两相淋滤实验在深海铁锰结核研究中的应用

两相淋滤实验能够分离深海铁锰结核的水生矿物相和残留矿物相组分,为研究深海铁锰结核成矿作用以及古海洋环境提供直接信息。为了探讨两相淋滤实验在不同成因类型铁锰结核成矿作用研究中与全岩样品分析结果的差异,本文选取了西太平洋海山区和东太平洋CC区6个站位的铁锰结核样品进行了全岩样品矿物学和元素地球化学分析,利用两相淋滤实验分别提取了铁锰结核样品的水生矿物相和残留矿物相组分,并进行了元素地球化学分析。结果表明,不同类型铁锰结核的两相淋滤实验中残留相质量占比为14.0%~17.6%,变化较小,残留矿物相组分中Nb、Rb、Ta、Ti、Zr等元素含量较高。水生矿物相组分中的Co、Ni、Cu、Zn、Sr、REY元素含量及其比值变化与全岩样品基本一致。水生矿物相与残留矿物相中Ti、Nb、Sr含量的比值与全岩样品的Mn Fe值呈较好的负相关关系,可作为研究铁锰结核成矿环境的指标参数。

论“气液、气固两相流动及实验技术”研究生全英文课程建设

研究生全英文课程建设是我国高等教育国际化的必然选择。为使全英文课程适应于国际化人才培养和国家发展战略的需求,必须运用新的理念指导课程建设的各个环节。结合承担研究生“气液、气固两相流动及实验技术”全英文课程建设项目的实践经历,从课程网站建设、教学方法及教学问题的对策、考核方法革新、师资队伍建设四个方面,提供了建设高质量全英文课程的具体措施。课程建设取得良好成效,可为其他研究生全英文课程建设和教学改革提供参考和借鉴。

应用两相流动实验测定白垩岩心栓的含油／水饱和度函数

本文提出了一种测定低渗透性岩样的含油／水饱和度、也就是毛细压力和相对渗透率的新方法，该方法在注水实验中利用了显著的末端效应。在毛细压力高的岩样中，由于受这种末端效应的影响；测定了饱和度函数值出现较宽的间隔。根据复杂的岩心注水图表中列出的流体分布及生产数据，利用最小二乘法就可以计算出排泄和渗吸时的饱和度函数。应用化学漂移NMR技术测定流体分布，利用不同的数据组计算饱和度函数，这样就可以避免不符合要求的相互关联。当毛细压力和相对渗透率中存在滞后现象时，Killongh方法可以解释其扫描影响。该方法在北海白垩岩样实验中已经得到证实，其实验时间介于离心机法和多孔板法之间。

含碰撞式分离元件塔结构优化及水力性能研究

大通量塔可以有效降低塔体直径,节约塔器制造成本,是塔器重要的发展方向。由于塔操作点一般位于雾沫夹带线以上,故提出一种结合高效气液分离方法的塔结构。利用CFD数值模拟方法,分析了新型碰撞式气液分离结构的原理,计算了结构参数对分离效果的影响并对其结构进行优化。基于CFD分析结果,搭建实验平台,研究新型塔水力学性能,结果表明:1)分离元件层数越多、横向间距越小、纵向间距越小,此碰撞分离元件的分离效率越好,但阻力降也越大;2)综合效率和压降以及空间利用率可知,元件层数为2,且横向间距与宽度比值为1.0,纵向间距与宽度比值为0.5时,整个碰撞分离元件的效果最佳;3)当气相流量为定值时,表明改变液相流量对塔板压降无显著作用,当液相流量为定值时,塔板各层压降与气体流量正相关;4)改变液体流量对漏液线及雾沫夹带线无明显影响,且操作范围较广。因此,与传统旋流塔相比,新型含碰撞式分离元件高速塔具有塔径小、处理量大、气液分离效率高及操作范围广等优点,能够大幅降低成本,提升空间利用率,应用前景广泛。

Experimental detection of bubble-wall interactions in a vertical gas–liquid flow

Bubble motions and bubble-wall interactions in stagnant liquid were experimentally investigated by high-speed CCD and PIV technique with the main feature parameters such as E?tv?s numbers Eo = 0.98–1.10, Morton number Mo = 3.21 × 10^(-9)and Reynolds numbers Re = 180 ~ 190. The effect of bubble injecting frequency and the distance S between the gas injection nozzle and the wall on the statistical trajectory of bubbles, average velocity distribution of flow field and Reynolds shear stress were studied in detail. It was shown that the combination of bubble injecting frequency and the distance S caused different bubble motion forms and hydrodynamic characteristics.When the normalized initial distance was very little, like S*≈ 1.2(here S*= 2S/d_e, and deis the bubble equivalent diameter), bubbles ascended in a zigzag trajectory with alternant structure of high and low speed flow field around the bubbles, and the distribution of positive and negative Reynolds shear stress looked like a blob. With the increase of distance S*, bubbles' trajectory would tend to be smooth and straight from the zigzag curve. Meanwhile, with the increase of bubble injecting frequency, the camber of bubble trajectory at 20<y<60 mm had a slight increase due to the inhibitory effect from the vertical wall. Under larger spacing, such as S*≈ 3.6, the low-frequency bubbles gradually moved away from the vertical plane wall in a straight trajectory and the high-frequency bubbles gradually moved close to the vertical wall in a similar straight trajectory after an unstable camber motion. Under the circumstances, high-speed fluid was mainly distributed in the region between the wall and the bubbles, while the relative large Reynolds shear stress mainly existed in the region far away from the wall.

An Experimental Study on the Flow Characteristics of OilWater Two-Phase Flow in Horizontal Straight Pipes

The flow patterns and their transitions of oil-water two-phase flow in horizontal pipes were studied. The experiments were conducted in two kinds of horizontal tubes, made of plexiglas pipe and stainless steel pipe with 40 mm ID respectively. No. 46 mechanical oil and tap water were used as working fluids. The superflcial velocity ranges of oil and water were: 0.04-1.2m·s-1 and 0.04-2.2m·s-1, respectively. The flow patterns were identified by visualization and by transient fluctuation signals of differential pressure drop. The flow patterns were defined according to the relative distribution of oil and water phases in the pipes. Flow pattern maps were obtained for both pipelines. In addition, semi-theoretical transition criteria for the flow patterns were proposed, and the proposed transitional criteria are in reasonable agreement with available data in liquid-liquid systems.

Water invasion and remaining gas distribution in carbonate gas reservoirs using core displacement and NMR

Water invasion is a common phenomenon in gas reservoirs with active edge-and-bottom aquifers.Due to high reservoir heterogeneity and production parameters,carbonate gas reservoirs feature exploitation obstacles and low recovery factors.In this study,combined core displacement and nuclear magnetic resonance(NMR)experiments explored the reservoir gas−water two-phase flow and remaining microscopic gas distribution during water invasion and gas injection.Consequently,for fracture core,the water-phase relative permeability is higher and the co-seepage interval is narrower than that of three pore cores during water invasion,whereas the water-drive recovery efficiency at different invasion rates is the lowest among all cores.Gas injection is beneficial for reducing water saturation and partially restoring the gas-phase relative permeability,especially for fracture core.The remaining gas distribution and the content are related to the core properties.Compared with pore cores,the water invasion rate strongly influences the residual gas distribution in fracture core.The results enhance the understanding of the water invasion mechanism,gas injection to resume production and the remaining gas distribution,so as to improve the recovery factors of carbonate gas reservoirs.

Recent Progress in JAXA Project of Boiling Two-Phase Flow Experiment onboard ISS

The amount of waste heat in a space facility became larger, because of increase in the space platform size and its power consumption. It requires development of high-performance space thermal management systems handling a large amount of waste. Boiling two-phase flow could become powerful means for this system because a boiling and condensation system is one of the most efficient modes of heat transfer due to phase change （liquid-vapor）. However, gravity effects on boiling two-phase flow phenomena and the corresponding heat transfer characteristics are not clear. Therefore, we prepare the experiments of boiling two-phase flow utilizing a long-term microgravity environment onboard a Japanese Experimental Module ＂KIBO＂ in the International Space Station （ISS） as one of the JAXA official projects. In this paper, recent progress of the preparation for the project is reported.

Gas-Liquid Two-Phase Axial Backmixing Through Structured Packing at Elevated Pressure

An experimental study of the extent of axial backmixing in both gas and liquid phases was conducted in a 150 mm ID column packed with Mellapak 250Y corrugated structured packing. The column was operated at pressures ranging from 0.3 MPa to 2.0MPa with nitrogen and water flowing countercurrently through the packing. The amount of axial backmixing was experimentally evaluated by the pulse response techniques using hydrogen in gas phase and an aqueous solution of NaCl in liquid phase as inert tracers. The response of the tracer was monitored by means of thermal conductivity in the gas phase and electrical conductance in the liquid phase. The experimentally determined residence time distribution (RTD) curves were interpreted in terms of the diffusion-type modei. The results indicated that the axial backmixing in the gas increased notably with gas flowrate and slightly with operating pressure and liquid flowrate. The liquid-phase axial backmixing was an increasing function of both gas and liquid flowrates and insensitive to pressure. Various correlations were developed for reproducing the experimental mixing data. The agreement between experimental and correlated data appeared to be acceptable and within ±20% of difference.

Numerical Investigation of a New Method for Reducing Bends Erosion from Particles Impacts

The present paper intends to introduce a new method for reducingbends erosion from particles impacts: the ribbed bend erosionprotection method. Ribs are evenly fixed in the range of 20 deg-80deg on the inner-wall of inside 90 deg bend and the bend (includingribs) is made of medium carbon steel. Three-dimensional numericalworks is performed and the result shows satisfactory agreement withthe experimental measurement. Numerical simulation studies thecharacteristics of axial gas flow along the bend and secondary flowat cross section.

Developments in the understanding of gas–solid contact efficiency in the circulating fluidized bed riser reactor:A review

In the last several decades, circulating fluidized bed reactors have been studied in many aspects including hydrodynamics, heat and mass transfer and gas–solid two phase contacting. However, despite the abundance of review papers on hydrodynamics, there is no summary paper on gas–solid contact efficiency to date, especially on high density circulating fluidized beds(CFBs). This paper gives an introduction to, and a review of the measurement of contact efficiency in circulating fluidized bed riser. Firstly, the popular testing method of contact efficiency including the method of heating transfer experiment and hot model reaction are discussed, then previous published papers are reviewed based on the discussed methods. Some key results of the experimental work are described and discussed. Gas–solid contact efficiency is affected by the operating conditions as well as the particle size distribution. The result of the contact efficiency shows that the CFB riser is far away from an ideal plug flow reactor due to the characteristics of hydrodynamics in the riser. Lacunae in the available literature have been delineated and recommendations have been made for further work.

Experimental analysis on adjusting performance of vapor-liquid two-phase flow controller

The vapor-liquid self-adjusting controller is an innovative automatic regulating valve.In order to ensure adjusted objects run safely and economically,the controller automatically adjusts the liquid flux to keep liquid level at a required level according to physical properties of vapor-liquid two-phase fluid.The adjusting mechanics,the controller’s performance and influencing factors of its stability have been analyzed in this paper.The theoretical analysis and successful applications have demonstrated this controller can keep the liquid level steady with good performance.The actual application in industry has shown that the controller can satisfactorily meet the requirement of industrial production and has wide application areas.

Experimental Acoustic Determination of the Void Fraction in Two-Phase Flow in Horizontal Pipelines

In multi-phase flows, the phases can flow and arranged in different spatial configurations in the pipe, which called flow patterns. This type of flow is found in the oil, chemical and nuclear industries. For example, in the production and transport of oil and gas, the identification of the flow patterns are essential for answering those questions which are related to the economic return of the field, such as, measuring the volumetric flow, determining the pressure drop along the flow lines, production management and supervision. In offshore production, these factors are very important. This paper presents a new method for measuring the void fraction in horizontal pipelines, taking the air as gas in water-air two-phase flow. Through acoustic analysis of the frequency response of the pipe, the method gets the parameters to changes in runoff regime, in an experimental arrangement constructed on a small scale. The main advantages are the non-intrusive characteristic and easy to implement. The paper is composed of a qualitative experimental evaluation and transducers （microphone） which are used to analyze variations in the response accompanying variations in void and flow pattern changes. Changes are imposed and controlled by a two-phase flow experimental simulation rig, including a measurement cell constituted of an external casing that can isolate the measurement from the environmental background noise fitted with acoustic pressure transducers radially arranged, and the impact of a monitored excitation mechanism. The signals which captured by the microphones are processed and analyzed by checking their frequency contents changes according to the amount of air in the mixture.

Experimental Investigation of Boiling Two-phase Flow Instability of Nitrogen in a Vertical Tube

Boiling flow instability of nitrogen in a vertical tube is experimentally investigated in the present study. The experiments reveal that pressure has a significant effect on the characteristics of the heat flux-mass flux type boiling flow instability.First.the pressure has strong effects on both the developing time and the fluctuation amplitude.Especially increasing pressure leads to decrease the fluctuating amplitude of mass flux.Then,the mass flux evolving curves under different pressures feature out a shape like a leaf.The characteristics of the heat flux-mass flux type boiling flow instability under lower pressure are very complicated,however,with increasing pressure,this type of instability is gradually suppressed.

Numerical Simulation and Experiment Analyses for the Gas-liquid Two-phase Vortex Pump

Based on the gas-liquid two-phase mixture transportation test, the k-c-A; turbulence model was applied to simulate the two-phase turbulent flow in a vortex pump. By comparing the simulation and experiment results, inner flow features were revealed. The bubbles in the channel distribute mainly at the pressure side of the blades, and the aggregation degree of the bubbles is enhanced with an increase in inlet gas volume fraction. Experimental results indicate that the influence of the gas phase on vortex pump performance is small when the gas volume fraction is less than 10%. When the gas volume fraction contiuuously increases to 15%, the characteristic curves abruptly drop due to the gas blocking phenomenon.

Experimental Observation of Two Phase Flow of R123 Inside a Herringbone Microfin Tube

Vapor-liquid two phase flow behavior of R123 inside herringbone microfin tubes has been studied. Herringbone microfin tube is a kind of internally finned tube in which microfins are installed inside the tube where the microfins form multi-V-shape in flow direction. For the present experiment three different types of herringbone microfin tubes with helix angle B = 8, 14 and 28 are used. Experimental observations showed how flow diverges and converges inside herringbone microfin tube due to fin arrangement. The effect is more remarkable for larger helix angle. From the measurements of the cross-sectional liquid flow rate distribution, the liquid removal and collection and the entrained droplet are discussed. Quantity of liquid droplets is increased with increase of helix angle. The tube with helix angle B = 28 shows higher quantity of liquid droplets than others.

Experimental Study on the Condensation of a Thermosyphon by Electrical Capacitance Tomography

The study on the condensation and the two-phase flow pattern in the condensation section is important to understand the operating mechanisms in a thermosyphon. In this paper, a new electric capacitance tomography(ECT) sensor was designed for the visualization measurement in a liquid by removing the shielding case and sealing with insulating hydrophobic material. It was successfully used to measure the condensation process in a thermosyphon under different operating temperatures. The thermosyphon was made of silica glass, and alcohol was used as a working fluid. The alcohol vapor was cooled to condense through the heat convection with the cooling water. The operating temperature was controlled by a heater with different power outputs. The experimental results show that the alcohol vapor condensed in stripes and unevenly on the wall surface at a low operating temperature. The liquid bridge will be formed periodically at the operating temperature of 90?C, and the time interval between two liquid bridges will be shorter with the increase of the operating temperature. At 117?C or even higher operating temperatures, the complete liquid bridge cannot be formed sometimes due to the difference of the growth rate of the surface wave around the circumference.