从2.7%提升至7.1%.

Investigation of Self-Priming Process of a Centrifugal Pump with Double Blades

The gas-liquid two-phase flow patterns of a centrifugal pump during the self-priming process were investigated numerically and experimentally.The Euler-Euler multiphase model and SST k-ω turbulence model were applied for simulating the self-priming process.Meanwhile,the changes of motor speed and self-priming height were considered in the simulation.The overall transient two-phase flow features and water level distributions were mapped.Results showed that the self-priming process was divided into three stages.The liquid level in inlet-pipe rose in oscillation during self-priming process.The variations of water level during self-priming process of numerical simulation and test result agreed well.The inlet-pipe(Ver)was filled at 22 s and 24 s respectively numerically and experimentally.The bubble cloud circulated in the volute during middle stage of self-priming process,and breakup into smaller bubbles by shear force and tongue,and then discharged into chamber.The bubbles in the outlet-pipe mainly included bubbly flow and slug flow at the last stage of self-priming process,which is morphologically consistent with the test results.Also,during the self-priming process,the reflux liquid was pressed by blades and fully mixed with gas;that is the way to realizing the function of self-priming.