WorldWideScience

Sample records for gas liquid flows

  1. Advances in gas-liquid flows 1990

    International Nuclear Information System (INIS)

    Kim, J.M.; Hashemi, A.

    1990-01-01

    Gas-liquid two-phase flows commonly occur in nature and industrial applications. Rain, clouds, geysers, and waterfalls are examples of natural gas-liquid flow phenomena, whereas industrial applications can be found in nuclear reactors, steam generators, boilers, condensers, evaporators, fuel atomization, heat pipes, electronic equipment cooling, petroleum engineering, chemical process engineering, and many others. The household-variety phenomena such as garden sprinklers, shower, whirlpool bath, dripping faucet, boiling tea pot, and bubbling beer provide daily experience of gas-liquid flows. The papers presented in this volume reflect the variety and richness of gas-liquid two-phase flow and the increasing role it plays in modern technology. This volume contains papers dealing with some recent development in gas-liquid flow science and technology, covering basic gas-liquid flows, measurements and instrumentation, cavitation and flashing flows, countercurrent flow and flooding, flow in various components and geometries liquid metals and thermocapillary effects, heat transfer, nonlinear phenomena, instability, and other special and general topics related to gas-liquid flows

  2. Gas/liquid flow configurations

    International Nuclear Information System (INIS)

    Bonin, Jacques; Fitremann, J.-M.

    1978-01-01

    Prediction of flow configurations (morphology) for gas/liquid or liquid/vapour mixtures is an important industrial problem which is not yet fully understood. The ''Flow Configurations'' Seminar of Societe Hydrotechnique de France has framed recommendations for investigation of potential industrial applications for flow configurations [fr

  3. Gas-liquid flow filed in agitated vessels

    International Nuclear Information System (INIS)

    Hormazi, F.; Alaie, M.; Dabir, B.; Ashjaie, M.

    2001-01-01

    Agitated vessels in form of sti reed tank reactors and mixed ferment ors are being used in large numbers of industry. It is more important to develop good, and theoretically sound models for scaling up and design of agitated vessels. In this article, two phase flow (gas-liquid) in a agitated vessel has been investigated numerically. A two-dimensional computational fluid dynamics model, is used to predict the gas-liquid flow. The effects of gas phase, varying gas flow rates and variation of bubbles shape on flow filed of liquid phase are investigated. The numerical results are verified against the experimental data

  4. Void fraction fluctuations in two-phase gas-liquid flow

    International Nuclear Information System (INIS)

    Ulbrich, R.

    1987-01-01

    Designs of the apparatus in which two-phase gas-liquid flow occurs are usually based on the mean value of parameters such as pressure drop and void fraction. The flow of two-phase mixtures generally presents a very complicated flow structure, both in terms of the unsteady formation on the interfacial area and in terms of the fluctuations of the velocity, pressure and other variables within the flow. When the gas void fraction is near 0 or 1 / bubble or dispersed flow regimes / then oscillations of void fraction are very small. The intermittent flow such as plug and slug/ froth is characterized by alternately flow portions of liquid and gas. It influences the change of void fractions in time. The results of experimental research of gas void fraction fluctuations in two-phase adiabatic gas-liquid flow in a vertical pipe are presented

  5. A study of stratified gas-liquid pipe flow

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, George W.

    2005-07-01

    This work includes both theoretical modelling and experimental observations which are relevant to the design of gas condensate transport lines. Multicomponent hydrocarbon gas mixtures are transported in pipes over long distances and at various inclinations. Under certain circumstances, the heavier hydrocarbon components and/or water vapour condense to form one or more liquid phases. Near the desired capacity, the liquid condensate and water is efficiently transported in the form of a stratified flow with a droplet field. During operating conditions however, the flow rate may be reduced allowing liquid accumulation which can create serious operational problems due to large amounts of excess liquid being expelled into the receiving facilities during production ramp-up or even in steady production in severe cases. In particular, liquid tends to accumulate in upward inclined sections due to insufficient drag on the liquid from the gas. To optimize the transport of gas condensates, a pipe diameters should be carefully chosen to account for varying flow rates and pressure levels which are determined through the knowledge of the multiphase flow present. It is desirable to have a reliable numerical simulation tool to predict liquid accumulation for various flow rates, pipe diameters and pressure levels which is not presently accounted for by industrial flow codes. A critical feature of the simulation code would include the ability to predict the transition from small liquid accumulation at high flow rates to large liquid accumulation at low flow rates. A semi-intermittent flow regime of roll waves alternating with a partly backward flowing liquid film has been observed experimentally to occur for a range of gas flow rates. Most of the liquid is transported in the roll waves. The roll wave regime is not well understood and requires fundamental modelling and experimental research. The lack of reliable models for this regime leads to inaccurate prediction of the onset of

  6. Flow-pattern identification and nonlinear dynamics of gas-liquid two-phase flow in complex networks.

    Science.gov (United States)

    Gao, Zhongke; Jin, Ningde

    2009-06-01

    The identification of flow pattern is a basic and important issue in multiphase systems. Because of the complexity of phase interaction in gas-liquid two-phase flow, it is difficult to discern its flow pattern objectively. In this paper, we make a systematic study on the vertical upward gas-liquid two-phase flow using complex network. Three unique network construction methods are proposed to build three types of networks, i.e., flow pattern complex network (FPCN), fluid dynamic complex network (FDCN), and fluid structure complex network (FSCN). Through detecting the community structure of FPCN by the community-detection algorithm based on K -mean clustering, useful and interesting results are found which can be used for identifying five vertical upward gas-liquid two-phase flow patterns. To investigate the dynamic characteristics of gas-liquid two-phase flow, we construct 50 FDCNs under different flow conditions, and find that the power-law exponent and the network information entropy, which are sensitive to the flow pattern transition, can both characterize the nonlinear dynamics of gas-liquid two-phase flow. Furthermore, we construct FSCN and demonstrate how network statistic can be used to reveal the fluid structure of gas-liquid two-phase flow. In this paper, from a different perspective, we not only introduce complex network theory to the study of gas-liquid two-phase flow but also indicate that complex network may be a powerful tool for exploring nonlinear time series in practice.

  7. Effect of wall wettability on flow characteristics of gas-liquid two-phase flow

    International Nuclear Information System (INIS)

    Uematsu, Junichi; Abe, Kazuya; Hazuku, Tatsuya; Takamasa, Tomoji; Hibiki, Takashi

    2007-01-01

    To evaluate the effect of surface wettability in pipe wall on flow characteristics in a vertical upward gas-liquid to-phase flow, visualization study was performed using three test pipes, namely an acrylic pipe, a hydrophilic pipe, a hydrophobic pipe. Such basic flow characteristics as flow patterns and void fraction were investigated in these three pipes. In the hydrophilic pipe, the slug flow-to-churn flow transition boundary was shifted to higher gas velocity condition at a given liquid velocity, whereas the churn flow-to-annular flow transition boundary was shifted to lower gas velocity condition at a given liquid velocity. In the hydrophobic pipe, the inverted-churn flow regime was observed in the region where the churn flow regime was observed in the acrylic pipe, whereas the droplet flow regime was observed in the region where the annular flow regime was observed in the acrylic pipe. At high-gas flow rate condition, the mean void fraction in the hydrophobic pipe took relatively higher value to that in the acrylic pipe. (author)

  8. Gas flow headspace liquid phase microextraction.

    Science.gov (United States)

    Yang, Cui; Qiu, Jinxue; Ren, Chunyan; Piao, Xiangfan; Li, Xifeng; Wu, Xue; Li, Donghao

    2009-11-06

    There is a trend towards the use of enrichment techniques such as microextraction in the analysis of trace chemicals. Based on the theory of ideal gases, theory of gas chromatography and the original headspace liquid phase microextraction (HS-LPME) technique, a simple gas flow headspace liquid phase microextraction (GF-HS-LPME) technique has been developed, where the extracting gas phase volume is increased using a gas flow. The system is an open system, where an inert gas containing the target compounds flows continuously through a special gas outlet channel (D=1.8mm), and the target compounds are trapped on a solvent microdrop (2.4 microL) hanging on the microsyringe tip, as a result, a high enrichment factor is obtained. The parameters affecting the enrichment factor, such as the gas flow rate, the position of the microdrop, the diameter of the gas outlet channel, the temperatures of the extracting solvent and of the sample, and the extraction time, were systematically optimized for four types of polycyclic aromatic hydrocarbons. The results were compared with results obtained from HS-LPME. Under the optimized conditions (where the extraction time and the volume of the extracting sample vial were fixed at 20min and 10mL, respectively), detection limits (S/N=3) were approximately a factor of 4 lower than those for the original HS-LPME technique. The method was validated by comparison of the GF-HS-LPME and HS-LPME techniques using data for PAHs from environmental sediment samples.

  9. Drift-flux parameters for upward gas flow in stagnant liquid

    International Nuclear Information System (INIS)

    Kataoka, Yoshiyuki; Suzuki, Hiroaki; Murase, Michio

    1987-01-01

    The drift-flux model is widely used for gas-liquid two phase flow analysis, because it is applicable to various flow patterns and a wide range of void fractions. The drift-flux parameters for upward gas flow in stagnant liquid, however, have not been well examined. In this study, the distribution parameter C o and the drift velocity V gj for stagnant liquid were derived from the void fraction correlation and boundary conditions of drift-flux parameters, and then compared with C o and V gj for high liquid velocities. Also using the two region model where a circular flow area was divided into an inner region of cocurrent up-flow and an outer annulus region of liquid down flow, C o and V gj for stagnant liquid and for high liquid velocity were compared. The results showed that C o values for stagnant liquid were larger than values for high liquid velocity, while V gj values were almost the same for both cases. (author)

  10. Entropy feature extraction on flow pattern of gas/liquid two-phase flow based on cross-section measurement

    International Nuclear Information System (INIS)

    Han, J; Dong, F; Xu, Y Y

    2009-01-01

    This paper introduces the fundamental of cross-section measurement system based on Electrical Resistance Tomography (ERT). The measured data of four flow regimes of the gas/liquid two-phase flow in horizontal pipe flow are obtained by an ERT system. For the measured data, five entropies are extracted to analyze the experimental data according to the different flow regimes, and the analysis method is examined and compared in three different perspectives. The results indicate that three different perspectives of entropy-based feature extraction are sensitive to the flow pattern transition in gas/liquid two-phase flow. By analyzing the results of three different perspectives with the changes of gas/liquid two-phase flow parameters, the dynamic structures of gas/liquid two-phase flow is obtained, and they also provide an efficient supplementary to reveal the flow pattern transition mechanism of gas/liquid two-phase flow. Comparison of the three different methods of feature extraction shows that the appropriate entropy should be used for the identification and prediction of flow regimes.

  11. Study of gas-liquid flow in model porous media for heterogeneous catalysis

    Science.gov (United States)

    Francois, Marie; Bodiguel, Hugues; Guillot, Pierre; Laboratory of the Future Team

    2015-11-01

    Heterogeneous catalysis of chemical reactions involving a gas and a liquid phase is usually achieved in fixed bed reactors. Four hydrodynamic regimes have been observed. They depend on the total flow rate and the ratio between liquid and gas flow rate. Flow properties in these regimes influence transfer rates. Rather few attempts to access local characterization have been proposed yet, though these seem to be necessary to better describe the physical mechanisms involved. In this work, we propose to mimic slices of reactor by using two-dimensional porous media. We have developed a two-dimensional system that is transparent to allow the direct observation of the flow and the phase distribution. While varying the total flow rate and the gas/liquid flow rate ratio, we observe two hydrodynamic regimes: at low flow rate, the gaseous phase is continuous (trickle flow), while it is discontinuous at higher flow rate (pulsed flow). Thanks to some image analysis techniques, we are able to quantify the local apparent liquid saturation in the system. Its fluctuations in time are characteristic of the transition between the two regimes: at low liquid flow rates, they are negligible since the liquid/gas interface is fixed, whereas at higher flow rates we observe an alternation between liquid and gas. This transition between trickle to pulsed flow is in relative good agreement with the existing state of art. However, we report in the pulsed regime important flow heterogeneities at the scale of a few pores. These heterogeneities are likely to have a strong influence on mass transfers. We acknowledge the support of Solvay.

  12. Study on Gas-liquid Falling Film Flow in Internal Heat Integrated Distillation Column

    Science.gov (United States)

    Liu, Chong

    2017-10-01

    Gas-liquid internally heat integrated distillation column falling film flow with nonlinear characteristics, study on gas liquid falling film flow regulation control law, can reduce emissions of the distillation column, and it can improve the quality of products. According to the distribution of gas-liquid mass balance internally heat integrated distillation column independent region, distribution model of heat transfer coefficient of building internal heat integrated distillation tower is obtained liquid distillation falling film flow in the saturated vapour pressure of liquid water balance, using heat transfer equation and energy equation to balance the relationship between the circulating iterative gas-liquid falling film flow area, flow parameter information, at a given temperature, pressure conditions, gas-liquid flow falling film theory makes the optimal parameters to achieve the best fitting value with the measured values. The results show that the geometric gas-liquid internally heat integrated distillation column falling film flow heat exchange area and import column thermostat, the average temperature has significant. The positive correlation between the heat exchanger tube entrance due to temperature difference between inside and outside, the heat flux is larger, with the increase of internal heat integrated distillation column temperature, the slope decreases its temperature rise, which accurately describes the internal gas-liquid heat integrated distillation tower falling film flow regularity, take appropriate measures to promote the enhancement of heat transfer. It can enhance the overall efficiency of the heat exchanger.

  13. Analysing Gas-Liquid Flow in PEM Electrolyser Micro-Channels

    DEFF Research Database (Denmark)

    Lafmejani, Saeed Sadeghi; Olesen, Anders Christian; Kær, Søren Knudsen

    2016-01-01

    and are fairly expensive. One means of increasing the hydrogen yield to cost ratio of such systems, is to increase the operating current density. However, at high current densities, management of heat and mass transfer in the anode current collector and channel becomes crucial. This entails that further...... understanding of the gas-liquid flow in both the porous media and the channel is necessary for insuring proper oxygen, water and heat management of the electrolysis cell. In this work, the patterns of vertical upward gas-liquid flow in a 5×1×94 mm micro-channel are experimentally analysed. A sheet of titanium...... felt is used as a permeable wall for permeation of air through a column of water similar to the phenomenon encountered at the anode. The transparent setup is operated ex-situ and the gas-liquid flow regimes are identified using a camera....

  14. Coupling of a two phase gas liquid 3D Darcy flow in fractured porous media with a 1D free gas flow

    OpenAIRE

    Brenner , Konstantin; Masson , Roland; Trenty , Laurent; Zhang , Yumeng

    2015-01-01

    A model coupling a three dimensional gas liquid compositional Darcy flow in a frac-tured porous medium, and a one dimensional compositional free gas flow is presented. The coupling conditions at the interface between the gallery and the porous medium account for the molar normal fluxes continuity for each component, the gas liquid thermody-namical equilibrium, the gas pressure continuity and the gas and liquid molar fractions continuity. The fractures are represented as interfaces of codimens...

  15. Study on cocurrent downtake gas-liquid flow in a vertical channel

    International Nuclear Information System (INIS)

    Lozovetskij, V.V.

    1978-01-01

    Hydraulic resistance and liquid stall from the film surface at cocurrent film and gas downflow in vertical channel in measurement range of reynolds number from 100 to 1260 for the film and from 1.2x10 4 to 10 5 for gas are studied. For downflow two regimes are characteristic: purely annular, that is separate phase flow regime, and the regime of stall and carrying liquid droplets from the film surface, that is annular dispersed flow regime. The existence boundaries of both regimes are determined and criterial equations for pressure drop calculation are obtained. It is established experimentally that at sufficient range from the liquid input place on the working zone the established two-phase flow takes place. In their nucleus two areas can be singled out, which differ by the flow density values of stalled liquid: central, having the permanent flow density value and area adjacent to the film surface, the liquid in the combs of waves making a significant contribution to the flow density value. At equal flooding density with the relative gas speed increase, the flow density value of stalled liquid in the channel central part increase. A similar result also takes place at flooding density increase at permanent relative speed. Flooding density and relative speed increase leads to levelling stalled liquid distribution about the channel cross section

  16. Continuous gas/liquid–liquid/liquid flow synthesis of 4-fluoropyrazole derivatives by selective direct fluorination

    Directory of Open Access Journals (Sweden)

    Jessica R. Breen

    2011-08-01

    Full Text Available 4-Fluoropyrazole systems may be prepared by a single, sequential telescoped two-step continuous gas/liquid–liquid/liquid flow process from diketone, fluorine gas and hydrazine starting materials.

  17. Analysing Gas-Liquid Flow in PEM Electrolyser Micro-Channels (Poster)

    DEFF Research Database (Denmark)

    Lafmejani, Saeed Sadeghi; Olesen, Anders Christian; Kær, Søren Knudsen

    One means of increasing the hydrogen yield to cost ratio of a PEM water electrolyser, is to increase the operating current density. However, at high current densities (higher than 1 A/cm2), management of heat and mass transfer in the anode current collector and channel becomes crucial and can lead...... to hot spots. Management of heat and fluid flow through the micro-channels play a great role in the capability of PEM water electrolysis when working at high current densities. Despite, many studies have been done on gas-liquid flows; still there is a lack of research on gas-liquid flows in micro......-sized channels (hydraulic diameter of 1 mm) of PEM water electrolysis. Precisely controlling all the parameters that affect the gas-liquid flow in a PEM water electrolysis cell is quite challenging, hence a simplified setup is constructed consisting of only a transparent channel with a sheet of titanium felt...

  18. Magnetic resonance velocity imaging of liquid and gas two-phase flow in packed beds.

    Science.gov (United States)

    Sankey, M H; Holland, D J; Sederman, A J; Gladden, L F

    2009-02-01

    Single-phase liquid flow in porous media such as bead packs and model fixed bed reactors has been well studied by MRI. To some extent this early work represents the necessary preliminary research to address the more challenging problem of two-phase flow of gas and liquid within these systems. In this paper, we present images of both the gas and liquid velocities during stable liquid-gas flow of water and SF(6) within a packing of 5mm spheres contained within columns of diameter 40 and 27 mm; images being acquired using (1)H and (19)F observation for the water and SF(6), respectively. Liquid and gas flow rates calculated from the velocity images are in agreement with macroscopic flow rate measurements to within 7% and 5%, respectively. In addition to the information obtained directly from these images, the ability to measure liquid and gas flow fields within the same sample environment will enable us to explore the validity of assumptions used in numerical modelling of two-phase flows.

  19. Statistic characteristics of the gas-liquid flow in a vertical minichannel

    Science.gov (United States)

    Kozulin, I. A.; Kuznetsov, V. V.

    2010-03-01

    The gas-liquid upward flow was studied in a rectangular minichannel of 1.75×3.8 mm and length of 0.7 m. The experiments were carried out within the range of the gas superficial velocity from 0.1 to 10 m/s and the liquid superficial velocity from 0.07 to 0.7 m/s for the co-current H2O/CO2 flow under the conditions of saturation. The method for the two-beam laser scanning of structure and determination of statistic characteristics of the two-phase flow was worked through. The slug-bubble, slug, transitional, churn, and annular flows were distinguished. The statistics characteristics of liquid and gas phases motion in a minichannel were obtained for the first time including the velocities of phase motion.

  20. Fundamental research of two-phase flows with high liquid/gas density ratios

    International Nuclear Information System (INIS)

    Mishima, Kaichiro; Hibiki, Takashi; Saito, Yasushi; Tobita, Yoshiharu; Konishi, Kensuke; Suzuki, Tohru

    2000-07-01

    In order to analyze the boiling of a fuel-steel mixture pool formed during the core disruptive accident in a fast breeder reactor, it is important to understand the flow characteristics of gas-liquid two-phase pools containing molten reactor materials. Since the liquid/gas density ratio is high, the characteristics of such two-phase flows may differ from those of ordinary flows such as water/air flow. In this study, as a fundamental research of two-phase flows with a high liquid/gas density ratio, the experiments were performed to visualize and measure molten metal (lead-bismuth)/nitrogen gas two-phase flows using a neutron radiography technique. From these experiments, fundamental data such as bubble shapes, void fractions and liquid velocity fields were obtained. In addition, the momentum exchange model of SIMMER-III, which has been developed by JNC, was assessed and improved using the experimental data. In the visualization by neutron radiography, it was found that deformed ellipsoidal bubbles could be seen with smaller gas flux or lower void fractions, and spherical cap bubbles could be seen with larger gas flux or higher void fractions. In addition, a correlation applicable to SIMMER-III was proposed through a comparison between the experimental data and traditional empirical correlations. Furthermore, a visualization experiment using gold-cadmium tracer particles showed that the image processing technique used in the quantification of void fractions is applicable to the measurement of the liquid velocity fields. On the other hand, in the analysis by SIMMER-III, it was confirmed that the original momentum exchange model was appropriate for ellipsoidal bobby flows and that the accuracy of SIMMER-III for cap bubbly flows was much improved with the proposed correlation. Moreover, a new procedure, in which the appropriate drag coefficient could be automatically selected according to bubble shape, was developed. The SIMMER-III code improved through this study can

  1. Ultrasonic Tomography Imaging for Liquid-Gas Flow Measurement

    Directory of Open Access Journals (Sweden)

    Muhammad Jaysuman PUSPPANATHAN

    2013-01-01

    Full Text Available This research was carried out to measure two-phase liquidgas flow regime by using a dual functionality ultrasonic transducer. Comparing to the common separated transmitter–receiver ultrasonic pairs transducer, the dual functionality ultrasonic transceiver is capable to produce the same measurable results hence further improvises and contributes to the hardware design improvement and system accuracy. Due to the disadvantages and the limitations of the separated ultrasonic transmitter–receiver pair, this paper presents a non-invasive ultrasonic tomography system using ultrasonic transceivers as an alternative approach. Implementation of ultrasonic transceivers, electronic measurement circuits, data acquisition system and suitable image reconstruction algorithms, the measurement of a liquid/gas flow was realized.

  2. A New Approach for Accurate Prediction of Liquid Loading of Directional Gas Wells in Transition Flow or Turbulent Flow

    Directory of Open Access Journals (Sweden)

    Ruiqing Ming

    2017-01-01

    Full Text Available Current common models for calculating continuous liquid-carrying critical gas velocity are established based on vertical wells and laminar flow without considering the influence of deviation angle and Reynolds number on liquid-carrying. With the increase of the directional well in transition flow or turbulent flow, the current common models cannot accurately predict the critical gas velocity of these wells. So we built a new model to predict continuous liquid-carrying critical gas velocity for directional well in transition flow or turbulent flow. It is shown from sensitivity analysis that the correction coefficient is mainly influenced by Reynolds number and deviation angle. With the increase of Reynolds number, the critical liquid-carrying gas velocity increases first and then decreases. And with the increase of deviation angle, the critical liquid-carrying gas velocity gradually decreases. It is indicated from the case calculation analysis that the calculation error of this new model is less than 10%, where accuracy is much higher than those of current common models. It is demonstrated that the continuous liquid-carrying critical gas velocity of directional well in transition flow or turbulent flow can be predicted accurately by using this new model.

  3. Coupling compositional liquid gas Darcy and free gas flows at porous and free-flow domains interface

    Energy Technology Data Exchange (ETDEWEB)

    Masson, R., E-mail: roland.masson@unice.fr [LJAD, University Nice Sophia Antipolis, CNRS UMR 7351 (France); Team COFFEE INRIA Sophia Antipolis Méditerranée (France); Trenty, L., E-mail: laurent.trenty@andra.fr [Andra, Chatenay Malabry (France); Zhang, Y., E-mail: yumeng.zhang@unice.fr [LJAD, University Nice Sophia Antipolis, CNRS UMR 7351 (France); Team COFFEE INRIA Sophia Antipolis Méditerranée (France)

    2016-09-15

    This paper proposes an efficient splitting algorithm to solve coupled liquid gas Darcy and free gas flows at the interface between a porous medium and a free-flow domain. This model is compared to the reduced model introduced in [6] using a 1D approximation of the gas free flow. For that purpose, the gas molar fraction diffusive flux at the interface in the free-flow domain is approximated by a two point flux approximation based on a low-frequency diagonal approximation of a Steklov–Poincaré type operator. The splitting algorithm and the reduced model are applied in particular to the modelling of the mass exchanges at the interface between the storage and the ventilation galleries in radioactive waste deposits.

  4. Droplets in annular-dispersed gas-liquid pipe-flows

    NARCIS (Netherlands)

    Van 't Westende, J.M.C.

    2008-01-01

    Annular-dispersed gas-liquid pipe-flows are commonly encountered in many industrial applications, and have already been studied for many decades. However, due to the great complexity of this type of flow, there are still many phenomena that are poorly understood. The aim of this thesis is to shed

  5. The effect of surfactant on stratified and stratifying gas-liquid flows

    Science.gov (United States)

    Heiles, Baptiste; Zadrazil, Ivan; Matar, Omar

    2013-11-01

    We consider the dynamics of a stratified/stratifying gas-liquid flow in horizontal tubes. This flow regime is characterised by the thin liquid films that drain under gravity along the pipe interior, forming a pool at the bottom of the tube, and the formation of large-amplitude waves at the gas-liquid interface. This regime is also accompanied by the detachment of droplets from the interface and their entrainment into the gas phase. We carry out an experimental study involving axial- and radial-view photography of the flow, in the presence and absence of surfactant. We show that the effect of surfactant is to reduce significantly the average diameter of the entrained droplets, through a tip-streaming mechanism. We also highlight the influence of surfactant on the characteristics of the interfacial waves, and the pressure gradient that drives the flow. EPSRC Programme Grant EP/K003976/1.

  6. Industrial aspects of gas-liquid two-phase flow

    International Nuclear Information System (INIS)

    Hewitt, G.F.

    1977-01-01

    The lecture begins by reviewing the various types of plant in which two phase flow occurs. Specifically, boiling plant, condensing plant and pipelines are reviewed, and the various two phase flow problems occurring in them are described. Of course, many other kinds of chemical engineering plant involve two phase flow, but are somewhat outside the scope of this lecture. This would include distillation columns, vapor-liquid separators, absorption towers etc. Other areas of industrial two phase flow which have been omitted for space reasons from this lecture are those concerned with gas/solids, liquid/solid and liquid/liquid flows. There then follows a description of some of the two phase flow processes which are relevant in industrial equipment and where special problems occur. The topics chosen are as follows: (1) pressure drop; (2) horizontal tubes - separation effects non-uniformites in heat transfer coefficient, effect of bends on dryout; (3) multicomponent mixtures - effects in pool boiling, mass transfer effects in condensation and Marangoni effects; (4) flow distribution - manifold problems in single phase flow, separation effects at a single T-junction in two phase flow and distribution in manifolds in two phase flow; (5) instability - oscillatory instability, special forms of instability in cryogenic systems; (6) nucleate boiling - effect of variability of surface, unresolved problems in forced convective nucleate boiling; and (7) shell side flows - flow patterns, cross flow boiling, condensation in cross flow

  7. A Simple Approach to Characterize Gas-Aqueous Liquid Two-phase Flow Configuration Based on Discrete Solid-Liquid Contact Electrification.

    Science.gov (United States)

    Choi, Dongwhi; Lee, Donghyeon; Kim, Dong Sung

    2015-10-14

    In this study, we first suggest a simple approach to characterize configuration of gas-aqueous liquid two-phase flow based on discrete solid-liquid contact electrification, which is a newly defined concept as a sequential process of solid-liquid contact and successive detachment of the contact liquid from the solid surface. This approach exhibits several advantages such as simple operation, precise measurement, and cost-effectiveness. By using electric potential that is spontaneously generated by discrete solid-liquid contact electrification, the configurations of the gas-aqueous liquid two-phase flow such as size of a gas slug and flow rate are precisely characterized. According to the experimental and numerical analyses on parameters that affect electric potential, gas slugs have been verified to behave similarly to point electric charges when the measuring point of the electric potential is far enough from the gas slug. In addition, the configuration of the gas-aqueous liquid two-phase microfluidic system with multiple gas slugs is also characterized by using the presented approach. For a proof-of-concept demonstration of using the proposed approach in a self-triggered sensor, a gas slug detector with a counter system is developed to show its practicality and applicability.

  8. Interfacial transport characteristics in a gas-liquid or an immiscible liquid-liquid stratified flow

    International Nuclear Information System (INIS)

    Inoue, A.; Aoki, S.; Aritomi, M.; Kozawa, Y.

    1982-01-01

    This paper is a review for an interfacial transport characteristics of mass, momentum and energy in a gas-liquid or a immiscible liquid-liquid stratified flow with wavy interface which have been studied in our division. In the experiment, a characteristic of wave motion and its effect to the turbulence near the interface as well as overall flow characteristics like pressure drop, position of the interface were investigated in an air-water, an air-mercury and a water-liquid metal stratified flow. On the other hand, several models based on the mixing length model and a two-equation model of turbulence, with special interfacial boundary conditions in which the wavy surface was regarded as a rough surface correspond to the wavy height, a source of turbulent energy equal to the wave energy and a damped-turbulence due to the surface tension, were proposed to predict the flow characteristics and the interfacial heat transfer in a fully developed and an undeveloped stratified flow and examined by the experimental data. (author)

  9. Estimation of gas wall shear stress in horizontal stratified gas-liquid pipe flow

    International Nuclear Information System (INIS)

    Newton, C.H.; Behnia, M.

    1996-01-01

    Two-phase pipe flows occur in many industrial applications, such as condensers and evaporators, chemical processing equipment, nuclear reactors, and oil pipelines. A variety of basic mechanistic flow models for predicting the pressure gradient and liquid loading characteristics of these types of flows to assist in design calculations has emerged over the past two decades, especially for the stratified and slug flow regimes. These models generally rely on a number of basic assumptions and empirical closure equations. Possibly the most notable of these relates to the evaluation of interfacial shear stresses. However, one of the most important yet least discussed assumptions used in most of these models is that the phase wall shear stresses can be accurately estimated from correlations developed for single-phase pipe flows. The object of this article is to present measurements of gas wall shear up to locations in close proximity to the gas-liquid interface for a variety of interface conditions in developed flow, and to determine the effects of the interface on average gas wall friction factors. In this context the interface may be smooth, rippled or wavy

  10. Flow measurement in two-phase (gas-liquid) systems

    International Nuclear Information System (INIS)

    Hewitt, G.F.; Whalley, P.B.

    1980-01-01

    The main methods of measuring mass flow and quality in gas-liquid flows in industrial situations are reviewed. These include gamma densitometry coupled with differential pressure devices such as crifice plates, turbine flow meters and drag screens. For each method the principle of operation, and the advantages and disadvantages, are given. Some further techniques which are currently being investigated and developed for routine use are also described briefly. Finally the detailed flow measurements possible on a particular flow pattern - annular flow - is examined. (author)

  11. Interaction of Liquid Film Flow of Direct Vessel Injection Under the Cross Directional Gas Flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han-sol; Lee, Jae-young [Handong Global University, Pohang (Korea, Republic of); Euh, Dong-Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    In order to obtain a proper scaling law of the flow, local information of the flow was investigated experimentally and also numerically. A series of experiments were conducted in the 1/20 modified linear scaled plate type test rig to analyze a liquid film from ECC water injection through the DVI nozzle to the downcomer wall. The present study investigates liquid film flow generated in a downcomer of direct vessel injection (DVI) system which is employed as an emergency core cooling (ECC) system during a loss of coolant accident in the Korea nuclear power plant APR1400. During the late reflooding, complicated multi-phase flow phenomena including the wavy film flow, film breakup, entrainment, liquid film shift due to interfacial drag and gas jet impingement occur. A confocal chromatic sensor was used to measure the local instantaneous liquid film thickness and a hydraulic jump in the film flow and boundaries of the film flow. It was found that CFD analysis results without surface tension model showed some difference with the data in surface tension dominated flow region. For the interaction between a liquid film and gas shear flow, CFD results make a good agreement with the real liquid film dynamics in the case of low film Reynolds number or low Weber number flow. In the 1/20 scaled plate type experiment and simulation, the deformed spreading profile results seem to accord with each other at the relatively low We and Re regime.

  12. Convection Study by PIV Method Within Horizontal Liquid Layer Evaporating Into Inert Gas Flow

    Directory of Open Access Journals (Sweden)

    Kreta Aleksei

    2016-01-01

    Full Text Available The paper is devoted to the experimental study of convection in a horizontal evaporating liquid layer (ethanol of limited size under the action of gas flow (air. The two-dimensional velocity field in the liquid layer is obtained using the PIV method. The existence of a vortex convective flow within a liquid layer directed towards the gas flow has been revealed.

  13. A mechanistic model of heat transfer for gas-liquid flow in vertical wellbore annuli.

    Science.gov (United States)

    Yin, Bang-Tang; Li, Xiang-Fang; Liu, Gang

    2018-01-01

    The most prominent aspect of multiphase flow is the variation in the physical distribution of the phases in the flow conduit known as the flow pattern. Several different flow patterns can exist under different flow conditions which have significant effects on liquid holdup, pressure gradient and heat transfer. Gas-liquid two-phase flow in an annulus can be found in a variety of practical situations. In high rate oil and gas production, it may be beneficial to flow fluids vertically through the annulus configuration between well tubing and casing. The flow patterns in annuli are different from pipe flow. There are both casing and tubing liquid films in slug flow and annular flow in the annulus. Multiphase heat transfer depends on the hydrodynamic behavior of the flow. There are very limited research results that can be found in the open literature for multiphase heat transfer in wellbore annuli. A mechanistic model of multiphase heat transfer is developed for different flow patterns of upward gas-liquid flow in vertical annuli. The required local flow parameters are predicted by use of the hydraulic model of steady-state multiphase flow in wellbore annuli recently developed by Yin et al. The modified heat-transfer model for single gas or liquid flow is verified by comparison with Manabe's experimental results. For different flow patterns, it is compared with modified unified Zhang et al. model based on representative diameters.

  14. Measurement of gas-liquid two-phase flow around horizontal tube bundle using SF6-water. Simulating high-pressure high-temperature gas-liquid two-phase flow of PWR/SG secondary coolant side at normal pressure

    International Nuclear Information System (INIS)

    Ishikawa, Atsushi; Imai, Ryoj; Tanaka, Takahiro

    2014-01-01

    In order to improve prediction accuracy of analysis code used for design and development of industrial products, technology had been developed to create and evaluate constitutive equation incorporated in analysis code. The experimental facility for PWR/SG U tubes part was manufactured to measure local void fraction and gas-liquid interfacial velocity with forming gas-liquid upward two-phase flow simulating high-pressure high-temperature secondary coolant (water-steam) rising vertically around horizontal tube bundle. The experimental facility could reproduce flow field having gas-liquid density ratio equivalent to real system with no heating using SF6 (Sulfur Hexafluoride) gas at normal temperature and pressure less than 1 MPa, because gas-liquid density ratio, surface tension and gas-liquid viscosity ratio were important parameters to determine state of gas-liquid two-phase flow and gas-liquid density ratio was most influential. Void fraction was measured by two different methods of bi-optical probe and conductivity type probe. Test results of gas-liquid interfacial velocity vs. apparent velocity were in good agreement with existing empirical equation within 10% error, which could confirm integrity of experimental facility and appropriateness of measuring method so as to set up original constitutive equation in the future. (T. Tanaka)

  15. Experimental Study of gas-liquid two-phase flow affected by wall surface wettability

    International Nuclear Information System (INIS)

    Takamasa, T.; Hazuku, T.; Hibiki, T.

    2008-01-01

    To evaluate the effect of wall surface wettability on the characteristics of upward gas-liquid two-phase flow in a vertical pipe, an experimental study was performed using three test pipes: an acrylic pipe, a hydrophilic pipe and a hydrophobic pipe. Basic flow characteristics such as flow patterns, pressure drop and void fraction were measured in these three pipes. In the hydrophilic pipe, a slug to churn flow transition boundary was shifted to a higher gas velocity at a given liquid velocity, whereas a churn to annular flow transition boundary was shifted to a lower gas velocity at a given liquid velocity. In the hydrophobic pipe, an inverted-churn flow regime was observed in the region where the churn flow regime was observed in the acrylic pipe, while a droplet flow regime was observed in the region where an annular flow regime was observed in the acrylic pipe. At a high gas flow rate, the mean void fraction in the hydrophobic pipe was higher than in the acrylic pipe. The effect of surface wettability on frictional pressure loss was confirmed to be insignificant under the present experimental conditions

  16. Analysis of gas-liquid metal two-phase flows using a reactor safety analysis code SIMMER-III

    International Nuclear Information System (INIS)

    Suzuki, Tohru; Tobita, Yoshiharu; Kondo, Satoru; Saito, Yasushi; Mishima, Kaichiro

    2003-01-01

    SIMMER-III, a safety analysis code for liquid-metal fast reactors (LMFRs), includes a momentum exchange model based on conventional correlations for ordinary gas-liquid flows, such as an air-water system. From the viewpoint of safety evaluation of core disruptive accidents (CDAs) in LMFRs, we need to confirm that the code can predict the two-phase flow behaviors with high liquid-to-gas density ratios formed during a CDA. In the present study, the momentum exchange model of SIMMER-III was assessed and improved using experimental data of two-phase flows containing liquid metal, on which fundamental information, such as bubble shapes, void fractions and velocity fields, has been lacking. It was found that the original SIMMER-III can suitably represent high liquid-to-gas density ratio flows including ellipsoidal bubbles as seen in lower gas fluxes. In addition, the employment of Kataoka-Ishii's correlation has improved the accuracy of SIMMER-III for gas-liquid metal flows with cap-shape bubbles as identified in higher gas fluxes. Moreover, a new procedure, in which an appropriate drag coefficient can be automatically selected according to bubble shape, was developed. Through this work, the reliability and the precision of SIMMER-III have been much raised with regard to bubbly flows for various liquid-to-gas density ratios

  17. Thermocapillary and shear driven flows in gas/liquid system in annular duct

    International Nuclear Information System (INIS)

    Gaponenko, Yu; Shevtsova, V; Nepomnyashchy, A

    2011-01-01

    We report the results of numerical study of two-phase flows in annulus for different aspect ratios obtained in the frame of the JEREMI experiment preparation. The geometry of the physical problem is a cylindrical and non-deformable liquid bridge concentrically surrounded by an annular gas channel under conditions of zero gravity. Thermocapillary (Marangoni) convection in liquid bridge of Pr = 68 is analyzed in the case when the interface is subjected to an axial gas stream. The gas flow is counter-directed with respect to the Marangoni flow. The inlet gas velocity U 0 g , temperature difference ΔT between end rods of the liquid bridge and aspect ratio are the control parameters of the system. In the case when the gas stream comes from the cold side, it cools down the interface to a temperature lower than that of the liquid beneath, and in a certain region of the parameter space that cooling causes instability due to a temperature difference in the direction, perpendicular to the interface. The present study is focused on the influence of the aspect ratio on the existence and characteristic features of the oscillatory regime.

  18. Flow chemistry: intelligent processing of gas-liquid transformations using a tube-in-tube reactor.

    Science.gov (United States)

    Brzozowski, Martin; O'Brien, Matthew; Ley, Steven V; Polyzos, Anastasios

    2015-02-17

    CONSPECTUS: The previous decade has witnessed the expeditious uptake of flow chemistry techniques in modern synthesis laboratories, and flow-based chemistry is poised to significantly impact our approach to chemical preparation. The advantages of moving from classical batch synthesis to flow mode, in order to address the limitations of traditional approaches, particularly within the context of organic synthesis are now well established. Flow chemistry methodology has led to measurable improvements in safety and reduced energy consumption and has enabled the expansion of available reaction conditions. Contributions from our own laboratories have focused on the establishment of flow chemistry methods to address challenges associated with the assembly of complex targets through the development of multistep methods employing supported reagents and in-line monitoring of reaction intermediates to ensure the delivery of high quality target compounds. Recently, flow chemistry approaches have addressed the challenges associated with reactions utilizing reactive gases in classical batch synthesis. The small volumes of microreactors ameliorate the hazards of high-pressure gas reactions and enable improved mixing with the liquid phase. Established strategies for gas-liquid reactions in flow have relied on plug-flow (or segmented flow) regimes in which the gas plugs are introduced to a liquid stream and dissolution of gas relies on interfacial contact of the gas bubble with the liquid phase. This approach confers limited control over gas concentration within the liquid phase and is unsuitable for multistep methods requiring heterogeneous catalysis or solid supported reagents. We have identified the use of a gas-permeable fluoropolymer, Teflon AF-2400, as a simple method of achieving efficient gas-liquid contact to afford homogeneous solutions of reactive gases in flow. The membrane permits the transport of a wide range of gases with significant control of the stoichiometry of

  19. Hydrodynamic boundary conditions for one-component liquid-gas flows on non-isothermal solid substrates

    KAUST Repository

    Xu, Xinpeng; Liu, Chun; Qian, Tiezheng

    2012-01-01

    profiles of liquid-gas flows on non-isothermal, heterogeneous solid substrates is still absent. The purpose of this work is to construct a continuum model for simulating the liquid-gas flows on solid surfaces that are flat and rigid, and may involve

  20. Effects of gas flow on oxidation reaction in liquid induced by He/O{sub 2} plasma-jet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Atsushi; Uchida, Giichiro, E-mail: uchida@jwri.osaka-u.ac.jp; Takenaka, Kosuke; Setsuhara, Yuichi [Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Kawasaki, Toshiyuki [Department of Mechanical and Electrical Engineering, Nippon Bunri University, Oita, Oita 870-0397 (Japan); Koga, Kazunori; Sarinont, Thapanut; Amano, Takaaki; Shiratani, Masaharu [Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Fukuoka 819-0395 (Japan)

    2015-07-28

    We present here analysis of oxidation reaction in liquid by a plasma-jet irradiation under various gas flow patterns such as laminar and turbulence flows. To estimate the total amount of oxidation reaction induced by reactive oxygen species (ROS) in liquid, we employ a KI-starch solution system, where the absorbance of the KI-starch solution near 600 nm behaves linear to the total amount of oxidation reaction in liquid. The laminar flow with higher gas velocity induces an increase in the ROS distribution area on the liquid surface, which results in a large amount of oxidation reaction in liquid. However, a much faster gas flow conversely results in a reduction in the total amount of oxidation reaction in liquid under the following two conditions: first condition is that the turbulence flow is triggered in a gas flow channel at a high Reynolds number of gas flow, which leads to a marked change of the spatial distribution of the ROS concentration in gas phase. Second condition is that the dimpled liquid surface is formed by strong gas flow, which prevents the ROS from being transported in radial direction along the liquid surface.

  1. Flow characteristics of centrifugal gas-liquid separator. Investigation with air-water two-phase flow experiment

    International Nuclear Information System (INIS)

    Yoneda, Kimitoshi; Inada, Fumio

    2004-01-01

    Air-water two-phase flow experiment was conducted to examine the basic flow characteristics of a centrifugal gas-liquid separator. Vertical transparent test section, which is 4 m in height, was used to imitate the scale of a BWR separator. Flow rate conditions of gas and liquid were fixed at 0.1 m 3 /s and 0.033 m 3 /s, respectively. Radial distributions of two-phase flow characteristics, such as void fraction, gas velocity and bubble chord length, were measured by traversing dual optical void probes in the test section, horizontally. The flow in the standpipe reached to quasi-developed state within the height-to-diameter aspect ratio H/D=10, which in turn can mean the maximum value for an ideal height design of a standpipe. The liquid film in the barrel showed a maximum thickness at 0.5 to 1 m in height from the swirler exit, which was a common result for three different standpipe length conditions, qualitatively and quantitatively. The empirical database obtained in this study would contribute practically to the validation of numerical analyses for an actual separator in a plant, and would also be academically useful for further investigations of two-phase flow in large-diameter pipes. (author)

  2. The effect of the gas-liquid density ratio on the liquid film thickness in vertical upward annular flow

    International Nuclear Information System (INIS)

    Mori, Shoji; Okuyama, Kunito

    2010-01-01

    Annular two phase flow is encountered in many industrial equipments, including flow near nuclear fuel rods in boiling water reactor (BWR). Especially, disturbance waves play important roles in the pressure drop, the generation of entrainments, and the dryout of the liquid film. Therefore, it is important to clarify the behavior of disturbance waves and base film. However, most of the previous studies have been performed under atmospheric pressure conditions that provide the properties of liquid and gas which are significantly different from those of a BWR. Therefore, the effect of properties in gas and liquid on liquid film characteristics should be clarified. In this paper we focus on the effect of gas-liquid density ratio on liquid film thickness characteristics. The experiments have been conducted at four density ratio conditions (ρ L /ρ G =763, 451, 231, and 31). As a result, it was found that liquid film thickness characteristics including the effect of liquid/gas density ratios were well correlated with a gas Weber number and the liquid Reynolds number in the wide range of experimental conditions (ρ L /ρ G : 31-763, We: 10-1800, Re L : 500-2200). (author)

  3. Dynamic Modeling Strategy for Flow Regime Transition in Gas-Liquid Two-Phase Flows

    Directory of Open Access Journals (Sweden)

    Xia Wang

    2012-12-01

    Full Text Available In modeling gas-liquid two-phase flows, the concept of flow regimes has been widely used to characterize the global interfacial structure of the flows. Nearly all constitutive relations that provide closures to the interfacial transfers in two-phase flow models, such as the two-fluid model, are flow regime dependent. Current nuclear reactor safety analysis codes, such as RELAP5, classify flow regimes using flow regime maps or transition criteria that were developed for steady-state, fully-developed flows. As two-phase flows are dynamic in nature, it is important to model the flow regime transitions dynamically to more accurately predict the two-phase flows. The present work aims to develop a dynamic modeling strategy to determine flow regimes in gas-liquid two-phase flows through introduction of interfacial area transport equations (IATEs within the framework of a two-fluid model. The IATE is a transport equation that models the interfacial area concentration by considering the creation of the interfacial area, fluid particle (bubble or liquid droplet disintegration, boiling and evaporation, and the destruction of the interfacial area, fluid particle coalescence and condensation. For flow regimes beyond bubbly flows, a two-group IATE has been proposed, in which bubbles are divided into two groups based on their size and shapes, namely group-1 and group-2 bubbles. A preliminary approach to dynamically identify the flow regimes is discussed, in which discriminators are based on the predicted information, such as the void fraction and interfacial area concentration. The flow regime predicted with this method shows good agreement with the experimental observations.

  4. About the statistical description of gas-liquid flows

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, D.; Guido-Lavalle, G.; Carrica, P. [Centro Atomico Bariloche and Instituto Balseiro (Argentina)] [and others

    1995-09-01

    Elements of the probabilistic geometry are used to derive the bubble coalescence term of the statistical description of gas liquid flows. It is shown that the Boltzmann`s hypothesis, that leads to the kinetic theory of dilute gases, is not appropriate for this kind of flows. The resulting integro-differential transport equation is numerically integrated to study the flow development in slender bubble columns. The solution remarkably predicts the transition from bubbly to slug flow pattern. Moreover, a bubbly bimodal size distribution is predicted, which has already been observed experimentally.

  5. Cavitation and gas-liquid flow in fluid machinery and devices. FED-Volume 190

    International Nuclear Information System (INIS)

    O'Hern, T.J.; Kim, J.H.; Morgan, W.B.; Furuya, O.

    1994-01-01

    Cavitation and gas-liquid two-phase flow have remained important areas in many industrial applications and constantly provided challenges for academic researchers and industrial practitioners alike. Cavitation and two-phase flow commonly occur in fluid machinery such as pumps, propellers, and fluid devices such as orifices, valves, and diffusers. Cavitation not only degrades the performance of these machines and devices but deteriorates the materials. Gas-liquid two-phase flow has also been known to degrade the performance of pumps and propellers and can often induce an instability. The industrial applications of cavitation and two-phase flow can be found in power plants, ship propellers, hydrofoils, and aerospace equipment, to name but a few. The papers presented in this volume reflect the variety and richness of cavitation and gas-liquid two-phase flow in various flow transporting components and the increasing role they play in modern and conventional technologies. Separate abstracts were prepared for 35 papers in this book

  6. Effect of surface wettability on flow patterns in vertical gas-liquid two-phase flow

    International Nuclear Information System (INIS)

    Nakamura, D.

    2005-01-01

    To examine the effect of the surface characteristics on the flow regime in two-phase flow, visualization study was performed using three test pipes, namely a no-coating pipe, a water-attracting coating pipe, a water-shedding coating pipe. Three flow regime maps were obtained based on the visual observation in the three pipes. In the water-attracting coating pipe, the slug flow-to-churn flow transition boundary was shifted to higher gas velocity at a given liquid velocity, whereas the churn flow-to-annular flow transition boundary was shifted to lower gas velocity at a given liquid velocity. In the water shedding coating pipe, the inverted-churn flow regime was observed in the region where the churn flow regime was to be observed in a no-coating pipe, whereas the droplet flow regime was observed in the region where the annular flow regime was to be observed in a no-coating pipe. The criteria for the slug flow-to-inverted-churn flow transition and the inverted-churn flow-to-droplet flow transition were modeled by force balance approaches. The modeled transition criteria could predict the observed flow transition boundaries reasonably well. (authors)

  7. Forming of film surface of very viscous liquid flowing with gas in pipes

    Directory of Open Access Journals (Sweden)

    Czernek Krystian

    2017-01-01

    Full Text Available The study presents the possible use of optoelectronic system for the measurement of the values, which are specific for hydrodynamics of two-phase gas liquid flow in vertical pipes, where a very-high-viscosity liquid forms a falling film in a pipe. The experimental method was provided, and the findings were presented and analysed for selected values, which characterize the two-phase flow. Attempt was also made to evaluate the effects of flow parameters and properties of the liquid on the gas-liquid interface value, which is decisive for the conditions of heat exchange and mass transfer in falling film equipment. The nature and form of created waves at various velocities were also described.

  8. Prediction of gas volume fraction in fully-developed gas-liquid flow in a vertical pipe

    International Nuclear Information System (INIS)

    Islam, A.S.M.A.; Adoo, N.A.; Bergstrom, D.J.; Wang, D.F.

    2015-01-01

    An Eulerian-Eulerian two-fluid model has been implemented for the prediction of the gas volume fraction profile in turbulent upward gas-liquid flow in a vertical pipe. The two-fluid transport equations are discretized using the finite volume method and a low Reynolds number κ-ε turbulence model is used to predict the turbulence field for the liquid phase. The contribution to the effective turbulence by the gas phase is modeled by a bubble induced turbulent viscosity. For the fully-developed flow being considered, the gas volume fraction profile is calculated using the radial momentum balance for the bubble phase. The model potentially includes the effect of bubble size on the interphase forces and turbulence model. The results obtained are in good agreement with experimental data from the literature. The one-dimensional formulation being developed allows for the efficient assessment and further development of both turbulence and two-fluid models for multiphase flow applications in the nuclear industry. (author)

  9. Prediction of gas volume fraction in fully-developed gas-liquid flow in a vertical pipe

    Energy Technology Data Exchange (ETDEWEB)

    Islam, A.S.M.A.; Adoo, N.A.; Bergstrom, D.J., E-mail: nana.adoo@usask.ca [University of Saskatchewan, Department of Mechanical Engineering, Saskatoon, SK (Canada); Wang, D.F. [Canadian Nuclear Laboratories, Chalk River, ON (Canada)

    2015-07-01

    An Eulerian-Eulerian two-fluid model has been implemented for the prediction of the gas volume fraction profile in turbulent upward gas-liquid flow in a vertical pipe. The two-fluid transport equations are discretized using the finite volume method and a low Reynolds number κ-ε turbulence model is used to predict the turbulence field for the liquid phase. The contribution to the effective turbulence by the gas phase is modeled by a bubble induced turbulent viscosity. For the fully-developed flow being considered, the gas volume fraction profile is calculated using the radial momentum balance for the bubble phase. The model potentially includes the effect of bubble size on the interphase forces and turbulence model. The results obtained are in good agreement with experimental data from the literature. The one-dimensional formulation being developed allows for the efficient assessment and further development of both turbulence and two-fluid models for multiphase flow applications in the nuclear industry. (author)

  10. A review on measuring methods of gas-liquid flow rates

    International Nuclear Information System (INIS)

    Minemura, Kiyoshi; Yamashita, Masato

    2000-01-01

    This paper presents a review on the state of current measuring techniques for gas-liquid multiphase flow rates. After briefly discussing the basic idea on measuring methods for single-phase and two-phase flows, existing methods for the two-phase flow rates are classified into several types, that is, with or without a homogenizing device, single or combined method of several techniques, with intrusive or non-intrusive sensors, and physical or software method. Each methods are comparatively reviewed in view of measuring accuracy and manageability. Its scope also contains the techniques developed for petroleum-gas-water flow rates. (author)

  11. Analysis of spatial and temporal spectra of liquid film surface in annular gas-liquid flow

    Science.gov (United States)

    Alekseenko, Sergey; Cherdantsev, Andrey; Heinz, Oksana; Kharlamov, Sergey; Markovich, Dmitriy

    2013-09-01

    Wavy structure of liquid film in annular gas-liquid flow without liquid entrainment consists of fast long-living primary waves and slow short-living secondary waves. In present paper, results of spectral analysis of this wavy structure are presented. Application of high-speed LIF technique allowed us to perform such analysis in both spatial and temporal domains. Power spectra in both domains are characterized by one-humped shape with long exponential tail. Influence of gas velocity, liquid Reynolds number, liquid viscosity and pipe diameter on frequency of the waves is investigated. When gravity effect is much lesser than the shear stress, similarity of power spectra at different gas velocities is observed. Using combination of spectral analysis and identification of characteristic lines of primary waves, frequency of generation of secondary waves by primary waves is measured.

  12. Film thickness in gas-liquid two-phase flow, (2)

    International Nuclear Information System (INIS)

    Sekoguchi, Kotohiko; Fukano, Toru; Kawakami, Yasushi; Shimizu, Hideo.

    1977-01-01

    The effect of four rectangular obstacles inserted into a circular tube has been studied in gas-liquid two-phase flow. The obstacles are set on the inner wall of the tube, and the ratio of the opening is 0.6. The water film flows partially through the obstacles. The minimum thickness of water film was measured in relation to flow speed. The serious effect of the obstacles was seen against the formation of water film, and drainage under the obstacles and backward flow play important roles. Since water film can flow partially through the obstacles, the film in case of the rectangular obstacles in thicker than that in case of an orifice when the gas flow speed was slower than 5 m/s. However, when the gas flow speed is over 5 m/s, the film thickness was thinner. The minimum film thickness of downstream of the obstacles was almost same as that in case of no obstacle. The minimum film thickness of up stream depends on the location of measurement due to the effect of drainage. (Kato, T.)

  13. Numerical Simulation and Analysis of Gas-Liquid Flow in a T-Junction Microchannel

    Directory of Open Access Journals (Sweden)

    Hongtruong Pham

    2012-01-01

    Full Text Available Gas-liquid flow in microchannels is widely used in biomedicine, nanotech, sewage treatment, and so forth. Particularly, owing to the high qualities of the microbubbles and spheres produced in microchannels, it has a great potential to be used in ultrasound imaging and controlled drug release areas; therefore, gas-liquid flow in microchannels has been the focus in recent years. In this paper, numerical simulation of gas-liquid flows in a T-junction microchannel was carried out with computational fluid dynamics (CFD software FLUENT and the Volume-of-Fluid (VOF model. The distribution of velocity, pressure, and phase of fluid in the microchannel was obtained, the pressure distribution along the channel walls was analyzed in order to give a better understanding on the formation of microbubbles in the T-junction microchannel.

  14. Film behaviour of vertical gas-liquid flow in a large diameter pipe

    OpenAIRE

    Zangana, Mohammed Haseeb Sedeeq

    2011-01-01

    Gas-liquid flow commonly occurs in oil and gas production and processing system. Large diameter vertical pipes can reduce pressure drops and so minimize operating costs. However, there is a need for research on two-phase flow in large diameter pipes to provide confidence to designers of equipments such as deep water risers. In this study a number of experimental campaigns were carried out to measure pressure drop, liquid film thickness and wall shear in 127mm vertical pipe. Total pressur...

  15. Studies of Two-Phase Gas-Liquid Flow in Microgravity. Ph.D. Thesis, Dec. 1994

    Science.gov (United States)

    Bousman, William Scott

    1995-01-01

    Two-phase gas-liquid flows are expected to occur in many future space operations. Due to a lack of buoyancy in the microgravity environment, two-phase flows are known to behave differently than those in earth gravity. Despite these concerns, little research has been conducted on microgravity two-phase flow and the current understanding is poor. This dissertation describes an experimental and modeling study of the characteristics of two-phase flows in microgravity. An experiment was operated onboard NASA aircraft capable of producing short periods of microgravity. In addition to high speed photographs of the flows, electronic measurements of void fraction, liquid film thickness, bubble and wave velocity, pressure drop and wall shear stress were made for a wide range of liquid and gas flow rates. The effects of liquid viscosity, surface tension and tube diameter on the behavior of these flows were also assessed. From the data collected, maps showing the occurrence of various flow patterns as a function of gas and liquid flow rates were constructed. Earth gravity two-phase flow models were compared to the results of the microgravity experiments and in some cases modified. Models were developed to predict the transitions on the flow pattern maps. Three flow patterns, bubble, slug and annular flow, were observed in microgravity. These patterns were found to occur in distinct regions of the gas-liquid flow rate parameter space. The effect of liquid viscosity, surface tension and tube diameter on the location of the boundaries of these regions was small. Void fraction and Weber number transition criteria both produced reasonable transition models. Void fraction and bubble velocity for bubble and slug flows were found to be well described by the Drift-Flux model used to describe such flows in earth gravity. Pressure drop modeling by the homogeneous flow model was inconclusive for bubble and slug flows. Annular flows were found to be complex systems of ring-like waves and a

  16. Response of small pitot tubes in gas-liquid flows

    International Nuclear Information System (INIS)

    Davis, M.R.

    1980-01-01

    The pressure rise experienced by a pitot tube immersed in a bubbly gas-liquid mixture flow exceeds that predicted by homogeneous flow analysis under conditions where the pitot is smaller than the mean bubble size. A systematic dependence of the deviation from homogeneous flow analysis exists, depending upon the mixture void fraction. A maximum effect is observed at a void fraction of 0.60, where the pressure rise was found to be 1.73 times the predicted stagnation pressure rise or 0.87 of the mixture momentum flux density. The magnitude of these effects is comparable with similar effects reported elsewhere for gas/solid mixture flow due to relative motion between phases in the vicinity of the sensing probe tip. (orig.)

  17. Gas-liquid mass transfer in a cross-flow hollow fiber module : Analytical model and experimental validation

    NARCIS (Netherlands)

    Dindore, V. Y.; Versteeg, G. F.

    2005-01-01

    The cross-flow operation of hollow fiber membrane contactors offers many advantages and is preferred over the parallel-flow contactors for gas-liquid mass transfer operations. However, the analysis of such a cross-flow membrane gas-liquid contactor is complicated due to the change in concentrations

  18. Comparison of differential pressure model based on flow regime for gas/liquid two-phase flow

    International Nuclear Information System (INIS)

    Dong, F; Zhang, F S; Li, W; Tan, C

    2009-01-01

    Gas/liquid two-phase flow in horizontal pipe is very common in many industry processes, because of the complexity and variability, the real-time parameter measurement of two-phase flow, such as the measurement of flow regime and flow rate, becomes a difficult issue in the field of engineering and science. The flow regime recognition plays a fundamental role in gas/liquid two-phase flow measurement, other parameters of two-phase flow can be measured more easily and correctly based on the correct flow regime recognition result. A multi-sensor system is introduced to make the flow regime recognition and the mass flow rate measurement. The fusion system is consisted of temperature sensor, pressure sensor, cross-section information system and v-cone flow meter. After the flow regime recognition by cross-section information system, comparison of four typical differential pressure (DP) models is discussed based on the DP signal of v-cone flow meter. Eventually, an optimum DP model has been chosen for each flow regime. The experiment result of mass flow rate measurement shows it is efficient to classify the DP models by flow regime.

  19. Using artificial intelligence to improve identification of nanofluid gas-liquid two-phase flow pattern in mini-channel

    Science.gov (United States)

    Xiao, Jian; Luo, Xiaoping; Feng, Zhenfei; Zhang, Jinxin

    2018-01-01

    This work combines fuzzy logic and a support vector machine (SVM) with a principal component analysis (PCA) to create an artificial-intelligence system that identifies nanofluid gas-liquid two-phase flow states in a vertical mini-channel. Flow-pattern recognition requires finding the operational details of the process and doing computer simulations and image processing can be used to automate the description of flow patterns in nanofluid gas-liquid two-phase flow. This work uses fuzzy logic and a SVM with PCA to improve the accuracy with which the flow pattern of a nanofluid gas-liquid two-phase flow is identified. To acquire images of nanofluid gas-liquid two-phase flow patterns of flow boiling, a high-speed digital camera was used to record four different types of flow-pattern images, namely annular flow, bubbly flow, churn flow, and slug flow. The textural features extracted by processing the images of nanofluid gas-liquid two-phase flow patterns are used as inputs to various identification schemes such as fuzzy logic, SVM, and SVM with PCA to identify the type of flow pattern. The results indicate that the SVM with reduced characteristics of PCA provides the best identification accuracy and requires less calculation time than the other two schemes. The data reported herein should be very useful for the design and operation of industrial applications.

  20. Structure of the gas-liquid annular two-phase flow in a nozzle section

    International Nuclear Information System (INIS)

    Yoshida, Kenji; Kataoka, Isao; Ohmori, Syuichi; Mori, Michitsugu

    2006-01-01

    Experimental studies on the flow behavior of gas-liquid annular two-phase flow passing through a nozzle section were carried out. This study is concerned with the central steam jet injector for a next generation nuclear reactor. In the central steam jet injector, steam/water annular two-phase flow is formed at the mixing nozzle. To make an appropriate design and to establish the high-performance steam injector system, it is very important to accumulate the fundamental data of the thermo-hydro dynamic characteristics of annular flow passing through a nozzle section. On the other hand, the transient behavior of multiphase flow, in which the interactions between two-phases occur, is one of the most interesting scientific issues and has attracted research attention. In this study, the transient gas-phase turbulence modification in annular flow due to the gas-liquid phase interaction is experimentally investigated. The annular flow passing through a throat section is under the transient state due to the changing cross sectional area of the channel and resultantly the superficial velocities of both phases are changed compared with a fully developed flow in a straight pipe. The measurements for the gas-phase turbulence were precisely performed by using a constant temperature hot-wire anemometer, and made clear the turbulence structure such as velocity profiles, fluctuation velocity profiles. The behavior of the interfacial waves in the liquid film flow such as the ripple or disturbance waves was also observed. The measurements for the liquid film thickness by the electrode needle method were also performed to measure the base film thickness, mean film thickness, maximum film thickness and wave height of the ripple or the disturbance waves. (author)

  1. The use of a low-cost gas-liquid flow meter to monitor severe slugging

    DEFF Research Database (Denmark)

    Andreussi, Paolo; Bonizzi, Marco; Ciandri, Paolo

    2017-01-01

    A very simple, low-cost gas-liquid flow meter that only employs conventional field instrumentation has been used to monitor severe slugging occurring at the exit of a vertical pipe. This meter was originally developed for conventional oil field applications [1] and is based on the readings...... method to monitor severe slugging by means of low cost instrumentation, in particular, by replacing a cumbersome instrument such as a gamma-densitometer with a differential pressure transmitter. In field operation, the multiphase orifice used in these experiments can be replaced by a calibrated control...... of a multiphase orifice and the pressure drops of the gas-liquid mixture flowing in a vertical section of the pipe. Liquid and gas flow rates have been determined by means of semi-empirical equations developed for the specific set of flow parameters (geometry, flow rates, physical properties) adopted in a series...

  2. Two-Phase Gas-Liquid Flow Structure Characteristics under Periodic Cross Forces Action

    Directory of Open Access Journals (Sweden)

    V. V. Perevezentsev

    2015-01-01

    Full Text Available The article presents a study of two-phase gas-liquid flow under the action of periodic cross forces. The work objective is to obtain experimental data for further analysis and have structure characteristics of the two-phase flow movement. For research, to obtain data without disturbing effect on the flow were used optic PIV (Particle Image Visualization methods because of their noninvasiveness. The cross forces influence was provided by an experimental stand design to change the angular amplitudes and the periods of channel movement cycle with two-phase flow. In the range of volume gas rates was shown a water flow rate versus the inclination angle of immovable riser section and the characteristic angular amplitudes and periods of riser section inclination cycle under periodic cross forces. Data on distribution of average water velocity in twophase flow in abovementioned cases were also obtained. These data allowed us to draw a conclusion that a velocity distribution depends on the angular amplitude and on the period of the riser section roll cycle. This article belongs to publications, which study two-phase flows with no disturbing effect on them. Obtained data give an insight into understanding a pattern of twophase gas-liquid flow under the action of periodic cross forces and can be used to verify the mathematical models of the CFD thermo-hydraulic codes. In the future, the work development expects taking measurements with more frequent interval in the ranges of angular amplitudes and periods of the channel movement cycle and create a mathematical model to show the action of periodic cross forces on two-phase gas-liquid flow.

  3. Numerical simulation for gas-liquid two-phase flow in pipe networks

    International Nuclear Information System (INIS)

    Li Xiaoyan; Kuang Bo; Zhou Guoliang; Xu Jijun

    1998-01-01

    The complex pipe network characters can not directly presented in single phase flow, gas-liquid two phase flow pressure drop and void rate change model. Apply fluid network theory and computer numerical simulation technology to phase flow pipe networks carried out simulate and compute. Simulate result shows that flow resistance distribution is non-linear in two phase pipe network

  4. Local studies in horizontal gas-liquid slug flow

    International Nuclear Information System (INIS)

    Sharma, S.; Lewis, S.; Kojasoy, G.

    1998-01-01

    The local axial velocity profile development in a horizontal air-water slug flow-pattern was experimentally investigated by simultaneously using two hot-film anemometers. One of the probes was exclusively used as phase identifier while the other probe was traversed for local velocity measurements. It was shown that the velocity rapidly develops into asymmetric but nearly fully-developed profiles within the liquid slugs whereas the velocity never develops into quasi-fully-developed profiles within the liquid layer underneath passing gas slugs. Transient nature of velocity at a given location was demonstrated. (author)

  5. Film thickness in gas-liquid two-phase flow, (4)

    International Nuclear Information System (INIS)

    Fukano, Toru; Sekoguchi, Kotohiko; Kawakami, Yasushi; Shimizu, Hideo.

    1979-01-01

    This paper reports in detail on the thinning process of water film by means of the drainage that appears directly under an obstacle inserted against the flow into the gas-liquid two-phase flow in a tube. The equipment is the same as that used for the first study, in which the orifice type obstacle of 5 mm long having the area ratio of 0.235 was used. This obstacle is the one for which the most significant drainage was observed in the previous study. The change of liquid film in course of time was measured by the constant current method as described before. First, the premising conditions and duration of the drainage are considered. In the thinning by drainage, water film became about 0.1 mm at the early stage of 0.1 sec from its start, then the whole water film became the flow governed by viscosity (called viscous water film). After this state, the film became thinner very slowly. The viscous film is thicker as it is apart farther from the obstacle. If the flow conditions show significant drainage, the duration of drainage directly under the obstacle is nearly equal to the passing time of gas slug. When the thinning of water film is accelerated by drainage, it might cause the possible disappearance of water film when gas slug passes, even if the thermal load is comparatively low. (Wakatsuki, Y.)

  6. Heat transfer characteristics of liquid-gas Taylor flows incorporating microencapsulated phase change materials

    International Nuclear Information System (INIS)

    Howard, J A; Walsh, P A

    2014-01-01

    This paper presents an investigation on the heat transfer characteristics associated with liquid-gas Taylor flows in mini channels incorporating microencapsulated phase change materials (MPCM). Taylor flows have been shown to result in heat transfer enhancements due to the fluid recirculation experienced within liquid slugs which is attributable to the alternating liquid slug and gas bubble flow structure. Microencapsulated phase change materials (MPCM) also offer significant potential with increased thermal capacity due to the latent heat required to cause phase change. The primary aim of this work was to examine the overall heat transfer potential associated with combining these two novel liquid cooling technologies. By investigating the local heat transfer characteristics, the augmentation/degradation over single phase liquid cooling was quantified while examining the effects of dimensionless variables, including Reynolds number, liquid slug length and gas void fraction. An experimental test facility was developed which had a heated test section and allowed MPCM-air Taylor flows to be subjected to a constant heat flux boundary condition. Infrared thermography was used to record high resolution experimental wall temperature measurements and determine local heat transfer coefficients from the thermal entrance point. 30.2% mass particle concentration of the MPCM suspension fluid was examined as it provided the maximum latent heat for absorption. Results demonstrate a significant reduction in experimental wall temperatures associated with MPCM-air Taylor flows when compared with the Graetz solution for conventional single phase coolants. Total enhancement in the thermally developed region is observed to be a combination of the individual contributions due to recirculation within the liquid slugs and also absorption of latent heat. Overall, the study highlights the potential heat transfer enhancements that are attainable within heat exchange devices employing MPCM

  7. Gas–liquid flow in stirred reactors: Trailing vortices and gas accumulation behind impeller blades

    NARCIS (Netherlands)

    Ranade, V.; Deshpande, Vaibhav R.

    1999-01-01

    In a gas–liquid stirred reactor, gas tends to accumulate in low-pressure regions behind the impeller blades. Such gas accumulation significantly alters impeller performance characteristics. We have computationally investigated gas–liquid flow generated by a Rushton (disc) turbine. Rotating Rushton

  8. A flow reactor setup for photochemistry of biphasic gas/liquid reactions

    Directory of Open Access Journals (Sweden)

    Josef Schachtner

    2016-08-01

    Full Text Available A home-built microreactor system for light-mediated biphasic gas/liquid reactions was assembled from simple commercial components. This paper describes in full detail the nature and function of the required building elements, the assembly of parts, and the tuning and interdependencies of the most important reactor and reaction parameters. Unlike many commercial thin-film and microchannel reactors, the described set-up operates residence times of up to 30 min which cover the typical rates of many organic reactions. The tubular microreactor was successfully applied to the photooxygenation of hydrocarbons (Schenck ene reaction. Major emphasis was laid on the realization of a constant and highly reproducible gas/liquid slug flow and the effective illumination by an appropriate light source. The optimized set of conditions enabled the shortening of reaction times by more than 99% with equal chemoselectivities. The modular home-made flow reactor can serve as a prototype model for the continuous operation of various other reactions at light/liquid/gas interfaces in student, research, and industrial laboratories.

  9. Boiling, condensation, and gas-liquid flow

    International Nuclear Information System (INIS)

    Whalley, P.B.

    1987-01-01

    Heat transfer phenomena involving boiling and condensation are an important aspect of engineering in the power and process industries. This book, aimed at advanced first-degree and graduate students in mechanical and chemical engineering, deals with these phenomena in detail. The first part of the book describes gas-liquid two-phase flow, as a necessary preliminary to the later discussion of heat transfer and change of phase. A detailed section on calculation methods shows how theory can be put to practical use, and there are also descriptions of some of the equipment and plant used in the process and power industries

  10. Experimental study of gas-liquid flow local characteristics in rectangular microchannel

    Directory of Open Access Journals (Sweden)

    Bartkus German

    2017-01-01

    Full Text Available Using high-speed video recording and the method of dual laser scanning the gas-liquid flow was investigated in a rectangular microchannel with an aspect ratio of 0.74 (cross section 269×362 μm. The T-mixer was used at the channel’s inlet for the two-phase flow formation. The peculiarity of this work is using a number of liquids (ethanol, distilled water, 40% aqueous ethanol with different physical properties, including surface tension, viscosity, and density, with nitrogen. Experiments were carried out for the vertically upward and horizontal flow. Using laser scanning method the maps of flow patterns were obtained for all mixtures.

  11. Local Nusselt number enhancement during gas-liquid Taylor bubble flow in a square mini-channel: An experimental study

    International Nuclear Information System (INIS)

    Majumder, Abhik; Mehta, Balkrishna; Khandekar, Sameer

    2013-01-01

    Taylor bubble flow takes place when two immiscible fluids (liquid-liquid or gas-liquid) flow inside a tube of capillary dimensions within specific range of volume flow ratios. In the slug flows where gas and liquid are two different phases, liquid slugs are separated by elongated Taylor bubbles. This singular flow pattern is observed in many engineering mini-/micro-scale devices like pulsating heat pipes, gas-liquid-solid monolithic reactors, micro-two-phase heat exchangers, digital micro-fluidics, micro-scale mass transfer process, fuel cells, etc. The unique and complex flow characteristics require understanding on local, as well as global, spatio-temporal scales. In the present work, the axial stream-wise profile of the fluid and wall temperature for air-water (i) isolated single Taylor bubble and, (ii) a train of Taylor bubbles, in a horizontal square channel of size 3.3 mm x 3.3 mm x 350 mm, heated from the bottom (heated length = 175 mm), with the other three sides kept insulated, are reported at different gas volume flow ratios. The primary aim is to study the enhancement of heat transfer due to the Taylor bubble train flow, in comparison with thermally developing single-phase flows. Intrusion of a bubble in the liquid flow drastically changes the local temperature profiles. The axial distribution of time-averaged local Nusselt number (Nu z ) shows that Taylor bubble train regime increases the transport of heat up to 1.2-1.6 times more as compared with laminar single-phase liquid flow. In addition, for a given liquid flow Reynolds number, the heat transfer enhancement is a function of the geometrical parameters of the unit cell, i.e., the length of adjacent gas bubble and water plug. (authors)

  12. Characterising gas behaviour during gas-liquid co-current up-flow in packed beds using magnetic resonance imaging

    OpenAIRE

    Collins, James HP; Sederman, Andrew John; Gladden, Lynn Faith; Afeworki, Mobae; Kushnerick, J Douglas; Thomann, Hans

    2016-01-01

    Magnetic resonance (MR) imaging techniques have been used to study gas phase dynamics during co-current up-flow in a column of inner diameter 43 mm, packed with spherical non-porous elements of diameters of 1.8, 3 and 5 mm. MR measurements of gas hold-up, bubble-size distribution, and bubble-rise velocities were made as a function of flow rate and packing size. Gas and liquid flow rates were studied in the range of 20–250 cm3 s−1 and 0–200 cm3 min−1, respectively. The gas hold-up within the b...

  13. Unstable well behaviour in gas well liquid loading

    NARCIS (Netherlands)

    Belfroid, S.P.C.; Wijhe, A. van

    2017-01-01

    Liquid loading is the mechanism that is associated with increased liquid hold-up and liquid back flow at lower gas flow rates in gas production wells. In laboratory, most liquid loading experiments are performed at fixed gas and liquid rates (mass flow controlled). In the field, the well behavior is

  14. Experimental investigation of two-phase gas-liquid flow in microchannel with T-junction

    Science.gov (United States)

    Bartkus, German; Kozulin, Igor; Kuznetsov, Vladimir

    2017-10-01

    Using high-speed video recording and the method of dual laser scanning the gas-liquid flow was investigated in rectangular microchannels with an aspect ratio of 2.35 and 1.26. Experiments were earned out for the vertical flow of ethanol-nitrogen mixture in a microchannel with a cross section of 553×235 µm and for the horizontal flow of water-nitrogen mixture in a microchannel with a cross section of 315×250 µm. The T-mixer was used at the channel's inlet for gas-liquid flow formation. It was observed that elongated bubble, transition, and annular flows are the main regimes for a microchannel with a hydraulic diameter substantially less than the capillary constant. Using laser scanning, the maps of flow regimes for ethanol-nitrogen and water-nitrogen mixtures were obtained and discussed.

  15. Simulation of the Two-Phase LiquidGas Flow through Ultrasonic Transceivers Application in Ultrasonic Tomography

    Directory of Open Access Journals (Sweden)

    Zulkarnay Zakaria

    2010-01-01

    Full Text Available In this paper, ultrasonic transmission mode tomography was used to visualize the two phase liquid/gas flow in a pipe/vessel. The sensing element consists of 8, 16 and 32 units ultrasonic transceivers were used to cover the pipe cross-section at different time. The motivation of this paper is to analyze the optimum numbers of transceivers which can give the best performance in providing better image of the two phase liquid/gas flow. This paper also details the development of the system including the ultrasonic transduction circuits, the electronic measurement circuits, the data acquisition system and the image reconstruction techniques. Ten conditions of liquid-gas flow have been simulated. The system was found capable of visualizing the internal characteristics and provides the concentration profile for the corresponding liquid and gas phases while the 32 transceivers has provided the best image for the ten conditions applied.

  16. Gas-liquid two-phase flow behavior in terrain-inclined pipelines for gathering transport system of wet natural gas

    DEFF Research Database (Denmark)

    Yang, Yan; Li, Jingbo; Wang, Shuli

    2018-01-01

    The Volume of Fluid method and Re-Normalisation Group (RNG) k-ε turbulence model were employed to predict the gas-liquid two-phase flow in a terrain-inclined pipeline with deposited liquids. The simulation was carried out in a 22.5 m terrain-inclined pipeline with a 150 mm internal diameter...... on the liquid level under the suction force which caused by the negative pressure around the elbow, and then it touched to the top of the pipe. When the liquid blocked the pipe, the pressure drop between the upstream and downstream of the elbow increased with the increase of the gas velocity. At larger gas...

  17. Visualization and measurement of liquid velocity field of gas-liquid metal two-phase flow using neutron radiography

    International Nuclear Information System (INIS)

    Saito, Yasushi; Suzuki, Tohru; Matsubayashi, Masahito

    2000-01-01

    In a core melt accident of a fast breeder reactor, a possibility of re-criticality is anticipated in the molten fuel-steel mixture pool. One of the mechanisms to suppress the re-criticality is the boiling of steel in the molten fuel-steel mixture pool because of the negative void reactivity effect. To evaluate the reactivity change due to boiling, it is necessary to know the characteristics of gas-liquid two-phase flow in the molten fuel-steel mixture pool. For this purpose, boiling bubbles in a molten fuel-steel mixture pool were simulated by adiabatic gas bubbles in a liquid metal pool to study the basic characteristics of gas-liquid metal two-phase mixture. Visualization of the two-phase mixture and measurements of liquid phase velocity and void fraction were conducted by using neutron radiography and image processing techniques. From these measurements, the basic characteristics of gas-liquid metal two-phase mixture were clarified. (author)

  18. Measurement of gas-liquid two-phase flow in micro-pipes by a capacitance sensor.

    Science.gov (United States)

    Ji, Haifeng; Li, Huajun; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing

    2014-11-26

    A capacitance measurement system is developed for the measurement of gas-liquid two-phase flow in glass micro-pipes with inner diameters of 3.96, 2.65 and 1.56 mm, respectively. As a typical flow regime in a micro-pipe two-phase flow system, slug flow is chosen for this investigation. A capacitance sensor is designed and a high-resolution and high-speed capacitance measurement circuit is used to measure the small capacitance signals based on the differential sampling method. The performance and feasibility of the capacitance method are investigated and discussed. The capacitance signal is analyzed, which can reflect the voidage variation of two-phase flow. The gas slug velocity is determined through a cross-correlation technique using two identical capacitance sensors. The simulation and experimental results show that the presented capacitance measurement system is successful. Research work also verifies that the capacitance sensor is an effective method for the measurement of gas liquid two-phase flow parameters in micro-pipes.

  19. Analyses of liquid-gas two-phase flow in fermentation tanks

    International Nuclear Information System (INIS)

    Toi, Takashi; Serizawa, Akimi; Takahashi, Osamu; Kawara, Zensaku; Gofuku, Akio; Kataoka, Isao.

    1993-01-01

    The understanding of two-phase flow is one of the important problems for both design and safety analyses of various engineering systems. For example, the flow conditions in beer fermentation tanks have an influence on the quality of production and productivity of tank. In this study, a two-dimensional numerical calculation code based on the one-pressure two-fluid model is developed to understand the circulation structure of low quality liquid-gas two-phase flows induced by bubble plume in a tank. (author)

  20. INTERACTION OF LIQUID FLAT SCREENS WITH GAS FLOW RESTRICTED BY CHANNEL WALLS

    Directory of Open Access Journals (Sweden)

    S. T. Aksentiev

    2005-01-01

    Full Text Available The paper gives description of physical pattern of liquid screen interaction that are injected from the internal walls of a rectangular channel with gas flow. Criterion dependences for determination of intersection coordinates of external boundaries with longitudinal channel axis and factor of liquid screen head resistance.

  1. Visualization and measurement of gas-liquid metal two-phase flow with large density difference using thermal neutrons as microscopic probes

    International Nuclear Information System (INIS)

    Mishima, K.; Hibiki, T.; Saito, Y.; Nishihara, H.; Tobita, Y.; Konishi, K.; Matsubayashi, M.

    1999-01-01

    In a core melt accident of a fast breeder reactor, there is a possibility of boiling of the fuel-steel mixture in the containment pool. In relation to safety evaluation on severe accident, it is indispensable to evaluate the possibility of re-criticality of melted core. Gas-liquid two-phase flow with a large liquid-to-gas density ratio is formed due to the boiling of fuel-steel mixture. Although it is anticipated that the large density ratio may affect the basic characteristics of two-phase flow, little work has been performed so far on two-phase flow with a large liquid-to-gas density ratio. In this study, visualization and void fraction measurement of gas-liquid metal two-phase flow were performed by using neutron radiography and image processing techniques. Then, the effect of large density difference between gas and liquid phases on the basic flow characteristics of two-phase flow was clarified

  2. multiUQ: An intrusive uncertainty quantification tool for gas-liquid multiphase flows

    Science.gov (United States)

    Turnquist, Brian; Owkes, Mark

    2017-11-01

    Uncertainty quantification (UQ) can improve our understanding of the sensitivity of gas-liquid multiphase flows to variability about inflow conditions and fluid properties, creating a valuable tool for engineers. While non-intrusive UQ methods (e.g., Monte Carlo) are simple and robust, the cost associated with these techniques can render them unrealistic. In contrast, intrusive UQ techniques modify the governing equations by replacing deterministic variables with stochastic variables, adding complexity, but making UQ cost effective. Our numerical framework, called multiUQ, introduces an intrusive UQ approach for gas-liquid flows, leveraging a polynomial chaos expansion of the stochastic variables: density, momentum, pressure, viscosity, and surface tension. The gas-liquid interface is captured using a conservative level set approach, including a modified reinitialization equation which is robust and quadrature free. A least-squares method is leveraged to compute the stochastic interface normal and curvature needed in the continuum surface force method for surface tension. The solver is tested by applying uncertainty to one or two variables and verifying results against the Monte Carlo approach. NSF Grant #1511325.

  3. Two-phase gas bubble-liquid boundary layer flow along vertical and inclined surfaces

    International Nuclear Information System (INIS)

    Cheung, F.B.; Epstein, M.

    1985-01-01

    The behavior of a two-phase gas bubble-liquid boundary layer along vertical and inclined porous surfaces with uniform gas injection is investigated experimentally and analytically. Using argon gas and water as the working fluids, a photographical study of the two-phase boundary layer flow has been performed for various angles of inclination ranging from 45 0 to 135 0 and gas injection rates ranging from 0.01 to 0.1 m/s. An integral method has been employed to solve the system of equations governing the two-phase motion. The effects of the gas injection rate and the angle of inclination on the growth of the boundary layer have been determined. The predicted boundary layer thickness is found to be in good agreement with the experimental results. The calculated axial liquid velocity and the void fraction in the two-phase region are also presented along with the observed flow behavior

  4. Cooling of a microchannel with thin evaporating liquid film sheared by dry gas flow

    Science.gov (United States)

    Kabova, Yu O.; Kuznetsov, V. V.

    2017-11-01

    A joint motion of thin liquid film and dry gas in a microchannel is investigated numerically at different values of initial concentration of the liquid vapor in the gas phase, taking into account the evaporation process. Major factors affecting the temperature distribution in the liquid and the gas phases are as follows: transfer of heat by liquid and gas flows, heat loses due to evaporation, diffusion heat exchange. Comparisons of the numerical results for the case of the dry gas and for the case of equilibrium concentration of vapor in the gas have been carried out. It is shown that use of dry gas enhances the heat dissipation from the heater. It is found out that not only intense evaporation occurs near the heating areas, but also in both cases vapor condensation takes place below the heater in streamwise direction.

  5. Pigging analysis for gas-liquid two phase flow in pipelines

    International Nuclear Information System (INIS)

    Kohda, K.; Suzukawa, Y.; Furukawa, H.

    1988-01-01

    A new method to analyze transient phenomena caused by pigging in gas-liquid two-phase flow is developed. During pigging, a pipeline is divided into three sections by two moving boundaries, namely the pig and the leading edge of the liquid slug in front of the pig. The basic equations are mass, momentum and energy conservation equations. The boundary conditions at the moving boundaries are determined from the mass conservation across the boundaries, etc. A finite difference method is used to solve the equations numerically. The method described above is also capable of analyzing transient two-phase flow caused by pressure and flow rate changes. Thus the over-all analysis of transient two-phase flow in pipelines becomes possible. A series of air-water two-phase flow pigging experiments was conducted using 105.3 mm diameter and 1436.5 m long test pipeline. The agreement between the measured and the calculated results is very good

  6. Visualization for gas-liquid two-phase flow using wire mesh tomography

    International Nuclear Information System (INIS)

    Motegi, Yuichi; Wanjiraniran, Weerin; Kikura, Hiroshige; Aritomi, Masanori; Yamauchi, Toyoaki

    2003-01-01

    Wire Mesh Tomography (WMT), which is system to measure two-phase flow, has been developed in our laboratory. Measurement principle of WMT is detecting conductivity difference between gas and liquid. WMT measures void fraction as raw date, and calculates gas velocity and bubble volume etc. In this paper, this measurement technique was applied to vertical circular pipe of 50 mm diameter and about 7 m heights. New Wire Mesh Sensor (WMS), which is measurement part of WMT, for circular pipe, have been made. When experiment was performed, superficial gas and water velocity. The effect of each flow parameter was found for void fraction, true gas velocity and bubble volume and the results was in good agreement with the past research, qualitatively. (author)

  7. Local gas- and liquid-phase measurements for air-water two-phase flows in a rectangular channel

    International Nuclear Information System (INIS)

    Zhou, X.; Sun, X.; Williams, M.; Fu, Y.; Liu, Y.

    2014-01-01

    Local gas- and liquid-phase measurements of various gas-liquid two-phase flows, including bubbly, cap-bubbly, slug, and churn-turbulent flows, were performed in an acrylic vertical channel with a rectangular cross section of 30 mm x 10 mm and height of 3.0 m. All the measurements were carried out at three measurement elevations along the flow channel, with z/D h = 9, 72, and 136, respectively, to study the flow development. The gas-phase velocity, void fraction, and bubble number frequency were measured using a double-sensor conductivity probe. A high-speed imaging system was utilized to perform the flow regime visualization and to provide additional quantitative information of the two-phase flow structure. An image processing scheme was developed to obtain the gas-phase velocity, void fraction, Sauter mean diameter, bubble number density, and interfacial area concentration. The liquid-phase velocity and turbulence measurements were conducted using a particle image velocimetry-planar laser-induced fluorescence (PIV-PLIF) system, which enables whole-field and high-resolution data acquisition. An optical phase separation method, which uses fluorescent particles and optical filtration technique, is adopted to extract the velocity information of the liquid phase. An image pre-processing scheme is imposed on the raw PIV images acquired to remove noises due to the presence of bubble residuals and optically distorted particles in the images captured by the PIV-PLIF system. Due to the better light access and less bubble distortion in the narrow rectangular channel, the PIV-PLIF system were able to perform reasonably well in flows of even higher void fractions as compared to the situations with circular pipe test sections. The flow conditions being studied covered various flow regime transitions, void fractions, and liquid-phase flow Reynolds numbers. The obtained experimental data can also be used to validate two-phase CFD results. (author)

  8. Experimental and numerical investigation of stratified gas-liquid flow in inclined circular pipes

    International Nuclear Information System (INIS)

    Faccini, J.L.H.; Sampaio, P.A.B. de; Botelho, M.H.D.S.; Cunha, M.V.; Cunha Filho, J.S.; Su, J.

    2012-01-01

    In this paper, a stratified gas-liquid flow is experimentally and numerically investigated. Two measurement techniques, namely an ultrasonic technique and a visualization technique, are applied on an inclined circular test section using a fast single transducer pulse-echo technique and a high-speed camera. A numerical model is employed to simulate the stratified gas-liquid flow, formed by a system of non-linear differential equations consisting of the Reynolds averaged Navier-Stokes equations with the κ-ω turbulence model. The test section used in this work is comprised mainly of a transparent circular pipe with inner diameter 1 inch, and inclination angles varying from -2.5 to -10.0 degrees. Numerical solutions are obtained for the liquid height as a function of inclination angles, and compared with our own experimental data. (author)

  9. Direct numerical simulation of stratified gas-liquid flow

    International Nuclear Information System (INIS)

    Lombardi, P.; De Angelis, V.; Banerjee, S.

    1996-01-01

    Interactions through an interface between two turbulent flows play an important role in many environmental and industrial problems, e.g. in determining the coupling fluxes of heat mass and momentum, between the ocean and atmosphere, and in the design of gas-liquid contractors for the chemical industry, as well as in determining interactions between phases in nuclear transients that are accompanied by system voiding e.g. LOCAs. Here, the Direct Numerical Simulation (DNS) of the interaction of two turbulent fluids through a flat interface has been simulated. The flow and the temperature fields are computed using a pseudospectral method. This study shows that shear stress at the interface correlates well with the heat flux. Extensive analysis of the near interface turbulence structure has been performed using quadrant analysis. From this it is clear that gas-side sweeps dominate over the high shear stress regions. This suggests that simple parameterizations based on sweep frequency may be adequate for predictions of scalar transport rates

  10. Experimental investigation on flow patterns of gas-liquid two-phase upward flow through packed channel with spheres

    International Nuclear Information System (INIS)

    Zhang Nan; Sun Zhongning; Zhao Zhongnan

    2011-01-01

    Experiments of visualized two-phase upward flow were conducted in the packed channel, which filled with 3, 5, 8 mm in diameter of glass sphere respectively. The gas superficial velocity ranges from 0.005 to 1.172 m/s. The liquid superficial velocity ranges from 0.004 to 0.093 m/s. Four representative flow patterns were observed as bubbly flow, cluster flow, liquid-pulse flow and churn-pulse flow, and corresponding flow pattern maps were also presented. It is found that the pulse flow region is dominant. The comparisons of flow pattern map between packed channel and non-packed channel show that the bubbly flow region in packed channel is narrower than that of non-packed channel due to the packing. The comparisons of flow pattern maps for three different packing sizes show that the cluster flow region expands with the increase of the packing diameter. In the low liquid superficial velocity, the cluster flow directly changes to churn-pulse flow in the packed channel with 8 mm packing. (authors)

  11. Numerical simulation of interface movement in gas-liquid two-phase flows with Level Set method

    International Nuclear Information System (INIS)

    Li Huixiong; Chinese Academy of Sciences, Beijing; Deng Sheng; Chen Tingkuan; Zhao Jianfu; Wang Fei

    2005-01-01

    Numerical simulation of gas-liquid two-phase flow and heat transfer has been an attractive work for a quite long time, but still remains as a knotty difficulty due to the inherent complexities of the gas-liquid two-phase flow resulted from the existence of moving interfaces with topology changes. This paper reports the effort and the latest advances that have been made by the authors, with special emphasis on the methods for computing solutions to the advection equation of the Level set function, which is utilized to capture the moving interfaces in gas-liquid two-phase flows. Three different schemes, i.e. the simple finite difference scheme, the Superbee-TVD scheme and the 5-order WENO scheme in combination with the Runge-Kutta method are respectively applied to solve the advection equation of the Level Set. A numerical procedure based on the well-verified SIMPLER method is employed to numerically calculate the momentum equations of the two-phase flow. The above-mentioned three schemes are employed to simulate the movement of four typical interfaces under 5 typical flowing conditions. Analysis of the numerical results shows that the 5-order WENO scheme and the Superbee-TVD scheme are much better than the simple finite difference scheme, and the 5-order WENO scheme is the best to compute solutions to the advection equation of the Level Set. The 5-order WENO scheme will be employed as the main scheme to get solutions to the advection equations of the Level Set when gas-liquid two-phase flows are numerically studied in the future. (authors)

  12. Gas-liquid two-phase flows in double inlet cyclones for natural gas separation

    DEFF Research Database (Denmark)

    Yang, Yan; Wang, Shuli; Wen, Chuang

    2017-01-01

    The gas-liquid two-phase flow within a double inlet cyclone for natural gasseparation was numerically simulated using the discrete phase model. The numericalapproach was validated with the experimental data, and the comparison resultsagreed well with each other. The simulation results showed...... that the strong swirlingflow produced a high centrifugal force to remove the particles from the gas mixture.The larger particles moved downward on the internal surface and were removeddue to the outer vortex near the wall. Most of the tiny particles went into the innervortex zones and escaped from the up...

  13. MEMBRANOUS FLOWS IN GAS-LIQUID COLLECTORS-REGENERATORS OF SOLAR ABSORPTIVE SYSTEMS FEATURES

    Directory of Open Access Journals (Sweden)

    Doroshenko А.V.

    2009-12-01

    Full Text Available Article is devoted to the creation of new generation of solar collectors of the gas-liquid type, intended for use in alternative refrigerating and conditioning systems of drying-evaporating type with direct solar regeneration of absorbent. Special attention is given to the study of membranous flows features on inclined surfaces, including questions of such flows stability.

  14. The Development of a Gas-Liquid Two-Phase Flow Sensor Applicable to CBM Wellbore Annulus.

    Science.gov (United States)

    Wu, Chuan; Wen, Guojun; Han, Lei; Wu, Xiaoming

    2016-11-18

    The measurement of wellbore annulus gas-liquid two-phase flow in CBM (coalbed methane) wells is of great significance for reasonably developing gas drainage and extraction processes, estimating CBM output, judging the operating conditions of CBM wells and analyzing stratum conditions. Hence, a specially designed sensor is urgently needed for real-time measurement of gas-liquid two-phase flow in CBM wellbore annulus. Existing flow sensors fail to meet the requirements of the operating conditions of CBM wellbore annulus due to such factors as an inapplicable measurement principle, larger size, poor sealability, high installation accuracy, and higher requirements for fluid media. Therefore, based on the principle of a target flowmeter, this paper designs a new two-phase flow sensor that can identify and automatically calibrate different flow patterns of two-phase flows. Upon the successful development of the new flow sensor, lab and field tests were carried out, and the results show that the newly designed sensor, with a measurement accuracy of ±2.5%, can adapt to the operating conditions of CBM wells and is reliable for long-term work.

  15. Energy Demodulation Algorithm for Flow Velocity Measurement of Oil-Gas-Water Three-Phase Flow

    Directory of Open Access Journals (Sweden)

    Yingwei Li

    2014-01-01

    Full Text Available Flow velocity measurement was an important research of oil-gas-water three-phase flow parameter measurements. In order to satisfy the increasing demands for flow detection technology, the paper presented a gas-liquid phase flow velocity measurement method which was based on energy demodulation algorithm combing with time delay estimation technology. First, a gas-liquid phase separation method of oil-gas-water three-phase flow based on energy demodulation algorithm and blind signal separation technology was proposed. The separation of oil-gas-water three-phase signals which were sampled by conductance sensor performed well, so the gas-phase signal and the liquid-phase signal were obtained. Second, we used the time delay estimation technology to get the delay time of gas-phase signals and liquid-phase signals, respectively, and the gas-phase velocity and the liquid-phase velocity were derived. At last, the experiment was performed at oil-gas-water three-phase flow loop, and the results indicated that the measurement errors met the need of velocity measurement. So it provided a feasible method for gas-liquid phase velocity measurement of the oil-gas-water three-phase flow.

  16. Study of Co-Current and Counter-Current Gas-Liquid Two-Phase Flow Through Packed Bed in Microgravity

    Science.gov (United States)

    Revankar, Shripad T.

    2002-11-01

    The main goal of the project is to obtain new experimental data and development of models on the co-current and counter-current gas-liquid two-phase flow through a packed bed in microgravity and characterize the flow regime transition, pressure drop, void and interfacial area distribution, and liquid hold up. Experimental data will be obtained for earth gravity and microgravity conditions. Models will be developed for the prediction of flow regime transition, void fraction distribution and interfacial area concentration, which are key parameters to characterize the packed bed performance. Thus the specific objectives of the proposed research are to: (1) Develop experiments for the study of the gas liquid two-phase flow through the packed bed with three different flow combinations: co-current down flow, co-current upflow and counter current flow. (2) Develop pore scale and bed scale two-phase instrumentation for measurement of flow regime transition, void distribution and gas-liquid interfacial area concentration in the packed bed. (3) Obtain database on flow regime transition, pressure drop, void distribution, interfacial area concentration and liquid hold up as a function of bed characteristics such as bed particle size, porosity, and liquid properties such as viscosity and surface tension. (4) Develop mathematical model for flow regime transition, void fraction distribution and interfacial area concentration for co-current gas-liquid flow through the porous bed in gravity and micro gravity conditions.(4) Develop mathematical model for the flooding phenomena in counter-current gas-liquid flow through the porous bed in gravity and micro gravity conditions. The present proposal addresses the most important topic of HEDS-specific microgravity fluid physics research identified by NASA 's one of the strategic enterprises, OBPR Enterprise. The proposed project is well defined and makes efficient use of the ground-based parabolic flight research aircraft facility. The

  17. Experimental and CFD Simulations of Vertical Two-Phase Slug Flow for Gas-Newtonian and Non-Newtonian Liquids

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Bentzen, Thomas Ruby; Majumder, S.

    Gas-liquid two-phase flows are presented everywhere in industrial processes (i.e. gas-oil pipelines). In spite of the common occurrence of these two-phase flows, their understanding is limited compared to single-phase flows. Different studies on two-phase flow have focus on developing empirical...... in the literature but none of them is enough robust and suitable for different conditions (i.e. flow patterns, gas-liquid combinations, pipe inclination angles, etc.). This clearly represents a drawback and more research in required on this field....... correlations based on large sets of experiment data for void fraction [1,2] and pressure drop [3,4] which have proven to be accurate for the specific condition that their where developed for. Currently, dozens of void fraction and pressure drop correlations for different flow patterns are available...

  18. Hydrodynamics of gas-liquid slug flow along vertical pipes in turbulent regime-An experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Mayor, T.S.; Ferreira, V.; Pinto, A.M.F.R. [Centro de Estudos de Fenomenos de Transporte, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias 4200-465 Porto (Portugal); Campos, J.B.L.M. [Centro de Estudos de Fenomenos de Transporte, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias 4200-465 Porto (Portugal)], E-mail: jmc@fe.up.pt

    2008-08-15

    An experimental study on free-bubbling gas-liquid (air-water) vertical slug flow was developed using a non-intrusive image analysis technique. The flow pattern in the near-wake of the bubbles and in the main liquid between bubbles was turbulent. A single correlation for the bubble-to-bubble interaction is proposed, relating the trailing bubble velocity to the length of the liquid slug ahead of the bubble. The proposed correlation is shown to be independent of column diameter, column vertical coordinate, superficial liquid and gas velocities and the velocity and length of the leading bubble. Frequency distribution curves, averages, modes and standard deviations are reported, for distributions of bubble velocity, bubble length and liquid slug length, for each experimental condition studied. Good agreement was found between theoretical predictions and experimental results regarding the upward velocity of undisturbed bubbles, in a 0.032 m internal diameter column. A considerable discrepancy was found, though, for a 0.052 m internal diameter column. The acquired experimental data are crucial for the development and validation of a robust slug flow simulator.

  19. Hydrodynamics of gas-liquid slug flow along vertical pipes in turbulent regime-An experimental study

    International Nuclear Information System (INIS)

    Mayor, T.S.; Ferreira, V.; Pinto, A.M.F.R.; Campos, J.B.L.M.

    2008-01-01

    An experimental study on free-bubbling gas-liquid (air-water) vertical slug flow was developed using a non-intrusive image analysis technique. The flow pattern in the near-wake of the bubbles and in the main liquid between bubbles was turbulent. A single correlation for the bubble-to-bubble interaction is proposed, relating the trailing bubble velocity to the length of the liquid slug ahead of the bubble. The proposed correlation is shown to be independent of column diameter, column vertical coordinate, superficial liquid and gas velocities and the velocity and length of the leading bubble. Frequency distribution curves, averages, modes and standard deviations are reported, for distributions of bubble velocity, bubble length and liquid slug length, for each experimental condition studied. Good agreement was found between theoretical predictions and experimental results regarding the upward velocity of undisturbed bubbles, in a 0.032 m internal diameter column. A considerable discrepancy was found, though, for a 0.052 m internal diameter column. The acquired experimental data are crucial for the development and validation of a robust slug flow simulator

  20. Experimental study on desulfurization efficiency and gas-liquid mass transfer in a new liquid-screen desulfurization system

    International Nuclear Information System (INIS)

    Sun, Zhongwei; Wang, Shengwei; Zhou, Qulan; Hui, Shi'en

    2010-01-01

    This paper presents a new liquid-screen gas-liquid two-phase flow pattern with discarded carbide slag as the liquid sorbent of sulfur dioxide (SO 2 ) in a wet flue gas desulfurization (WFGD) system. On the basis of experimental data, the correlations of the desulfurization efficiency with flue gas flow rate, slurry flow rate, pH value of slurry and liquid-gas ratio were investigated. A non-dimensional empirical model was developed which correlates the mass transfer coefficient with the liquid Reynolds number, gas Reynolds number and liquid-gas ratio (L/G) based on the available experimental data. The kinetic reaction between the SO 2 and the carbide slag depends on the pressure distribution in this desulfurizing tower, gas liquid flow field, flue gas component, pH value of slurry and liquid-gas ratio mainly. The transient gas-liquid mass transfer involving with chemical reaction was quantified by measuring the inlet and outlet SO 2 concentrations of flue gas as well as the characteristics of the liquid-screen two-phase flow. The mass transfer model provides a necessary quantitative understanding of the hydration kinetics of sulfur dioxide in the liquid-screen flue gas desulfurization system using discarded carbide slag which is essential for the practical application. (author)

  1. Gas/liquid separator for BWR type reactor

    International Nuclear Information System (INIS)

    Soma, Naoshi; Akimoto, Seiichi; Yokoyama, Iwao.

    1993-01-01

    A two phase gas/liquid flow generated at a heating portion of a nuclear reactor is swirled by inlet vanes. The phase gas/liquid flow uprises as a vortex flow in a vortex cylinder, and a liquid phase of a high density gathers at the outer circumference of the vortex cylinder. The liquid phase gathered at the outer circumference is collected at the inlet of a discharge flow channel which protrude into the vortex cylinder and in a three-step structure, and introduced into a recycling liquid phase passing through the discharge flow channel for liquid phase. There is provided a structure that separated liquid collected at the lowermost state in the inlet of the three-step discharge flow channel inlet descends in the discharge flow channel, then uprises in an uprising flow channel and is introduced into the recycling liquid phase by way of a discharge flow channel exit. The height of the discharge flow channel exit is determined equal to that of a liquid level of the recycling liquid phase during rated operation of the reactor. Accordingly, even in a case where the liquid level in the recycling liquid phase is lowered, the liquid level of the uprising flow channel is kept equal to that during rated operation. (I.N.)

  2. Atomizing industrial gas-liquid flows – Development of an efficient hybrid VOF-LPT numerical framework

    International Nuclear Information System (INIS)

    Ström, Henrik; Sasic, Srdjan; Holm-Christensen, Olav; Shah, Louise Jivan

    2016-01-01

    Highlights: • Modelling of turbulent atomizing gas-liquid flows in real industrial devices. • A combined VOF-LPT framework with statistical coupling. • Regions of separated and dispersed multiphase flow treated simultaneously. • Statistical model based on a limited amount of highly resolved VOF data. - Abstract: Atomizing gas-liquid flows are used in industrial applications where high interphase heat and mass transfer rates and good mixing are of primary importance. Today, there is no single mathematical framework available to predict the entire liquid breakup process at an acceptable computational cost for a typical problem of industrial size. In this work, we develop a volume-of-fluid (VOF) framework that is combined with Lagrangian particle tracking (LPT) to take advantage of the respective strengths of these two approaches. The two frameworks are coupled via a statistical model that enables a transition from the VOF to the LPT formulation using input data about the primary breakup process obtained from detailed VOF simulations in dedicated switching zones. LPT-to-VOF transitions are handled directly by analyzing the proximity of LPT parcels to larger VOF structures. The combined framework is specifically designed to accommodate situations where atomization occurs in several locations simultaneously and when separated and dispersed turbulent gas-liquid flows co-exist in the same industrial unit. The procedure in which the statistical model is derived is presented and discussed, its performance is verified and the computational efficiency of the combined VOF-LPT model is assessed. Finally, the application of the coupled framework to the simulation of an industrial gas-liquid mixer with four separate atomization regions is presented.

  3. A numerical study on the influence of gas-liquid two phase flow on the rotary pump performances

    International Nuclear Information System (INIS)

    Miao, T C; Liu, Y Y; Zhao, F; Wang, L Q

    2013-01-01

    Rotary pump can be used in many fields because of its strong self-priming ability. Many factors may cause the medium in rotary pump system containing gas-liquid two phase. And the suction capacity of rotary pump will decrease sharply in these situations. To study the internal flow mechanism of rotary pump when transporting medium containing gas, the gas-liquid two phase flow in the rotary pump system has been simulated using VOF model under different gas fractions. And the interaction between rotary pump and the pipeline has been considered. The simulation results coincide well with the theoretical calculation results, and the distribution of the flow field match well with the Mandhane flow pattern map. The main conclusions are as follows: with the increase of gas fraction, the flow pattern in the pipeline has the following evolutionary trend (bubble – plug – slug – wavy), and the suction capacity of the pump will decrease. It is mainly because gas medium can fill the partial vacuum produced by the rotor motion easily and is easier to have backflow

  4. Experimental investigation of the liquid volumetric mass transfer coefficient for upward gas-liquid two-phase flow in rectangular microchannels

    Directory of Open Access Journals (Sweden)

    X. Y. Ji

    2010-12-01

    Full Text Available The gas-liquid two-phase mass transfer process in microchannels is complicated due to the special dynamical characteristics. In this work, a novel method was explored to measure the liquid side volumetric mass transfer coefficient kLa. Pressure transducers were utilized to measure the pressure variation of upward gas-liquid two-phase flow in three vertical rectangular microchannels and the liquid side volumetric mass transfer coefficient kLa was calculated through the Pressure-Volume-Temperature correlation of the gas phase. Carbon dioxide-water, carbon dioxide-ethanol and carbon dioxide-n-propanol were used as working fluids, respectively. The dimensions of the microchannels were 40 µm×240 µm (depth×width, 100 µm×800 µm and 100 µm×2000 µm, respectively. Results showed that the channel diameter and the capillary number influence kLa remarkably and that the maximum value of kLa occurs in the annular flow regime. A new correlation of kLa was proposed based on the Sherwood number, Schmidt number and the capillary number. The predicted values of kLa agreed well with the experimental data.

  5. Turbulent mixing between subchannels in a gas-liquid two-phase flow. For the equilibrium flow without net fluid transfer between subchannels

    International Nuclear Information System (INIS)

    Kawahara, Akimaro; Sadatomi, Michio; Sato, Yoshifusa; Saito, Hidetoshi.

    1995-01-01

    To provide data necessary for modeling turbulent mixing between subchannels in a nuclear fuel rod bundle, three experiments were made in series for equilibrium two-phase flows, in which net mass exchange does not occur between subchannels for each phase. The first one was the measurement of turbulent mixing rates of both gas and liquid phases by a tracer technique, using air and water as the working fluids. Three kinds of vertical test channels consisting of two subchannels were used. The data have shown that the turbulent mixing rate of each phase in a two-phase flow is strongly dependent on flow regime. So, to see the relation between turbulent mixing and two-phase flow configuration in the subchannels, the second experiment, flow visualization, was made. It was observed in slug and churn flows that a lateral inter-subchannel liquid flow of a large scale is caused by the successive axial transit of large gas bubbles in each subchannel, and the turbulent mixing for the liquid phase is dominated by this lateral flow. To investigate a driving force of such large scale lateral flow, the third experiment, the measurement of an instantaneous pressure differential between the subchannels, was made. The result showed that there is a close relationship between the liquid phase mixing rate and the magnitude of the pressure differential fluctuation. (author)

  6. Hydrodynamic flow regimes, gas holdup, and liquid circulation in airlift reactors

    Energy Technology Data Exchange (ETDEWEB)

    Abashar, M.E.; Narsingh, U.; Rouillard, A.E.; Judd, R. [Univ. of Durban (South Africa)

    1998-04-01

    This study reports an experimental investigation into the hydrodynamic behavior of an external-loop airlift reactor (ALR) for the air-water system. Three distinct flow regimes are identified--namely homogeneous, transition, and heterogeneous regimes. The transition between homogeneous and heterogeneous flow is observed to occur over a wide range rather than being merely a single point as has been previously reported in the literature. A gas holdup correlation is developed for each flow regime. The correlations fit the experimental gas holdup data with very good accuracy (within {+-}5%). It would appear, therefore, that a deterministic equation to describe each flow regime is likely to exist in ALRs. This equation is a function of the reactor geometry and the system`s physical properties. New data concerning the axial variation of gas holdup is reported in which a minimum value is observed. This phenomenon is discussed and an explanation offered. Discrimination between two sound theoretical models--namely model 1 (Chisti et al., 1988) and model 2 (Garcia Calvo, 1989)--shows that model 1 predicts satisfactorily the liquid circulation velocity with an error of less than {+-} 10%. The good predictive features of model 1 may be due to the fact that it allows for a significant energy dissipation by wakes behind bubbles. Model 1 is now further improved by the new gas holdup correlations which are derived for the three different flow regimes.

  7. Convection flow study within a horizontal fluid layer under the action of gas flow

    Directory of Open Access Journals (Sweden)

    Kreta Aleksei

    2016-01-01

    Full Text Available Experimental investigation of convective processes within horizontal evaporating liquid layer under shear–stress of gas flow is presented. It is found the structures of the convection, which move in opposite direction relative to each other. First convective structure moves in reverse direction with the flow of gas, and the second convective structure moves towards the gas flow. Convection flow within the liquid layer is registered with help of PIV technique. Average evaporation flow rate of Ethanol liquid layer under Air gas flow is measured. Influence of the gas velocity, at a constant temperature of 20 °C, on the evaporation flow rate has been studied.

  8. Cellular properties of slug flow in vertical co-current gas-liquid flow: slug-churn transition

    International Nuclear Information System (INIS)

    Lusseyran, Francois

    1990-01-01

    This research thesis reports the study and description of the structure of a slug flow regime in a co-current vertical cylindrical duct, and the characterization and prediction of its transition towards a slug-churn (de-structured) regime. Flow physical mechanisms highlighted by the measurement of two important dynamics variables (wall friction and thickness of liquid films) are related to hypotheses of cellular models. The author first proposes an overview of slug flow regimes: theoretical steady and one-dimensional analysis, mass assessment equations of cellular models, application to the assessment of the flow rate and of the thickness of the film surrounding the gas slug. In the second part, the author addresses the slug flow regime transition towards the slug-churn regime: assessment of the evolution of flow dynamic properties, use of average wall friction analysis to obtain a relevant transition criterion. The third part presents experimental conditions, and measurement methods: conductometry for thickness measurement, polarography for wall friction measurement, and gas phase detection by using an optic barrier or optic fibres [fr

  9. Dynamic simulation of dispersed gas-liquid two-phase flow using a discrete bubble model.

    NARCIS (Netherlands)

    Delnoij, E.; Lammers, F.A.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

    1997-01-01

    In this paper a detailed hydrodynamic model for gas-liquid two-phase flow will be presented. The model is based on a mixed Eulerian-Lagrangian approach and describes the time-dependent two-dimensional motion of small, spherical gas bubbles in a bubble column operating in the homogeneous regime. The

  10. A study on the effect of gas flow rate on the wave characteristics in two-phase gas-liquid annular flow

    Energy Technology Data Exchange (ETDEWEB)

    Han Huawei [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa, Ont., L1H 7K4 (Canada)]. E-mail: colin.han@uoit.ca; Zhu Zhenfeng [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, Sask., S7N 5A9 (Canada)]. E-mail: zhz752@mail.usask.ca; Gabriel, Kamiel [University of Ontario Institute of Technology, Oshawa, Ont., L1H 7K4 (Canada)]. E-mail: kamiel.gabriel@uoit.ca

    2006-12-15

    Interfacial waves play a very important role in the mass, momentum and energy transport phenomena in annular flow. In this paper, film thickness time-trace measurements for air-water annular flow were collected in a small vertical tube using a parallel wire probe. Using the data, a typical disturbance wave shape was obtained and wave properties (e.g., width, height, speed and roughness) were presented. The liquid mass flux ranged from 100 to 200 kg/m{sup 2} s and the gas mass flux ranged from 18 to 47 kg/m{sup 2} s. Disturbance wave characteristics were defined and the effects of changing the gas flow rate on the wave spacing, wave width, wave peak height and wave base height were studied. An average velocity model for the wave and base regions has been developed to determine the wave velocity. The investigation method could be further extended to annular-mist flow which frequently occurs in boiling water reactors.

  11. A study on the effect of gas flow rate on the wave characteristics in two-phase gas-liquid annular flow

    International Nuclear Information System (INIS)

    Han Huawei; Zhu Zhenfeng; Gabriel, Kamiel

    2006-01-01

    Interfacial waves play a very important role in the mass, momentum and energy transport phenomena in annular flow. In this paper, film thickness time-trace measurements for air-water annular flow were collected in a small vertical tube using a parallel wire probe. Using the data, a typical disturbance wave shape was obtained and wave properties (e.g., width, height, speed and roughness) were presented. The liquid mass flux ranged from 100 to 200 kg/m 2 s and the gas mass flux ranged from 18 to 47 kg/m 2 s. Disturbance wave characteristics were defined and the effects of changing the gas flow rate on the wave spacing, wave width, wave peak height and wave base height were studied. An average velocity model for the wave and base regions has been developed to determine the wave velocity. The investigation method could be further extended to annular-mist flow which frequently occurs in boiling water reactors

  12. Numerical simulation of gas-liquid two-phase flow and convective heat transfer in a micro tube

    International Nuclear Information System (INIS)

    Fukagata, Koji; Kasagi, Nobuhide; Ua-arayaporn, Poychat; Himeno, Takehiro

    2007-01-01

    Numerical simulation of an air and water two-phase flow in a 20 μm ID tube is carried out. A focus is laid upon the flow and heat transfer characteristics in bubble-train flows. An axisymmetric two-dimensional flow is assumed. The finite difference method is used to solve the governing equations, while the level set method is adopted for capturing the interface of gas and liquid. In each simulation, the mean pressure gradient and the wall heat flux are kept constant. The simulation is repeated under different conditions of pressure gradient and void fraction. The superficial Reynolds numbers of gas and liquid phases studied are 0.34-13 and 16-490, respectively, and the capillary number is 0.0087-0.27. Regardless of the flow conditions, the gas-phase velocity is found approximately 1.2 times higher than the liquid-phase velocity. This is in accordance with the Armand correlation valid for two-phase flows in macro-sized tubes. The two-phase friction coefficient is found to be scaled with the Reynolds number based on the effective viscosity of the Einstein type. The computed wall temperature distribution is qualitatively similar to that observed experimentally in a mini channel. The local Nusselt number beneath the bubble is found notably higher than that of single-phase flow

  13. An investigation on near wall transport characteristics in an adiabatic upward gas-liquid two-phase slug flow

    Science.gov (United States)

    Zheng, Donghong; Che, Defu

    2007-08-01

    The near-wall transport characteristics, inclusive of mass transfer coefficient and wall shear stress, which have a great effect on gas-liquid two-phase flow induced internal corrosion of low alloy pipelines in vertical upward oil and gas mixing transport, have been both mechanistically and experimentally investigated in this paper. Based on the analyses on the hydrodynamic characteristics of an upward slug unit, the mass transfer in the near wall can be divided into four zones, Taylor bubble nose zone, falling liquid film zone, Taylor bubble wake zone and the remaining liquid slug zone; the wall shear stress can be divided into two zones, the positive wall shear stress zone associated with the falling liquid film and the negative wall shear stress zone associated with the liquid slug. Based on the conventional mass transfer and wall shear stress characteristics formulas of single phase liquid full-pipe turbulent flow, corrected normalized mass transfer coefficient formula and wall shear stress formula are proposed. The calculated results are in good agreement with the experimental data. The shear stress and the mass transfer coefficient in the near wall zone are increased with the increase of superficial gas velocity and decreased with the increase of superficial liquid velocity. The mass transfer coefficients in the falling liquid film zone and the wake zone of leading Taylor bubble are lager than those in the Taylor bubble nose zone and the remaining liquid slug zone, and the wall shear stress associated falling liquid film is larger than that associated the liquid slug. The mass transfer coefficient is within 10-3 m/s, and the wall shear stress below 103 Pa. It can be concluded that the alternate wall shear stress due to upward gas-liquid slug flow is considered to be the major cause of the corrosion production film fatigue cracking.

  14. Transport evaluation of a gas-liquid scrubber

    International Nuclear Information System (INIS)

    Brodner, A.J.; Bistline, J.E.; Weber, S.E.

    1982-10-01

    The hydraulics and the mass-transfer behavior of a five-tray, single-bubble-cap, single-downcomer, gas-liquid contactor were studied for use as a gas scrubber. Flooding was not observed at the maximum available liquid and gas flow rates of 0.32 and 464 L/min, respectively. The maximum liquid entrainment was 33% at a gross liquid flow rate of 0.05 L/min. The Murphree-tray efficiencies for absorption of CO 2 (5000 ppM in air) into demineralized water ranged from 0.14 to 0.74 for volumetric liquid-to-gas ratios of 4 x 10 -4 and 2 x 10 -4 , respectively, for k/sub L/a values ranging from 0.088 to 0.36 min -1 . 12 figures, 10 tables

  15. Transition of Gas-Liquid Stratified Flow in Oil Transport Pipes

    Directory of Open Access Journals (Sweden)

    D. Lakehal

    2011-12-01

    Full Text Available Large-Scale Simulation results of the transition of a gas-liquid stratified flow to slug flow regime in circular 3D oil transport pipes under turbulent flow conditions expressed. Free surface flow in the pipe is treated using the Level Set method. Turbulence is approached via the LES and VLES methodologies extended to interfacial two-phase flows. It is shown that only with the Level Set method the flow transition can be accurately predicted, better than with the two-fluid phase-average model. The transition from stratified to slug flow is found to be subsequent to the merging of the secondary wave modes created by the action of gas shear (short waves with the first wave mode (high amplitude long wave. The model is capable of predicting global flow features like the onset of slugging and slug speed. In the second test case, the model predicts different kinds of slugs, the so-called operating slugs formed upstream that fill entirely the pipe with water slugs of length scales of the order of 2-4 D, and lower size (1-1.5 D disturbance slugs, featuring lower hold-up (0.8-0.9. The model predicts well the frequency of slugs. The simulations revealed important parameter effects on the results, such as two-dimensionality, pipe length, and water holdup.

  16. Numerical Study of Particle Interaction in Gas-Particle and Liquid-Particle Flows: Part I Analysis and Validation

    Directory of Open Access Journals (Sweden)

    K. Mohanarangam

    2009-09-01

    Full Text Available A detailed study into the turbulent behaviour of dilute particulate flow under the influence of two carrier phases namely gas and liquid has been carried out behind a sudden expansion geometry. The major endeavour of the study is to ascertain the response of the particles within the carrier (gas or liquid phase. The main aim prompting the current study is the density difference between the carrier and the dispersed phases. While the ratio is quite high in terms of the dispersed phase for the gas-particle flows, the ratio is far more less in terms of the liquid-particle flows. Numerical simulations were carried out for both these classes of flows using an Eulerian two-fluid model with RNG based k-emodel as the turbulent closure. An additional kinetic energy equation to better represent the combined fluid-particle behaviour is also employed in the current set of simulations. In the first part of this two part series, experimental results of Fessler and Eaton (1995 for Gas-Particle (GP flow and that of Founti and Klipfel (1998 for Liquid-Particle (LP flow have been compared and analysed. This forms the basis of the current study which aims to look at the particulate behaviour under the influence of two carrier phases. Further numerical simulations were carried out to test whether the current numerical formulation can used to simulate these varied type of flows and the same were validated against the experimental data of both GP as well LP flow. Qualitative results have been obtained for both these classes of flows with their respective experimental data both at the mean as well as at the turbulence level for carrier as well as the dispersed phases.

  17. Liquid dispersion in trickle-bed reactors with gas-liquid cocurrent downflow

    International Nuclear Information System (INIS)

    Chu, C.F.; Ng, K.M.

    1986-01-01

    The flow pattern can deviate from ideal plug flow in both trickling and pulsing flows. The liquid dispersion in those flow regimes are investigated separately, as the mechanisms causing the deviation of flow pattern from plug flow are different. In trickling flow, the dispersion of the liquid phase occurs in the flow path which is determined with computer-generated packed column. Dispersion in pulsing flow is studied with a combination of the method of characteristics and analysis of liquid dispersion in the liquid slug and gas pulse. The axial dispersion coefficients are then determined based on Monte Carlo simulation. Finally, liquid dispersion in trickle beds containing porous packings is also discussed

  18. Void fraction and interfacial velocity in gas-liquid upward two-phase flow across tube bundles

    International Nuclear Information System (INIS)

    Ueno, T.; Tomomatsu, K.; Takamatsu, H.; Nishikawa, H.

    1997-01-01

    Tube failures due to flow-induced vibration are a major problem in heat exchangers and many studies on the problem of such vibration have been carried out so far. Most studies however, have not focused on two-phase flow behavior in tube bundles, but have concentrated mainly on tube vibration behavior like fluid damping, fluid elastic instability and so on. Such studies are not satisfactory for understanding the design of heat exchangers. Tube vibration behavior is very complicated, especially in the case of gas-liquid two-phase flow, so it is necessary to investigate two-phase flow behavior as well as vibration behavior before designing heat exchangers. This paper outlines the main parameters that characterize two-phase behavior, such as void fraction and interfacial velocity. The two-phase flow analyzed here is gas-liquid upward flow across a horizontal tube bundle. The fluids tested were HCFC-123 and steam-water. HCFC-123 stands for Hydrochlorofluorocarbon. Its chemical formula is CHCl 2 CF 3 , which has liquid and gas densities of 1335 and 23.9 kg/m 3 at a pressure of 0.40 MPa and 1252 and 45.7 kg/m 3 at a pressure of 0.76 MPa. The same model tube bundle was used in the two tests covered in this paper, to examine the similarity law of two-phase flow behavior in tube bundles using HCFC-123 and steam-water two-phase flow. We also show numerical simulation results for the two fluid models in this paper. We do not deal with vibration behavior and the relationship between vibration behavior and two-phase flow behavior. (author)

  19. Visualization and measurement of gas-liquid metal two-phase flow with large density difference using thermal neutrons as microscopic probes

    International Nuclear Information System (INIS)

    Saito, Y.; Hibiki, T.; Mishima, K.; Nishihara, H.; Yamamoto, A.; Kanda, K.; Tobita, Y.; Konishi, K.; Matsubayashi, M.

    1998-01-01

    In a core melt accident of a fast breeder reactor there is a possibility of boiling of fuel-steel mixture in the containment pool. In relation to safety evaluation on severe accident, it is indispensable to evaluate the recriticality of melted core. Gas-liquid two-phase flow with a large density difference is formed due to the boiling of fuel-steel mixture. Although the large density difference may affect the basic characteristics of two-phase flow, little work has been performed so far on two-phase flow with large density difference has not been performed well. In this study, visualization and void fraction measurement of gas-liquid metal two-phase flow were performed by using neutron radiography. The effect of the large density difference between gas and liquid phases on the basic flow characteristics of two-phase flow was clarified. (author)

  20. Temporal and spatial evolution characteristics of gas-liquid two-phase flow pattern based on image texture spectrum descriptor

    Science.gov (United States)

    Zhou, Xi-Guo; Jin, Ning-De; Wang, Zhen-Ya; Zhang, Wen-Yin

    2009-11-01

    The dynamic image information of typical gas-liquid two-phase flow patterns in vertical upward pipe is captured by a highspeed dynamic camera. The texture spectrum descriptor is used to describe the texture characteristics of the processed images whose content is represented in the form of texture spectrum histogram, and four time-varying characteristic parameter indexes which represent image texture structure of different flow patterns are extracted. The study results show that the amplitude fluctuation of texture characteristic parameter indexes of bubble flow is lowest and shows very random complex dynamic behavior; the amplitude fluctuation of slug flow is higher and shows intermittent motion behavior between gas slug and liquid slug, and the amplitude fluctuation of churn flow is the highest and shows better periodicity; the amplitude fluctuation of bubble-slug flow is from low to high and oscillating frequence is higher than that of slug flow, and includes the features of both slug flow and bubble flow; the slug-churn flow loses the periodicity of slug flow and churn flow, and the amplitude fluctuation is high. The results indicate that the image texture characteristic parameter indexes of different flow pattern can reflect the flow characteristics of gas-liquid two-phase flow, which provides a new approach to understand the temporal and spatial evolution of flow pattern dynamics.

  1. Real-time measurement of gas and liquid flow rates in two-phase slug flow by an advanced electromagnetic flowmeter and conductance probes

    International Nuclear Information System (INIS)

    Kim Jongrok; Ahn Yeh-Chan; Oh Byung Do; Kang Deok-Hong; Kim Moo Hwan

    2005-01-01

    Full text of publication follows: In order to measure the liquid mean velocity (cross-sectional average) in two-phase flow with an electromagnetic flowmeter, each flow pattern must be considered separately because of their different flow characteristics. Since bubbly flow can be approximated as a homogeneous mixture of gas and liquid at the same velocity, there are no additional measurement difficulties compared to single-phase flow. Cha et al. (2002) and Knoll (1991) reported that this approximation gives rise to no more than a 5% error in the liquid flow rate when the void fraction is less than 0.25. Annular flow measurements are also similar to those of single-phase flow if the film is assumed to be uniform and smooth, and the gas core is located at the center of the flow tube. Slug flow, however, is the most complicated, since the liquid axial velocity over a slug unit experiences considerable acceleration or deceleration. Therefore an electromagnetic flowmeter with high temporal resolution is needed. In slug flow, film velocity measurements are also difficult to perform because the liquid film is very thin and can be easily disturbed, thus altering the flow field. Only two experimental results for liquid film velocity measurement could be found. They were performed using photo-chromic dye method (DeJesus, 1997) and PIV technique (Polonsky et al., 1999). In this study, an advanced electromagnetic flow-metry was developed to measure liquid mean velocity with high transients. In addition, two ring-type conductance meters were manufactured to measure void fraction and its propagation speed in slug flow. The signal of conductance meter with two rings depends on liquid temperature. Therefore a conductance meter with three rings designed by Coney (1973), which is independent of liquid temperature, was used and experimentally proved. The manufactured conductance meters showed a good repeatability and agreement with the analytical solution by Coney (1973). From the

  2. Churn-annular flow pattern transition in a vertical upward gas-liquid two-phase flow in various conduits

    International Nuclear Information System (INIS)

    Takenaka, Nobuyuki; Ueda, Tadanobu; Asano, Hitoshi

    2008-01-01

    Void fraction was measured by neutron radiography for a vertical upward gas-water two-phase flow in a concentric annular tube with and with out a spacer, 4x4 rod bundle with and without a spacer and a tight rod bundle with and without a wrapping wire for various gas and liquid flow rates. The flow patterns of these two-phase flows were determined by the Mishima-Ishii flow pattern map and void fraction was calculated by the Ishii's drift flux model. The predicted values were compared with the experimental results. The void fraction was well predicted by the Mishima-Ishii flow pattern map and the Ishii's drift flux model except the annular flow region with void fraction lower than 0.8 for conduits with small equivalent diameter. A new churn-annular flow pattern transition condition of the void fraction equal to 0.8 was added. The void fraction for the present experimental condition was successful predicted with the new transition model. (author)

  3. The Effect of Surfactants on Gas-Liquid Pipe Flows

    NARCIS (Netherlands)

    Van Nimwegen, A.T.

    2015-01-01

    Liquid loading is a major problem in the natural gas industry, in which gas production is limited by the accumulation of liquids in the well tubing. Liquid loading can be prevented by the injection of surfactants at the bottom of the well. The surfactants cause the liquid in the well to foam,

  4. Linear and nonlinear instability in vertical counter-current laminar gas-liquid flows

    Science.gov (United States)

    Schmidt, Patrick; Ó Náraigh, Lennon; Lucquiaud, Mathieu; Valluri, Prashant

    2016-04-01

    We consider the genesis and dynamics of interfacial instability in vertical gas-liquid flows, using as a model the two-dimensional channel flow of a thin falling film sheared by counter-current gas. The methodology is linear stability theory (Orr-Sommerfeld analysis) together with direct numerical simulation of the two-phase flow in the case of nonlinear disturbances. We investigate the influence of two main flow parameters on the interfacial dynamics, namely the film thickness and pressure drop applied to drive the gas stream. To make contact with existing studies in the literature, the effect of various density contrasts is also examined. Energy budget analyses based on the Orr-Sommerfeld theory reveal various coexisting unstable modes (interfacial, shear, internal) in the case of high density contrasts, which results in mode coalescence and mode competition, but only one dynamically relevant unstable interfacial mode for low density contrast. A study of absolute and convective instability for low density contrast shows that the system is absolutely unstable for all but two narrow regions of the investigated parameter space. Direct numerical simulations of the same system (low density contrast) show that linear theory holds up remarkably well upon the onset of large-amplitude waves as well as the existence of weakly nonlinear waves. For high density contrasts, corresponding more closely to an air-water-type system, linear stability theory is also successful at determining the most-dominant features in the interfacial wave dynamics at early-to-intermediate times. Nevertheless, the short waves selected by the linear theory undergo secondary instability and the wave train is no longer regular but rather exhibits chaotic motion. The same linear stability theory predicts when the direction of travel of the waves changes — from downwards to upwards. We outline the practical implications of this change in terms of loading and flooding. The change in direction of the

  5. Linear and nonlinear instability in vertical counter-current laminar gas-liquid flows

    International Nuclear Information System (INIS)

    Schmidt, Patrick; Lucquiaud, Mathieu; Valluri, Prashant; Ó Náraigh, Lennon

    2016-01-01

    We consider the genesis and dynamics of interfacial instability in vertical gas-liquid flows, using as a model the two-dimensional channel flow of a thin falling film sheared by counter-current gas. The methodology is linear stability theory (Orr-Sommerfeld analysis) together with direct numerical simulation of the two-phase flow in the case of nonlinear disturbances. We investigate the influence of two main flow parameters on the interfacial dynamics, namely the film thickness and pressure drop applied to drive the gas stream. To make contact with existing studies in the literature, the effect of various density contrasts is also examined. Energy budget analyses based on the Orr-Sommerfeld theory reveal various coexisting unstable modes (interfacial, shear, internal) in the case of high density contrasts, which results in mode coalescence and mode competition, but only one dynamically relevant unstable interfacial mode for low density contrast. A study of absolute and convective instability for low density contrast shows that the system is absolutely unstable for all but two narrow regions of the investigated parameter space. Direct numerical simulations of the same system (low density contrast) show that linear theory holds up remarkably well upon the onset of large-amplitude waves as well as the existence of weakly nonlinear waves. For high density contrasts, corresponding more closely to an air-water-type system, linear stability theory is also successful at determining the most-dominant features in the interfacial wave dynamics at early-to-intermediate times. Nevertheless, the short waves selected by the linear theory undergo secondary instability and the wave train is no longer regular but rather exhibits chaotic motion. The same linear stability theory predicts when the direction of travel of the waves changes — from downwards to upwards. We outline the practical implications of this change in terms of loading and flooding. The change in direction of the

  6. Visualization of two-phase gas-liquid flow regimes in horizontal and slightly-inclined circular tubes

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Livia Alves [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Nuclear Engineering Institute (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)], E-mail: livia@lasme.coppe.ufrj.br; Cunha Filho, Jurandyr; Su, Jian [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Nuclear Engineering Program], Emails: cunhafilho@lasme.coppe.ufrj.br, sujian@lasme.coppe.ufrj.br; Faccini, Jose Luiz Horacio [Nuclear Engineering Institute (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)], E-mail: faccini@ien.gov.br

    2010-07-01

    In this paper a flow visualization study was performed for two-phase gas-liquid flow in horizontal and slightly inclined tubes. The test section consists of a 2.54 cm inner diameter stainless steel circular tube, followed by a transparent acrylic tube with the same inner diameter. The working fluids were air and water, with liquid superficial velocities ranging from 0:11 to 3:28 m/s and gas superficial velocities ranging from 0:27 to 5:48 m/s. Flow visualization was executed for upward flow at 5 deg and 10 deg and downward flow at 2:5 deg, 5 deg and 10 deg, as well as for horizontal flow. The visualization technique consists of a high-speed digital camera that records images at rates of 125 and 250 frames per second of a concurrent air-water mixture through a transparent part of the tube. From the obtained images, the flow regimes were identified (except for annular flow), observing the effect of inclination angles on flow regime transition boundaries. Finally, the experimental results were compared with empirical and theoretical flow pattern maps available in literature. (author)

  7. Effect of drag-reducing polymers on Tubing Performance Curve (TPC) in vertical gas-liquid flows

    NARCIS (Netherlands)

    Shoeibi Omrani, P.; Veltin, J.; Turkenburg, D.H.

    2014-01-01

    This paper discusses the effect of drag reducing polymers on the Tubing Performance Curve (TPC) of vertical air-water flows at near atmospheric conditions. The effect of polymer concentration, liquid and gas flow rates on the pressure drop curve (Tubing Performance Curve) was investigated

  8. Gas-Liquid Two-Phase Flows Through Packed Bed Reactors in Microgravity

    Science.gov (United States)

    Motil, Brian J.; Balakotaiah, Vemuri

    2001-01-01

    The simultaneous flow of gas and liquid through a fixed bed of particles occurs in many unit operations of interest to the designers of space-based as well as terrestrial equipment. Examples include separation columns, gas-liquid reactors, humidification, drying, extraction, and leaching. These operations are critical to a wide variety of industries such as petroleum, pharmaceutical, mining, biological, and chemical. NASA recognizes that similar operations will need to be performed in space and on planetary bodies such as Mars if we are to achieve our goals of human exploration and the development of space. The goal of this research is to understand how to apply our current understanding of two-phase fluid flow through fixed-bed reactors to zero- or partial-gravity environments. Previous experiments by NASA have shown that reactors designed to work on Earth do not necessarily function in a similar manner in space. Two experiments, the Water Processor Assembly and the Volatile Removal Assembly have encountered difficulties in predicting and controlling the distribution of the phases (a crucial element in the operation of this type of reactor) as well as the overall pressure drop.

  9. A Radiative Transfer Modeling Methodology in Gas-Liquid Multiphase Flow Simulations

    Directory of Open Access Journals (Sweden)

    Gautham Krishnamoorthy

    2014-01-01

    Full Text Available A methodology for performing radiative transfer calculations in computational fluid dynamic simulations of gas-liquid multiphase flows is presented. By considering an externally irradiated bubble column photoreactor as our model system, the bubble scattering coefficients were determined through add-on functions by employing as inputs the bubble volume fractions, number densities, and the fractional contribution of each bubble size to the bubble volume from four different multiphase modeling options. The scattering coefficient profiles resulting from the models were significantly different from one another and aligned closely with their predicted gas-phase volume fraction distributions. The impacts of the multiphase modeling option, initial bubble diameter, and gas flow rates on the radiation distribution patterns within the reactor were also examined. An increase in air inlet velocities resulted in an increase in the fraction of larger sized bubbles and their contribution to the scattering coefficient. However, the initial bubble sizes were found to have the strongest impact on the radiation field.

  10. Two-component HLMC-gas flow instability and inhomogeneity phenomena in open-pool reactor

    International Nuclear Information System (INIS)

    Sergey I Shcherbakov

    2005-01-01

    Full text of publication follows: Consideration is being given to two-component gas-liquid flows with inhomogeneous gas content. The inhomogeneity of gas content over flow space can be caused by local mixing of gas and liquid, gas injection, gas-containing liquid jet penetration into the bulk of liquid without gas. The paper presents the computational results obtained using the direct non-stationary calculation with the TURBO-FLOW computer code. The results refer to flows near the liquid level, flows in downcomer gaps, collectors, elements with varying geometry (jet outlet into space, flow turn) for the pool-type reactors and experimental models. The following processes have been shown and discussed: formation of new liquid levels, entrainment of gas from the level, change in density composition of gas, flow stratification, effect of gas emergence rate and density convection on flow pattern. At gas phase transfer by liquid, two phenomena governing this transfer proceed: gas slip in liquid and density convection of non-uniformly aerated liquid. In horizontal flows, a vertical stratification of gas content always occurs. If the flow changes its direction to an upward one (collector at core inlet), the gas content maximum would be observed in channels nearest to the inlet. At the liquid level, the processes of gas separation from liquid and gas entrainment take place. The separation is a self-sustained process due to circulations arising near the level. The rate of gas entrainment is proportional to the rate of overflow and inversely proportional to the height of liquid level. At the downcomer region in case of its expansion, there occurs the instability of flow resulting in formation of liquid level and falling jet. The level is lower the more the gas content at inlet. The accumulation of gas occurs at sharp turns, encumbered regions (tube bundle), at all regions with upper (ceiling) constraints of flow. The flow instability being often observed in gas-liquid flows

  11. Hydrodynamic boundary conditions for one-component liquid-gas flows on non-isothermal solid substrates

    KAUST Repository

    Xu, Xinpeng

    2012-01-01

    Recently, liquid-gas flows related to droplets, bubbles, and thin films on solid surfaces with thermal and wettability gradients have attracted widespread attention because of the many physical processes involved and their promising potential applications in biology, chemistry, and industry. Various new physical effects have been discovered at fluid-solid interfaces by experiments and molecular dynamics simulations, e.g., fluid velocity slip, temperature slip (Kapitza resistance), mechanical-thermal cross coupling, etc. There have been various models and theories proposed to explain these experimental and numerical observations. However, to the best of our knowledge,a continuum hydrodynamic model capable of predicting the temperature and velocity profiles of liquid-gas flows on non-isothermal, heterogeneous solid substrates is still absent. The purpose of this work is to construct a continuum model for simulating the liquid-gas flows on solid surfaces that are flat and rigid, and may involve wettability gradients and thermal gradients. This model is able to describe fluid velocity slip, temperature slip, and mechanical-thermal coupling that may occur at fluid-solid interfaces. For this purpose, we first employ the diffuse interface modeling to formulate the hydrodynamic equations for one-component liquid-gas flows in the bulk region. This reproduces the dynamic van der Waals theory of Onuki [Phys. Rev. Lett., 94: 054501, 2005]. We then extendWaldmann\\'s method [Z. Naturforsch. A, 22: 1269-1280, 1967] to formulate the boundary conditions at the fluid-solid interface that match the hydrodynamic equations in the bulk. The effects of the solid surface curvature are also briefly discussed in the appendix. The guiding principles of our model derivation are the conservation laws and the positive definiteness of entropy production together with the Onsager reciprocal relation. The derived model is self-consistent in the sense that the boundary conditions are

  12. Pore-scale analysis of the minimum liquid film thickness around elongated bubbles in confined gas-liquid flows

    Science.gov (United States)

    Magnini, M.; Beisel, A. M.; Ferrari, A.; Thome, J. R.

    2017-11-01

    The fluid mechanics of elongated bubbles in confined gas-liquid flows in micro-geometries is important in pore-scale flow processes for enhanced oil recovery and mobilization of colloids in unsaturated soil. The efficiency of such processes is traditionally related to the thickness of the liquid film trapped between the elongated bubble and the pore's wall, which is assumed constant. However, the surface of long bubbles presents undulations in the vicinity of the rear meniscus, which may significantly decrease the local thickness of the liquid film, thus impacting the process of interest. This study presents a systematic analysis of these undulations and the minimum film thickness induced in the range Ca = 0.001- 0.5 and Re = 0.1- 2000 . Pore-scale Computational Fluid Dynamics (CFD) simulations are performed with a self-improved version of the opensource solver ESI OpenFOAM which is based on a Volume of Fluid method to track the gas-liquid interface. A lubrication model based on the extension of the classical axisymmetric Bretherton theory is utilized to better understand the CFD results. The profiles of the rear meniscus of the bubble obtained with the lubrication model agree fairly well with those extracted from the CFD simulations. This study shows that the Weber number of the flow, We = Ca Re , is the parameter that best describes the dynamics of the interfacial waves. When We 0.1, a larger number of wave crests becomes evident on the surface of the rear meniscus of the bubble. The liquid film thickness at the crests of the undulations thins considerably as the Reynolds number is increased, down to less than 60% of the value measured in the flat film region. This may significantly influence important environmental processes, such as the detachment and mobilization of micron-sized pollutants and pathogenic micro-organisms adhering at the pore's wall in unsaturated soil.

  13. Effects of gas liquid ratio on the atomization characteristics of gas-liquid swirl coaxial injectors

    Science.gov (United States)

    Kang, Zhongtao; Li, Qinglian; Zhang, Jiaqi; Cheng, Peng

    2018-05-01

    To understand the atomization characteristics and atomization mechanism of the gas-liquid swirl coaxial (GLSC) injector, a back-lighting photography technique has been employed to capture the instantaneous spray images with a high speed camera. The diameter and velocity of the droplets in the spray have been characterized with a Dantec Phase Doppler Anemometry (PDA) system. The effects of gas liquid ratio (GLR) on the spray pattern, Sauter mean diameter (SMD), diameter-velocity distribution and mass flow rate distribution were analyzed and discussed. The results show that the atomization of the GLSC injector is dominated by the film breakup when the GLR is small, and violent gas-liquid interaction when the GLR is large enough. The film breakup dominated spray can be divided into gas acceleration region and film breakup region while the violent gas-liquid interaction dominated spray can be divided into the gas acceleration region, violent gas-liquid interaction region and big droplets breakup region. The atomization characteristics of the GLSC injector is significantly influenced by the GLR. From the point of atomization performance, the increase of GLR has positive effects. It decreases the global Sauter mean diameter (GSMD) and varies the SMD distribution from a hollow cone shape (GLR = 0) to an inverted V shape, and finally slanted N shape. However, from the point of spatial distribution, the increase of GLR has negative effects, because the mass flow rate distribution becomes more nonuniform.

  14. Gas-liquid mass transfer and flow phenomena in the Peirce-Smith converter: a water model study

    Science.gov (United States)

    Zhao, Xing; Zhao, Hong-liang; Zhang, Li-feng; Yang, Li-qiang

    2018-01-01

    A water model with a geometric similarity ratio of 1:5 was developed to investigate the gas-liquid mass transfer and flow characteristics in a Peirce-Smith converter. A gas mixture of CO2 and Ar was injected into a NaOH solution bath. The flow field, volumetric mass transfer coefficient per unit volume ( Ak/V; where A is the contact area between phases, V is the volume, and k is the mass transfer coefficient), and gas utilization ratio ( η) were then measured at different gas flow rates and blow angles. The results showed that the flow field could be divided into five regions, i.e., injection, strong loop, weak loop, splashing, and dead zone. Whereas the Ak/V of the bath increased and then decreased with increasing gas flow rate, and η steadily increased. When the converter was rotated clockwise, both Ak/V and η increased. However, the flow condition deteriorated when the gas flow rate and blow angle were drastically increased. Therefore, these parameters must be controlled to optimal conditions. In the proposed model, the optimal gas flow rate and blow angle were 7.5 m3·h-1 and 10°, respectively.

  15. Taylor flow hydrodynamics in gas-liquid-solid micro reactors

    NARCIS (Netherlands)

    Warnier, M.J.F.

    2009-01-01

    Chemical reactions in which a gas phase component reacts with a liquid phase omponent at the surface of a solid catalyst are often encountered in chemical industry. The rate of such a gas-liquid-solid reaction is often limited by the mass transfer rate of the gas phase component, which depends on

  16. Gas-liquid flow splitting in T-junction with inclined lateral arm

    Science.gov (United States)

    Yang, Le-le; Liu, Shuo; Li, Hua; Zhang, Jian; Wu, Ying-xiang; Xu, Jing-yu

    2018-02-01

    This paper studies the gas-liquid flow splitting in T-junction with inclined lateral arm. The separation mechanism of the T-junction is related to the pressure distribution in the T-junction. It is shown that the separation efficiency strongly depends on the inclination angle, when the angle ranges from 0° to 30°, while not so strongly for angles in the range from 30° to 90° Increasing the number of connecting tubes is helpful for the gas-liquid separation, and under the present test conditions, with four connecting tubes, a good separation performance can be achieved. Accordingly, a multi-tube Y-junction separator with four connecting tubes is designed for the experimental investigation. A good agreement between the simulated and measured data shows that there is an optimal split ratio to achieve the best performance for the multi-tube Y-junction separator.

  17. A new method for ultrasound detection of interfacial position in gas-liquid two-phase flow.

    Science.gov (United States)

    Coutinho, Fábio Rizental; Ofuchi, César Yutaka; de Arruda, Lúcia Valéria Ramos; Neves, Flávio; Morales, Rigoberto E M

    2014-05-22

    Ultrasonic measurement techniques for velocity estimation are currently widely used in fluid flow studies and applications. An accurate determination of interfacial position in gas-liquid two-phase flows is still an open problem. The quality of this information directly reflects on the accuracy of void fraction measurement, and it provides a means of discriminating velocity information of both phases. The algorithm known as Velocity Matched Spectrum (VM Spectrum) is a velocity estimator that stands out from other methods by returning a spectrum of velocities for each interrogated volume sample. Interface detection of free-rising bubbles in quiescent liquid presents some difficulties for interface detection due to abrupt changes in interface inclination. In this work a method based on velocity spectrum curve shape is used to generate a spatial-temporal mapping, which, after spatial filtering, yields an accurate contour of the air-water interface. It is shown that the proposed technique yields a RMS error between 1.71 and 3.39 and a probability of detection failure and false detection between 0.89% and 11.9% in determining the spatial-temporal gas-liquid interface position in the flow of free rising bubbles in stagnant liquid. This result is valid for both free path and with transducer emitting through a metallic plate or a Plexiglas pipe.

  18. Modeling of Liquid Steel/Slag/Argon Gas Multiphase Flow During Tundish Open Eye Formation in a Two-Strand Tundish

    Science.gov (United States)

    Chatterjee, Saikat; Li, Donghui; Chattopadhyay, Kinnor

    2018-04-01

    Multiphase flows are frequently encountered in metallurgical operations. One of the most effective ways to understand these processes is by flow modeling. The process of tundish open eye (TOE) formation involves three-phase interaction between liquid steel, slag, and argon gas. The two-phase interaction involving argon gas bubbles and liquid steel can be modeled relatively easily using the discrete phase modeling technique. However, the effect of an upper slag layer cannot be captured using this approach. The presence of an upper buoyant phase can have a major effect on the behavior of TOEs. Hence, a multiphase model, including three phases, viz. liquid steel, slag, and argon gas, in a two-strand slab caster tundish, was developed to study the formation and evolution of TOEs. The volume of fluid model was used to track the interphase between liquid steel and slag phases, while the discrete phase model was used to trace the movement of the argon gas bubbles in liquid steel. The variation in the TOE areas with different amounts of aspirated argon gas was examined in the presence of an overlying slag phase. The mathematical model predictions were compared against steel plant measurements.

  19. Liquid-liquid mixing by gas injection in a pool configuration

    International Nuclear Information System (INIS)

    Corradini, M.L.

    1994-02-01

    An experimental apparatus was designed and constructed to study the mixing process of two immiscible liquids, in a pool configuration, by bottom gas injection. The apparatus consisted of a vertical pyrex conduit of 15.2 centimeters of internal diameter. To the lower part of the conduit was attached a porous plate through which the gas was injected. The experiments were photographically recorded. The pictures were digitized and a method was developed to quantify the mixing region thickness. This method requires knowledge of the void fraction, for each liquid, as a function of the superficial gas velocity. Because of this, void fraction was measured for the bubbly and churn flow regimes, in a pool configuration for every liquid. A new correlation, based on the drift flux model, is proposed for void fraction as a function of superficial gas velocity. It has been observed that mixing can start either in bubbly or churn flow regimes, depending on the liquid pair properties. Three mechanistic models were derived to aid in correlating the data, two for bubbly flow and one for churn flow. A transition region between these two flow regimes, was deduced, but not directly measured. A set of correlations was developed from the models and it is proposed to be implemented in current codes that model Molten Core Concrete Interactions (MCCI). The implications that the present work has on MCCI have been described. It can be deduced that mixing between the oxidic and the metallic phases will occur during the interaction

  20. Adiabatic gas-liquid flow

    International Nuclear Information System (INIS)

    Mayinger, F.

    1982-01-01

    The author starts by discussing the gas-fluidic mixture, its application and its special characteristics. The conservation theorems for these mixtures are then presented, including the continuity equation, the impulse equation, and energy balance. The type of flow in vertical channels, vertical downwards flow and flow in horizontal and inclined tubes is discussed followed by a short section on local volumetric steam contents and slip. The expressions for the slip and for the local volumetric steam contents are explained before discussing phase separation in nonflowing fluids. Pressure loss in tubes and channels is followed by discussion of pressure loss in various types of moulded bodies with particular reference to fuel rod bundles. In conclusion the author discusses pressure wave expansion, critical discharge and cross exchange in sub-divided channels. (A.N.K.)

  1. Two-phase gas bubble-liquid boundary layer flow along vertical and inclined surfaces

    International Nuclear Information System (INIS)

    Cheung, F.B.; Epstein, M.

    1985-01-01

    The behavior of a two-phase gas bubble liquid boundary layer along vertical and inclined porous surfaces with uniform gas injection is investigated experimentally and analytically. Using argon gas and water as the working fluids, a photographical study of the two-phase boundary layer flow has been performed for various angles of inclination ranging from 45 0 to 135 0 and gas injection rates ranging from 0.01 to 0.1 m/s. An integral method has been employed to solve the system of equations governing the two-phase motion. The effects of the gas injection rate and the angle of inclination on the growth of the boundary layer have been determined

  2. Distribution characteristics of interfacial parameter in downward gas-liquid two-phase flow in vertical circular tube

    International Nuclear Information System (INIS)

    Liu Guoqiang; Yan Changqi; Tian Daogui; Sun Licheng

    2014-01-01

    Experimental study was performed on distribution characteristics of interfacial parameters of downward gas-liquid flow in a vertical circular tube with the measurement by a two-sensor optical fiber probe. The test section is a circular pipe with the inner diameter of 50 mm and the length of 2000 mm. The superficial velocities of the gas and the liquid phases cover the ranges of 0.004-0.077 m/s and 0.43-0.71 m/s, respectively. The results show that the distributions of the interfacial parameters in downward bubbly flows are quite different from those in upward bubbly flows. For the case of upward flow, the parameters present the 'wall-peak' or 'core-peak' distributions, but for the case of downward flow, they show 'wall-peak' or 'wide-peak' distributions. The average value of void fraction in vertical downward flow is about 119.6%-145.0% larger than that in upward flow, and the interfacial area concentration is about 18.8%-82.5% larger than that in upward flow. The distribution of interfacial parameters shows an obvious tendency of uniformity. (authors)

  3. Liquid-Gas-Like Phase Transition in Sand Flow Under Microgravity

    Science.gov (United States)

    Huang, Yu; Zhu, Chongqiang; Xiang, Xiang; Mao, Wuwei

    2015-06-01

    In previous studies of granular flow, it has been found that gravity plays a compacting role, causing convection and stratification by density. However, there is a lack of research and analysis of the characteristics of different particles' motion under normal gravity contrary to microgravity. In this paper, we conduct model experiments on sand flow using a model test system based on a drop tower under microgravity, within which the characteristics and development processes of granular flow under microgravity are captured by high-speed cameras. The configurations of granular flow are simulated using a modified MPS (moving particle simulation), which is a mesh-free, pure Lagrangian method. Moreover, liquid-gas-like phase transitions in the sand flow under microgravity, including the transitions to "escaped", "jumping", and "scattered" particles are highlighted, and their effects on the weakening of shear resistance, enhancement of fluidization, and changes in particle-wall and particle-particle contact mode are analyzed. This study could help explain the surface geology evolution of small solar bodies and elucidate the nature of granular interaction.

  4. Hydrodynamics in a pressurized cocurrent gas-liquid trickle bed reactor

    NARCIS (Netherlands)

    Wammes, Wino J.A.; Westerterp, K.R.

    1991-01-01

    The influence of gas density on total external liquid hold-up, pressure drop and gas-liquid interfacial area, under trickle-flow conditions, and the transition to pulse flow have been investigated with nitrogen or helium as the gas phase up to 7.5 MPa. It is concluded that the hydrodynamics depends

  5. Gas-liquid flow around an obstacle in a vertical pipe

    International Nuclear Information System (INIS)

    Prasser, Horst-Michael; Beyer, Matthias; Frank, Thomas; Al Issa, Suleiman; Carl, Helmar; Pietruske, Heiko; Schuetz, Peter

    2008-01-01

    This paper presents a novel technique to study the two-phase flow field around an asymmetric obstruction in a vertical pipe with a nominal diameter of DN200. Main feature of the experiments is the shifting of a half-moon shaped diaphragm causing the obstruction along the axis of the pipe. In this way, the 3D void field is scanned with a stationary wire-mesh sensor that supplies data with a spatial resolution of 3 mm over the cross-section and a measuring frequency of 2.5 kHz. Besides the measurement of time-averaged void fraction fields and bubble-size distributions, novel data evaluation methods were developed to extract estimated liquid velocity profiles as well as lateral components of bubble velocities from the wire-mesh sensor data. The combination of void fraction fields and velocity profiles offer the opportunity to analyse a two-phase flow in a geometry that owns a series of features characteristic for complex components of power and chemical plant equipment. Such characteristics are sharp edges with flow separation, recirculation areas, jet formation, stagnation points and curved stream-lines. The tests were performed with an air-water flow at nearly ambient conditions and with a saturated steam-water mixture at 6.5 MPa. The superficial velocities of liquid and gas or, respectively, vapour were varied in a wide range. The flow structure upstream and downstream of the obstacle is characterized in detail. Bubble size dependent effects of bubble accumulation and migration are discussed on basis of void-fraction profiles decomposed into bubble-size classes. A pronounced influence of the fluid parameters was found in the behaviour of bubbles at the boundary of the jet coming from the non-obstructed part of the cross-section. In case of an air-water flow, bubbles are restrained from entering the jet, a phenomenon which was not observed in high-pressure steam-water flow. A detailed uncertainty analyse of the velocity assessments finishes the presented paper. A

  6. Numerical simulation of the heat transfer at cooling a high-temperature metal cylinder by a flow of a gas-liquid medium

    Science.gov (United States)

    Makarov, S. S.; Lipanov, A. M.; Karpov, A. I.

    2017-10-01

    The numerical modeling results for the heat transfer during cooling a metal cylinder by a gas-liquid medium flow in an annular channel are presented. The results are obtained on the basis of the mathematical model of the conjugate heat transfer of the gas-liquid flow and the metal cylinder in a two-dimensional nonstationary formulation accounting for the axisymmetry of the cooling medium flow relative to the cylinder longitudinal axis. To solve the system of differential equations the control volume approach is used. The flow field parameters are calculated by the SIMPLE algorithm. To solve iteratively the systems of linear algebraic equations the Gauss-Seidel method with under-relaxation is used. The results of the numerical simulation are verified by comparing the results of the numerical simulation with the results of the field experiment. The calculation results for the heat transfer parameters at cooling the high-temperature metal cylinder by the gas-liquid flow are obtained with accounting for evaporation. The values of the rate of cooling the cylinder by the laminar flow of the cooling medium are determined. The temperature change intensity for the metal cylinder is analyzed depending on the initial velocity of the liquid flow and the time of the cooling process.

  7. Application of radial basis function in densitometry of stratified regime of liquid-gas two phase flows

    International Nuclear Information System (INIS)

    Roshani, G.H.; Nazemi, E.; Roshani, M.M.

    2017-01-01

    In this paper, a novel method is proposed for predicting the density of liquid phase in stratified regime of liquid-gas two phase flows by utilizing dual modality densitometry technique and artificial neural network (ANN) model of radial basis function (RBF). The detection system includes a 137 Cs radioactive source and two NaI(Tl) detectors for registering transmitted and scattered photons. At the first step, a Monte Carlo simulation model was utilized to obtain the optimum position for the scattering detector in dual modality densitometry configuration. At the next step, an experimental setup was designed based on obtained optimum position for detectors from simulation in order to generate the required data for training and testing the ANN. The results show that the proposed approach could be successfully applied for predicting the density of liquid phase in stratified regime of gas-liquid two phase flows with mean relative error (MRE) of less than 0.701. - Highlights: • Density of liquid phase in stratified regime of two phase flows was predicted. • Combination of dual modality densitometry technique and ANN was utilized. • Detection system includes a 137 Cs radioactive source and two NaI(Tl) detectors. • MCNP simulation was done to obtain the optimum position for the scattering detector. • An experimental setup was designed to generate the required data for training the ANN.

  8. Generation and characterization of gas bubbles in liquid metals

    International Nuclear Information System (INIS)

    Eckert, S.; Gerbeth, G.; Witke, W.

    1996-01-01

    There is an ongoing research performed in the RCR on local transport phenomena in turbulent liquid metal (LM) duct flows exposed to external magnetic fields. In this context so-called MHD flow phenomena can be observed, which are unknown in usual hydraulic engineering. The field of interest covers also the influence of magnetic fields on the behaviour of liquid metal - gas mixtures. Profound knowledge on these LMMHD two-phase flow plays an important role in a variety of technological applications, in particular, in the design of Liquid-Metal MHD generators or for several metallurgical processes employing gas-stirred reactors. However, the highly empirical nature of two-phase flow analysis gives little hope for the prediction of MHD two-phase flows without extensive experimental data. A summary is given about the authors research activities focussing on two directions: (a) Momentum transfer between gas and liquid metal in a bubbly flow regime to investigate the influence of the external magnetic field on the velocity slip ration S (b) Peculiarities of the MHD turbulence to use small gas bubbles as local tracers in order to study the turbulent mass transfer

  9. Hydrodynamic characteristics of a two-phase gas-liquid flow upward through a fixed bed of spherical particles

    Directory of Open Access Journals (Sweden)

    VELIZAR D. STANKOVIC

    2001-01-01

    Full Text Available The influence of an electrochemically generated gas phase on the hydrodynamic characteristics of a three-phase system has been examined. The two-phase fluid, (gas-liquid, in which the liquid phase is the continuous one, flows through a packed bed with glass spheres. The influence of the liquid velocity was examined, as well as the gas velocity and particle diameter on the pressure drop through the fixed bed. It was found that with increasing liquid velocity (wl = 0.0162–0.03 m/s, the relative pressure drop decreases through the fixed bed. With increasing current density, the pressure drop increases, since greater gas quantities stay behind in the fixed bed. Besides, it was found that with decreasing diameter of the glass particles, the relative pressure drop also decreases. The relationship betweeen the experimentally obtained friction factor and the Reynolds number was established.

  10. Heat transfer by gas-liquid mixture in forced turbulent flow with weak vaporization of the liquid phase (1962); Transfert de chaleur par melange de liquide et de gaz en convection forcee turbulente avec faible vaporisation de la phase liquide (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Huyghe, J; Mondin, G [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1962-07-01

    The present study deals with measures of heat transfer and pressure drop in two-phase liquid flow. The stream is of annular dispersed type, obtained by introducing a small quantity of liquid in a gas turbulent flow. The heat transfer experiments are performed without vaporization of the liquid phase. A notable improvement of the heat transfer coefficient of such a stream is observed, compared with a gas-alone or liquid-alone flow. The improvement concerning the gas-alone is of about 20 when it is compared with the same gas Reynolds's number, of about 8 when it is compared with the same total mass flow rate. A hydrodynamic study of the flow pattern lets us know the original structure of the flow, and allows to foresee the experimental results by means of a simplified theory. (authors) [French] II est fait etat de mesures de transfert thermique et de perte de charge dans un ecoulement en double phase gaz-liquide. L'ecoulement est du type annulaire disperse, obtenu par injection d'une faible quantite de liquide dans un ecoulement gazeux en regime turbulent. Les experiences de transfert thermique sont menees sans vaporisation de la phase liquide. On note une amelioration sensible du coefficient de transfert thermique dans un tel ecoulement par rapport a un ecoulement de gaz seul ou de liquide seul. L'augmentation est de l'ordre de 20 par rapport au gaz seul si on opere a meme nombre de REYNOLDS du gaz, de l'ordre de 8 si on opere a meme debit massique total. Une etude hydrodynamique rapide de l'ecoulement permet de connaitre la structure originale de l'ecoulement, puis de prevoir par une theorie simplifiee le phenomene thermique observe. (auteurs)

  11. Wire-mesh sensor, ultrasound and high-speed videometry applied for the characterization of horizontal gas-liquid slug flow

    Science.gov (United States)

    Ofuchi, C. Y.; Morales, R. E. M.; Arruda, L. V. R.; Neves, F., Jr.; Dorini, L.; do Amaral, C. E. F.; da Silva, M. J.

    2012-03-01

    Gas-liquid flows occur in a broad range of industrial applications, for instance in chemical, petrochemical and nuclear industries. Correct understating of flow behavior is crucial for safe and optimized operation of equipments and processes. Thus, measurement of gas-liquid flow plays an important role. Many techniques have been proposed and applied to analyze two-phase flows so far. In this experimental research, data from a wire-mesh sensor, an ultrasound technique and high-speed camera are used to study two-phase slug flows in horizontal pipes. The experiments were performed in an experimental two-phase flow loop which comprises a horizontal acrylic pipe of 26 mm internal diameter and 9 m length. Water and air were used to produce the two-phase flow and their flow rates are separately controlled to produce different flow conditions. As a parameter of choice, translational velocity of air bubbles was determined by each of the techniques and comparatively evaluated along with a mechanistic flow model. Results obtained show good agreement among all techniques. The visualization of flow obtained by the different techniques is also presented.

  12. Simulation Of Gas Focused Liquid Jets

    OpenAIRE

    Zahoor, Rizwan

    2018-01-01

    The main aim of dissertation is to develop an experimentally verified computational fluid dynamic (CFD) model of micron-sized liquid jet, produced by an injection molded Gas Dynamic Virtual Nozzle (GDVN). In these nozzles, liquid jets are efficiently orientedly transporting mass and momentum. They are produced by intelligently projecting hydrodynamic focusing effect from a high-speed stream of a co-flowing lower density and lower viscosity gas on a stream of liquid from a feeding capillary. L...

  13. Geometry of thin liquid sheet flows

    Science.gov (United States)

    Chubb, Donald L.; Calfo, Frederick D.; Mcconley, Marc W.; Mcmaster, Matthew S.; Afjeh, Abdollah A.

    1994-01-01

    Incompresible, thin sheet flows have been of research interest for many years. Those studies were mainly concerned with the stability of the flow in a surrounding gas. Squire was the first to carry out a linear, invicid stability analysis of sheet flow in air and compare the results with experiment. Dombrowski and Fraser did an experimental study of the disintegration of sheet flows using several viscous liquids. They also detected the formulation of holes in their sheet flows. Hagerty and Shea carried out an inviscid stability analysis and calculated growth rates with experimental values. They compared their calculated growth rates with experimental values. Taylor studied extensively the stability of thin liquid sheets both theoretically and experimentally. He showed that thin sheets in a vacuum are stable. Brown experimentally investigated thin liquid sheet flows as a method of application of thin films. Clark and Dumbrowski carried out second-order stability analysis for invicid sheet flows. Lin introduced viscosity into the linear stability analysis of thin sheet flows in a vacuum. Mansour and Chigier conducted an experimental study of the breakup of a sheet flow surrounded by high-speed air. Lin et al. did a linear stability analysis that included viscosity and a surrounding gas. Rangel and Sirignano carried out both a linear and nonlinear invisid stability analysis that applies for any density ratio between the sheet liquid and the surrounding gas. Now there is renewed interest in sheet flows because of their possible application as low mass radiating surfaces. The objective of this study is to investigate the fluid dynamics of sheet flows that are of interest for a space radiator system. Analytical expressions that govern the sheet geometry are compared with experimental results. Since a space radiator will operate in a vacuum, the analysis does not include any drag force on the sheet flow.

  14. Hydrogen extraction from liquid lithium-lead alloy by gas-liquid contact method

    International Nuclear Information System (INIS)

    Xie Bo; Weng Kuiping; Hou Jianping; Yang Guangling; Zeng Jun

    2013-01-01

    Hydrogen extraction experiment from liquid lithium-lead alloy by gas-liquid contact method has been carried out in own liquid lithium-lead bubbler (LLLB). Experimental results show that, He is more suitable than Ar as carrier gas in the filler tower. The higher temperature the tower is, the greater hydrogen content the tower exports. Influence of carrier gas flow rate on the hydrogen content in the export is jagged, no obvious rule. Although the difference between experimental results and literature data, but it is feasible that hydrogen isotopes extraction experiment from liquid lithium-lead by gas-liquid contact method, and the higher extraction efficiency increases with the growth of the residence time of the alloy in tower. (authors)

  15. Selective gas absorption by ionic liquids

    DEFF Research Database (Denmark)

    Shunmugavel, Saravanamurugan; Kegnæs, Søren; Due-Hansen, Johannes

    2010-01-01

    Reversible absorption performance for the flue gas components CO 2, NO and SO2 has been tested for several different ionic liquids (ILs) at different temperatures and flue gas compositions. Furthermore, different porous, high surface area carriers have been applied as supports for the ionic liquids...... to obtain Supported Ionic Liquid-Phase (SILP) absorber materials. The use of solid SILP absorbers with selected ILs were found to significantly improve the absorption capacity and sorption dynamics at low flue gas concentration, thus making the applicability of ILs viable in technical, continuous flow...... processes for flue gas cleaning. The results show that CO 2, NO and SO2 can be reversible and selective absorbed using different ILs and that Supported Ionic Liquid-Phase (SILP) absorbers are promising materials for industrial flue gas cleaning. Absorption/desorption dynamics can be tuned by temperatures...

  16. Liquid oil production from shale gas condensate reservoirs

    Science.gov (United States)

    Sheng, James J.

    2018-04-03

    A process of producing liquid oil from shale gas condensate reservoirs and, more particularly, to increase liquid oil production by huff-n-puff in shale gas condensate reservoirs. The process includes performing a huff-n-puff gas injection mode and flowing the bottom-hole pressure lower than the dew point pressure.

  17. Characterizing the correlations between local phase fractions of gas-liquid two-phase flow with wire-mesh sensor.

    Science.gov (United States)

    Tan, C; Liu, W L; Dong, F

    2016-06-28

    Understanding of flow patterns and their transitions is significant to uncover the flow mechanics of two-phase flow. The local phase distribution and its fluctuations contain rich information regarding the flow structures. A wire-mesh sensor (WMS) was used to study the local phase fluctuations of horizontal gas-liquid two-phase flow, which was verified through comparing the reconstructed three-dimensional flow structure with photographs taken during the experiments. Each crossing point of the WMS is treated as a node, so the measurement on each node is the phase fraction in this local area. An undirected and unweighted flow pattern network was established based on connections that are formed by cross-correlating the time series of each node under different flow patterns. The structure of the flow pattern network reveals the relationship of the phase fluctuations at each node during flow pattern transition, which is then quantified by introducing the topological index of the complex network. The proposed analysis method using the WMS not only provides three-dimensional visualizations of the gas-liquid two-phase flow, but is also a thorough analysis for the structure of flow patterns and the characteristics of flow pattern transition. This article is part of the themed issue 'Supersensing through industrial process tomography'. © 2016 The Author(s).

  18. Undulations on the surface of elongated bubbles in confined gas-liquid flows

    Science.gov (United States)

    Magnini, M.; Ferrari, A.; Thome, J. R.; Stone, H. A.

    2017-08-01

    A systematic analysis is presented of the undulations appearing on the surface of long bubbles in confined gas-liquid flows. CFD simulations of the flow are performed with a self-improved version of the open-source solver ESI OpenFOAM (release 2.3.1), for Ca =0.002 -0.1 and Re =0.1 -1000 , where Ca =μ U /σ and Re =2 ρ U R /μ , with μ and ρ being, respectively, the viscosity and density of the liquid, σ the surface tension, U the bubble velocity, and R the tube radius. A model, based on an extension of the classical axisymmetric Bretherton theory, accounting for inertia and for the curvature of the tube's wall, is adopted to better understand the CFD results. The thickness of the liquid film, and the wavelength and decay rate of the undulations extracted from the CFD simulations, agree well with those obtained with the theoretical model. Inertial effects appear when the Weber number of the flow We =Ca Re =O (10-1) and are manifest by a larger number of undulation crests that become evident on the surface of the rear meniscus of the bubble. This study demonstrates that the necessary bubble length for a flat liquid film region to exist between the rear and front menisci rapidly increases above 10 R when Ca >0.01 and the value of the Reynolds number approaches 1000.

  19. A New Void Fraction Measurement Method for Gas-Liquid Two-Phase Flow in Small Channels

    Directory of Open Access Journals (Sweden)

    Huajun Li

    2016-01-01

    Full Text Available Based on a laser diode, a 12 × 6 photodiode array sensor, and machine learning techniques, a new void fraction measurement method for gas-liquid two-phase flow in small channels is proposed. To overcome the influence of flow pattern on the void fraction measurement, the flow pattern of the two-phase flow is firstly identified by Fisher Discriminant Analysis (FDA. Then, according to the identification result, a relevant void fraction measurement model which is developed by Support Vector Machine (SVM is selected to implement the void fraction measurement. A void fraction measurement system for the two-phase flow is developed and experiments are carried out in four different small channels. Four typical flow patterns (including bubble flow, slug flow, stratified flow and annular flow are investigated. The experimental results show that the development of the measurement system is successful. The proposed void fraction measurement method is effective and the void fraction measurement accuracy is satisfactory. Compared with the conventional laser measurement systems using standard laser sources, the developed measurement system has the advantages of low cost and simple structure. Compared with the conventional void fraction measurement methods, the proposed method overcomes the influence of flow pattern on the void fraction measurement. This work also provides a good example of using low-cost laser diode as a competent replacement of the expensive standard laser source and hence implementing the parameter measurement of gas-liquid two-phase flow. The research results can be a useful reference for other researchers’ works.

  20. A New Void Fraction Measurement Method for Gas-Liquid Two-Phase Flow in Small Channels.

    Science.gov (United States)

    Li, Huajun; Ji, Haifeng; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing; Wu, Guohua

    2016-01-27

    Based on a laser diode, a 12 × 6 photodiode array sensor, and machine learning techniques, a new void fraction measurement method for gas-liquid two-phase flow in small channels is proposed. To overcome the influence of flow pattern on the void fraction measurement, the flow pattern of the two-phase flow is firstly identified by Fisher Discriminant Analysis (FDA). Then, according to the identification result, a relevant void fraction measurement model which is developed by Support Vector Machine (SVM) is selected to implement the void fraction measurement. A void fraction measurement system for the two-phase flow is developed and experiments are carried out in four different small channels. Four typical flow patterns (including bubble flow, slug flow, stratified flow and annular flow) are investigated. The experimental results show that the development of the measurement system is successful. The proposed void fraction measurement method is effective and the void fraction measurement accuracy is satisfactory. Compared with the conventional laser measurement systems using standard laser sources, the developed measurement system has the advantages of low cost and simple structure. Compared with the conventional void fraction measurement methods, the proposed method overcomes the influence of flow pattern on the void fraction measurement. This work also provides a good example of using low-cost laser diode as a competent replacement of the expensive standard laser source and hence implementing the parameter measurement of gas-liquid two-phase flow. The research results can be a useful reference for other researchers' works.

  1. CFD-DEM based numerical simulation of liquid-gas-particle mixture flow in dam break

    Science.gov (United States)

    Park, Kyung Min; Yoon, Hyun Sik; Kim, Min Il

    2018-06-01

    This study investigates the multiphase flow of a liquid-gas-particle mixture in dam break. The open source codes, OpenFOAM and CFDEMproject, were used to reproduce the multiphase flow. The results of the present study are compared with those of previous results obtained by numerical and experimental methods, which guarantees validity of present numerical method to handle the multiphase flow. The particle density ranging from 1100 to 2500 kg/m3 is considered to investigate the effect of the particle density on the behavior of the free-surface and the particles. The particle density has no effect on the liquid front, but it makes the particle front move with different velocity. The time when the liquid front reach at the opposite wall is independent of particle density. However, such time for particle front decrease as particle density increases, which turned out to be proportional to particle density. Based on these results, we classified characteristics of the movement by the front positions of the liquid and the particles. Eventually, the response of the free-surface and particles to particle density is identified by three motion regimes of the advancing, overlapping and delaying motions.

  2. Influence of the gas-liquid flow configuration in the absorption column on photosynthetic biogas upgrading in algal-bacterial photobioreactors.

    Science.gov (United States)

    Toledo-Cervantes, Alma; Madrid-Chirinos, Cindy; Cantera, Sara; Lebrero, Raquel; Muñoz, Raúl

    2017-02-01

    The potential of an algal-bacterial system consisting of a high rate algal pond (HRAP) interconnected to an absorption column (AC) via recirculation of the cultivation broth for the upgrading of biogas and digestate was investigated. The influence of the gas-liquid flow configuration in the AC on the photosynthetic biogas upgrading process was assessed. AC operation in a co-current configuration enabled to maintain a biomass productivity of 15gm -2 d -1 , while during counter-current operation biomass productivity decreased to 8.7±0.5gm -2 d -1 as a result of trace metal limitation. A bio-methane composition complying with most international regulatory limits for injection into natural gas grids was obtained regardless of the gas-liquid flow configuration. Furthermore, the influence of the recycling liquid to biogas flowrate (L/G) ratio on bio-methane quality was assessed under both operational configurations obtaining the best composition at an L/G ratio of 0.5 and co-current flow operation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Secondary Flow Patterns of Liquid Ejector with Computational Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Kwisung; Yun, Jinwon; Yu, Sangseok [Chungnam National University, Daejeon (Korea, Republic of); Sohn, Inseok [COAVIS, Sejong (Korea, Republic of); Seo, Yongkyo [Korea Automotive Technology Institute, Cheonan (Korea, Republic of)

    2015-02-15

    An ejector is a type of non-powered pump that is used to supply a secondary flow via the ejection of a primary flow. It is utilized in many industrial fields, and is used for fueling the vehicle because of less failures and simple structure. Since most of ejectors in industry are gas-to-gas and liquid to gas ejector, many research activities have been reported in optimization of gas ejector. On the other hand, the liquid ejector is also applied in many industry but few research has been reported. The liquid ejector occurs cavitation, and it causes damage of parts. Cavitation has bees observed at the nozzle throat at the specified pressure. In this study, a two-dimensional axisymmetric simulation of a liquid-liquid ejector was carried out using five different parameters. The angle of the nozzle plays an important role in the cavitation of a liquid ejector, and the performance characteristics of the flow ratio showed that an angle of 35° was the most advantageous. The simulation results showed that the performance of the liquid ejector and the cavitation effect have to be considered simultaneously.

  4. A method for identifying gas-liquid two-phase flow patterns on the basis of wavelet packet multi-scale information entropy and HMM

    International Nuclear Information System (INIS)

    Zhou Yunlong; Zhang Xueqing; Gao Yunpeng; Cheng Yue

    2009-01-01

    For studying flow regimes of gas/liquid two-phase in a vertical upward pipe, the conductance fluctuation information of four typical flow regimes was collected by a measuring the system with self-made multiple conductivity probes. Owing to the non-stationarity of conductance fluctuation signals of gas-liquid two-phase flow, a kind of' flow regime identification method based on wavelet packet Multi-scale Information Entropy and Hidden Markov Model (HMM) was put forward. First of all, the collected conductance fluctuation signals were decomposed into eight different frequency bands signals. Secondly, the wavelet packet multi-scale information entropy of different frequency bands signals were regarded as the input characteristic vectors of all states HMM which had been trained. In the end the regime identification of' the gas-liquid two-phase flow could be performed. The study showed that the method that HMM was applied to identify the flow regime was superior to the one that BP neural network was used, and the results proved that the method was efficient and feasible. (authors)

  5. [CFD numerical simulation onto the gas-liquid two-phase flow behavior during vehicle refueling process].

    Science.gov (United States)

    Chen, Jia-Qing; Zhang, Nan; Wang, Jin-Hui; Zhu, Ling; Shang, Chao

    2011-12-01

    With the gradual improvement of environmental regulations, more and more attentions are attracted to the vapor emissions during the process of vehicle refueling. Research onto the vehicle refueling process by means of numerical simulation has been executed abroad since 1990s, while as it has never been involved so far domestically. Through reasonable simplification about the physical system of "Nozzle + filler pipe + gasoline storage tank + vent pipe" for vehicle refueling, and by means of volume of fluid (VOF) model for gas-liquid two-phase flow and Re-Normalization Group kappa-epsilon turbulence flow model provided in commercial computational fluid dynamics (CFD) software Fluent, this paper determined the proper mesh discretization scheme and applied the proper boundary conditions based on the Gambit software, then established the reasonable numerical simulation model for the gas-liquid two-phase flow during the refueling process. Through discussing the influence of refueling velocity on the static pressure of vent space in gasoline tank, the back-flowing phenomenon has been revealed in this paper. It has been demonstrated that, the more the flow rate and the refueling velocity of refueling nozzle is, the higher the gross static pressure in the vent space of gasoline tank. In the meanwhile, the variation of static pressure in the vent space of gasoline tank can be categorized into three obvious stages. When the refueling flow rate becomes higher, the back-flowing phenomenon of liquid gasoline can sometimes be induced in the head section of filler pipe, thus making the gasoline nozzle pre-shut-off. Totally speaking, the theoretical work accomplished in this paper laid some solid foundation for self-researching and self-developing the technology and apparatus for the vehicle refueling and refueling emissions control domestically.

  6. Behaviour of liquid films and flooding in counter-current two-phase flow, (1)

    International Nuclear Information System (INIS)

    Suzuki, Shin-ichi; Ueda, Tatsuhiro.

    1978-01-01

    This paper reports on the results of study of the behavior of liquid film and flooding in counter-current two phase flow, and the flow speed of gas phase was measured over the wide ranges of tube diameter, tube length, amount of liquid flow, viscosity and surface tension. Liquid samples used for this experiment were water, glycerol, and second octyl alcohol. The phenomena were observed with a high speed camera. The maximum thickness of liquid film was measured, and the effects of various factors on the flooding were investigated. The results of investigation were as follows. The big waves which cause the flooding were developed by the interaction of one of the waves on liquid film surface with gas phase flow. The flow speed of gas phase at the time of beginning of flooding increases with the reduction of amount of liquid flow and the increase of tube diameter. The flooding flow speed is reduced with the increase of tube length. The larger maximum film thickness at the time of no gas phase flow causes flooding at low gas phase flow speed. (Kato, T.)

  7. Thin liquid films with time-dependent chemical reactions sheared by an ambient gas flow

    Science.gov (United States)

    Bender, Achim; Stephan, Peter; Gambaryan-Roisman, Tatiana

    2017-08-01

    Chemical reactions in thin liquid films are found in many industrial applications, e.g., in combustion chambers of internal combustion engines where a fuel film can develop on pistons or cylinder walls. The reactions within the film and the turbulent outer gas flow influence film stability and lead to film breakup, which in turn can lead to deposit formation. In this work we examine the evolution and stability of a thin liquid film in the presence of a first-order chemical reaction and under the influence of a turbulent gas flow. Long-wave theory with a double perturbation analysis is used to reduce the complexity of the problem and obtain an evolution equation for the film thickness. The chemical reaction is assumed to be slow compared to film evolution and the amount of reactant in the film is limited, which means that the reaction rate decreases with time as the reactant is consumed. A linear stability analysis is performed to identify the influence of reaction parameters, material properties, and environmental conditions on the film stability limits. Results indicate that exothermic reactions have a stabilizing effect whereas endothermic reactions destabilize the film and can lead to rupture. It is shown that an initially unstable film can become stable with time as the reaction rate decreases. The shearing of the film by the external gas flow leads to the appearance of traveling waves. The shear stress magnitude has a nonmonotonic influence on film stability.

  8. State-of-the-art review of liquid loading in gas wells

    Energy Technology Data Exchange (ETDEWEB)

    Falcone, G. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). ITE; Barbosa, J.R. Jr. [Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil). Dept. of Mechanical Engineering

    2013-08-01

    Gas wells suffering from liquid loading are incapable of removing the liquid associated with produced gas from the wellbore. This phenomenon is initiated when the upward gas velocity in the well falls below a critical value at which point the liquid that was initially flowing upwards, begins to fall back. This liquid accumulates downhole, where it increases the hydrostatic back-pressure on the reservoir, destabilises the multiphase flow in the well (following flow regime changes), decreases production rate and, in severe cases, kills the well. The typical liquid loading sequence begins with a gas flow rate that is high enough to transport all liquids to surface and there is no liquid fall-back in the well. However, as the gas velocity slows or the liquid content in the well rises, there is insufficient energy in the well to carry all liquids to surface and some begins to flow backwards. As the hydrostatic head downhole increases, the liquid column that has accumulated in the well can re-enter the near-wellbore region of the reservoir. This results in the well becoming 'unloaded' so that it can flow once more, with the gas carrying all liquids to surface. However, the reinjection of liquids into the reservoir may cause formation damage, which will impair the well productivity. This cycle continues, providing the typical intermittent response of liquid-loaded gas wells, until the reservoir potential starts to fall or the liquid yield rises. Diagnosing liquid loading is often difficult as the affected well(s) may continue production without any substantial performance impairment for a long period of time. Typical symptoms of liquid loading include sharp drops in the cumulative production decline curve, the onset of liquid slugs in the surface facilities, abrupt changes in the flowing pressure gradient, low temperature spikes at the wellhead and declining water production or condensate-gas-ratio. Many remedial lifting options have been developed for use in

  9. Visualization of velocity field and phase distribution in gas-liquid two-phase flow by NMR imaging

    International Nuclear Information System (INIS)

    Matsui, G.; Monji, H.; Obata, J.

    2004-01-01

    NMR imaging has been applied in the field of fluid mechanics, mainly single phase flow, to visualize the instantaneous flow velocity field. In the present study, NMR imaging was used to visualize simultaneously both the instantaneous phase structure and velocity field of gas-liquid two-phase flow. Two methods of NMR imaging were applied. One is useful to visualize both the one component of liquid velocity and the phase distribution. This method was applied to horizontal two-phase flow and a bubble rising in stagnant oil. It was successful in obtaining some pictures of velocity field and phase distribution on the cross section of the pipe. The other is used to visualize a two-dimensional velocity field. This method was applied to a bubble rising in a stagnant water. The velocity field was visualized after and before the passage of a bubble at the measuring cross section. Furthermore, the distribution of liquid velocity was obtained. (author)

  10. Summary on experimental methods for statistical transient analysis of two-phase gas-liquid flow

    International Nuclear Information System (INIS)

    Delhaye, J.M.; Jones, O.C. Jr.

    1976-06-01

    Much work has been done in the study of two-phase gas-liquid flows. Although it has been recognized superficially that such flows are not homogeneous in general, little attention has been paid to the inherent discreteness of the two-phase systems. Only relatively recently have fluctuating characteristics of two-phase flows been studied in detail. As a result, new experimental devices and techniques have been developed for use in measuring quantities previously ignored. This report reviews and summarizes most of these methods in an effort to emphasize the importance of the fluctuating nature of these flows and as a guide to further research in this field

  11. Contribution to the dynamical study of gas-liquid two-phase flows

    International Nuclear Information System (INIS)

    Lewi, Joseph.

    1975-01-01

    A single system of equations valid for two-phase flows at any time and anywhere was searched for. The mathematical theory of distributions was used. The results obtained was applied to the turbulent flow of an emulsion in a canal of constant section. It is shown that the use of distribution conservation equations makes it possible to determine the shapes of the mean velocity profiles, to obtain a relation between the friction coefficient and a Reynolds number introduced in a logical way, and to express the total pressure drop in the canal. Three experiments were carried out to compare the performance of various optical methods used for displaying bubble liquid-gas flows, and, within the limits of these methods, to study the interaction between the bubbles and the sensible end of variable impedance probe, and the granulometry of the emulsion in the vicinity of the probe [fr

  12. Statistical parameter characteristics of gas-phase fluctuations for gas-liquid intermittent flow

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, G.; Monji, H.; Takaguchi, M. [Univ. of Tsukuba (Japan)

    1995-09-01

    This study deals with theoretical analysis on the general behaviour of statistical parameters of gas-phase fluctuations and comparison of statistical parameter characteristics for the real void fraction fluctuations measured with those for the wave form modified the real fluctuations. In order to investigate the details of the relation between the behavior of the statistical parameters in real intermittent flow and analytical results obtained from information on the real flow, the distributions of statistical parameters for general fundamental wave form of gas-phase fluctuations are discussed in detail. By modifying the real gas-phase fluctuations to a trapezoidaly wave, the experimental results can be directly compared with the analytical results. The analytical results for intermittent flow show that the wave form parameter, and the total amplitude of void fraction fluctuations, affects strongly on the statistical parameter characteristics. The comparison with experiment using nitrogen gas-water intermittent flow suggests that the parameters of skewness and excess may be better as indicators of flow pattern. That is, the macroscopic nature of intermittent flow can be grasped by the skewness and the excess, and the detailed flow structure may be described by the mean and the standard deviation.

  13. Statistical parameter characteristics of gas-phase fluctuations for gas-liquid intermittent flow

    International Nuclear Information System (INIS)

    Matsui, G.; Monji, H.; Takaguchi, M.

    1995-01-01

    This study deals with theoretical analysis on the general behaviour of statistical parameters of gas-phase fluctuations and comparison of statistical parameter characteristics for the real void fraction fluctuations measured with those for the wave form modified the real fluctuations. In order to investigate the details of the relation between the behavior of the statistical parameters in real intermittent flow and analytical results obtained from information on the real flow, the distributions of statistical parameters for general fundamental wave form of gas-phase fluctuations are discussed in detail. By modifying the real gas-phase fluctuations to a trapezoidaly wave, the experimental results can be directly compared with the analytical results. The analytical results for intermittent flow show that the wave form parameter, and the total amplitude of void fraction fluctuations, affects strongly on the statistical parameter characteristics. The comparison with experiment using nitrogen gas-water intermittent flow suggests that the parameters of skewness and excess may be better as indicators of flow pattern. That is, the macroscopic nature of intermittent flow can be grasped by the skewness and the excess, and the detailed flow structure may be described by the mean and the standard deviation

  14. Measurement of Liquid-Metal Two-Phase Flow with a Dynamic Neutron Radiography

    International Nuclear Information System (INIS)

    Cha, J. E.; Lim, I. C.; Kim, H. R.; Kim, C. M.; Nam, H. Y.; Saito, Y.

    2005-01-01

    The dynamic neutron radiography(DNR) has complementary characteristics to X-ray radiography and is suitable to visualization and measurement of a multi-phase flow research in a metallic duct and liquid metal flow. The flow-field information of liquid metal system is very important for the safety analysis of fast breeder reactor and the design of the spallation target of accelerator driven system. A DNR technique was applied to visualize the flow field in the gas-liquid metal two-phase flow with the HANARO-beam facility. The lead bismuth eutectic and the nitrogen gas were used to construct the two-phase flow field in the natural circulation U-channel. The two-phase flow images in the riser were taken at various combinations of the liquid flow and gas flow with high frame-rate neutron radiography at 1000 fps

  15. Horizontal liquid film-mist two phase flow, (1)

    International Nuclear Information System (INIS)

    Akagawa, Koji; Sakaguchi, Tadashi; Fujii, Terushige; Nakatani, Yoji; Nakaseko, Kosaburo.

    1979-01-01

    The characteristics of liquid film in annular spray flow, the generation of droplets from liquid film and the transport of droplets to a wall are the important matters in the planning and design of nuclear reactor cooling system and the channels of steam generators. The study on the liquid film spray flow is scarce, and its characteristics are not yet elucidated. The purpose of this series of studies is to clarify the characteristics of liquid film, the generation, diffusion and distribution of droplets and pressure loss in the liquid film spray flow composed of the liquid film on the lower wall and spraying gas flow in a rectangular, horizontal channel. In this paper, the concentration distribution and the diffusion coefficient of droplets on a cross section in the region of flow completion are reported. The experimental apparatuses and the experimental method, the flow rate of droplets and the velocity distribution of gas phase, the concentration distribution and the diffusion coefficient of droplets, and the diameter of generated droplets are explained. The equation for the concentration distribution of droplets using dimensionless characteristic value was derived. The mean diffusion coefficient of droplets was constant on a cross section, and the effects of gravity and turbulent diffusion can be evaluated. (Kako, I.)

  16. Gas holdup in a reciprocating plate bioreactor: Non-Newtonian - liquid phase

    Directory of Open Access Journals (Sweden)

    Naseva Olivera S.

    2002-01-01

    Full Text Available The gas holdup was studied in non-newtonian liquids in a gas-liquid and gas-liquid-solid reciprocating plate bioreactor. Aqueous solutions of carboxy methyl cellulose (CMC; Lucel, Lučane, Yugoslavia of different degrees of polymerization (PP 200 and PP 1000 and concentration (0,5 and 1%, polypropylene spheres (diameter 8.3 mm; fraction of spheres: 3.8 and 6.6% by volume and air were used as the liquid, solid and gas phase. The gas holdup was found to be dependent on the vibration rate, the superficial gas velocity, volume fraction of solid particles and Theological properties of the liquid ohase. Both in the gas-liquid and gas-liquid-solid systems studied, the gas holdup increased with increasing vibration rate and gas flow rate. The gas holdup was higher in three-phase systems than in two-phase ones under otter operating conditions being the same. Generally the gas holdup increased with increasing the volume fraction of solid particles, due to the dispersion action of the solid particles, and decreased with increasing non-Newtonian behaviour (decreasing flow index i.e. with increasing degree of polymerization and solution concentration of CMC applied, as a result of gas bubble coalescence.

  17. Detection of gas entrainment into liquid metals

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, T., E-mail: t.vogt@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Fluid Dynamics, 01328 Dresden (Germany); Boden, S. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Fluid Dynamics, 01328 Dresden (Germany); Andruszkiewicz, A. [Faculty of Mechanical and Power Engineering, Wroclaw University of Technology (Poland); Eckert, K. [Technische Universität Dresden, Institute of Fluid Mechanics, 01062 Dresden (Germany); Eckert, S.; Gerbeth, G. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Fluid Dynamics, 01328 Dresden (Germany)

    2015-12-01

    Highlights: • We present liquid metal experiments dedicated to gas entrainment on the free surface. • Ultrasonic and X-ray attenuation techniques have been used to study the mechanisms of gas entrainment. • A comparison between bubbly flow in water and GaInSn showed substantial differences. • Our results emphasize the importance of liquid metal experiments which are able to provide a suitable data base for numerical code validation. - Abstract: Entrainment of cover gas into the liquid metal coolant is one of the principal safety issues in the design of innovative liquid metal-cooled fast reactors. We present generic experimental studies of this phenomenon in low-melting metals. Ultrasonic and X-ray diagnostic tools were considered for a visualization of gas entrainment at the free surface of the melt. Laboratory experiments were conducted using the eutectic alloy GaInSn, which is liquid at room temperature. Vortex-activated entrainment of air at the free surface of a rotating flow was revealed by ultrasonic techniques. X-ray radioscopy was used to visualize the behavior of argon bubbles inside a slit geometry. The measurements reveal distinct differences between water and GaInSn, especially with respect to the process of bubble formation and the coalescence and breakup of bubbles. Our results emphasize the importance of liquid metal experiments which are able to provide a suitable data base for numerical code validation.

  18. Gas transfer in a bubbly wake flow

    Science.gov (United States)

    Karn, A.; Gulliver, J. S.; Monson, G. M.; Ellis, C.; Arndt, R. E. A.; Hong, J.

    2016-05-01

    The present work reports simultaneous bubble size and gas transfer measurements in a bubbly wake flow of a hydrofoil, designed to be similar to a hydroturbine blade. Bubble size was measured by a shadow imaging technique and found to have a Sauter mean diameter of 0.9 mm for a reference case. A lower gas flow rate, greater liquid velocities, and a larger angle of attack all resulted in an increased number of small size bubbles and a reduced weighted mean bubble size. Bubble-water gas transfer is measured by the disturbed equilibrium technique. The gas transfer model of Azbel (1981) is utilized to characterize the liquid film coefficient for gas transfer, with one scaling coefficient to reflect the fact that characteristic turbulent velocity is replaced by cross-sectional mean velocity. The coefficient was found to stay constant at a particular hydrofoil configuration while it varied within a narrow range of 0.52-0.60 for different gas/water flow conditions.

  19. Slug flow transitions in horizontal gas/liquid two-phase flows. Dependence on channel height and system pressure for air/water and steam/water two-phase flows

    International Nuclear Information System (INIS)

    Nakamura, Hideo

    1996-05-01

    The slug flow transitions and related phenomena for horizontal two-phase flows were studied for a better prediction of two-phase flows that typically appear during the reactor loss-of-coolant accidents (LOCAs). For better representation of the flow conditions experimentally, two large-scaled facility: TPTF for high-pressure steam/water two-phase flows and large duct test facility for air/water two-phase flows, were used. The visual observation of the flow using a video-probe was performed in the TPTF experiments for good understanding of the phenomena. The currently-used models and correlations based mostly on the small-scale low-pressure experiments were reviewed and improved based on these experimental results. The modified Taitel-Dukler model for prediction of transition into slug flow from wavy flow and the modified Steen-Wallis correlation for prediction of onset of liquid entrainment from the interfacial waves were obtained. An empirical correlation for the gas-liquid interfacial friction factor was obtained further for prediction of liquid levels at wavy flow. The region of slug flow regime that is generally under influences of the channel height and system pressure was predicted well when these models and correlations were applied together. (author). 90 refs

  20. Trickle/pulse flow regime transition in downflow packed tower involving foaming liquids

    Directory of Open Access Journals (Sweden)

    Sodhi Vijay

    2012-01-01

    Full Text Available The most of past studies in foaming trickle bed reactors aimed at the improvement of efficiency and operational parameters leads to high economic advantages. Conventionally most of the industries rely on frequently used gas continuous flow (GCF where operational output is satisfactory but not yields efficiently as in pulsing flow (PF and foaming pulsing flow (FPF. Hydrodynamic characteristics like regime transitions are significantly influenced by foaming nature of liquid as well as gas and liquid flow rates. This study’s aim was to demonstrate experimentally the effects of liquid flow rate, gas flow rates and liquid surface tension on regime transition. These parameters were analyzed for the air-aqueous Sodium Lauryl Sulphate and air-water systems. More than 240 experiments were done to obtain the transition boundary for trickle flow (GCF to foaming pulsing flow (PF/FPF by use excessive foaming 15-60 ppm surfactant compositions. The trickle to pulse flow transition appeared at lower gas and liquid flow rates with decrease in liquid surface tension. All experimental data had been collected and drawn in the form of four different transitional plots which are compared and drawn by using flow coordinates proposed by different researchers. A prominent decrease in dynamic liquid saturation was observed especially during regime transitional change. The reactor two phase pressure evident a sharp rise to verify the regime transition shift from GCF to PF/FPF. Present study reveals, the regime transition boundary significantly influenced by any change in hydrodynamic as well as physiochemical properties including surface tension.

  1. Determination of Diffusion Coefficients and Activation Energy of Selected Organic Liquids using Reversed-Flow Gas Chromatographic Technique

    International Nuclear Information System (INIS)

    Khalisanni Khalid; Rashid Atta Khan; Sharifuddin Mohd Zain

    2012-01-01

    Evaporation of vaporize organic liquid has ecological consequences when the compounds are introduced into both freshwater and marine environments through industrial effluents, or introduced directly into the air from industrial unit processes such as bioreactors and cooling towers. In such cases, a rapid and simple method are needed to measure physicochemical properties of the organic liquids. The Reversed-Flow Gas Chromatography (RF-GC) sampling technique is an easy, fast and accurate procedure. It was used to measure the diffusion coefficients of vapors from liquid into a carrier gas and at the same time to determine the rate coefficients for the evaporation of the respective liquid. The mathematical expression describing the elution curves of the samples peaks was derived and used to calculate the respective parameters for the selected liquid pollutants selected such as methanol, ethanol, 1-propanol, 1-butanol, n-pentane, n-hexane, n-heptane and n-hexadecane, evaporating into the carrier gas of nitrogen. The values of diffusion coefficients found were compared with those calculated theoretically or reported in the literature. The values of evaporation rate were used to determine the activation energy of respective samples using Arrhenius equation. An interesting finding of this work is by using an alternative mathematical analysis based on equilibrium at the liquid-gas interphase, the comparison leads to profound agreement between theoretical values of diffusion coefficients and experimental evidence. (author)

  2. Empirical Correlations and CFD Simulations of Vertical Two-Phase Gas-Liquid (Newtonian and Non-Newtonian) Slug Flow Compared Against Experimental Data of Void Fraction

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Majumder, S.K.; Bentzen, Thomas Ruby

    2013-01-01

    Gas-Newtonian liquid two-phase flows (TPFs) are presented in several industrial processes (e.g. oil-gas industry). In spite of the common occurrence of these TPFs, the understanding of them is limited compared to single-phase flows. Various studies on TPF focus on developing empirical correlations...... based on large sets of experimental data for void fraction, which have proven accurate for specific conditions for which they were developed limiting their applicability. On the other hand, few studies focus on gas-non-Newtonian liquids TPFs, which are very common in chemical processes. The main reason...... is due to the characterization of the viscosity, which determines the hydraulic regime and flow behaviours of the system. The focus of this study is the analysis of the TPF (slug flow) for Newtonian and non-Newtonian liquids in a vertical pipe in terms of void fraction using computational fluid dynamics...

  3. Flow Rates in Liquid Chromatography, Gas Chromatography and Supercritical Fluid Chromatography: A Tool for Optimization

    Directory of Open Access Journals (Sweden)

    Joris Meurs

    2016-08-01

    Full Text Available This paper aimed to develop a standalone application for optimizing flow rates in liquid chromatography (LC, gas chromatography (GC and supercritical fluid chromatography (SFC. To do so, Van Deemter’s equation, Knox’ equation and Golay’s equation were implemented in a MATLAB script and subsequently a graphical user interface (GUI was created. The application will show the optimal flow rate or linear velocity and the corresponding plate height for the set input parameters. Furthermore, a plot will be shown in which the plate height is plotted against the linear flow velocity. Hence, this application will give optimized flow rates for any set conditions with minimal effort.

  4. Prediction of gas and liquid turbulent mixing rates between rod bundle subchannels in a two-phase slug-churn flow

    International Nuclear Information System (INIS)

    Kawahara, Akimaro; Sadatomi, Michio; Tomino, Takayoshi

    2000-01-01

    This paper presents a slug-churn flow model for predicting turbulent mixing rates of both gas and liquid phases between adjacent subchannels in a BWR fuel rod bundle. In the model, the mixing rate of the liquid phase is calculated as the sum of the three components, i.e., turbulent diffusion, convective transfer and pressure difference fluctuations between the subchannels. The components of turbulent diffusion and convective transfer are calculated from Sadatomi et al.'s (1996) method, applicable to single-phase turbulent mixing, by considering the effect of the increment of liquid velocity due to the presence of gas phase. The component of the pressure difference fluctuations is evaluated from a newly developed correlation. The mixing rate of the gas phase, on the other side, is calculated from a simple relation of mixing rate between gas and liquid phases. The validity of the proposed model has been confirmed with the turbulent mixing rates data of Rudzinski et al. as well as the present authors. (author)

  5. The speed of sound in a gas-vapour bubbly liquid.

    Science.gov (United States)

    Prosperetti, Andrea

    2015-10-06

    In addition to the vapour of the liquid, bubbles in cavitating flows usually contain also a certain amount of permanent gas that diffuses out of the liquid as they grow. This paper presents a simplified linear model for the propagation of monochromatic pressure waves in a bubbly liquid with these characteristics. Phase change effects are included in detail, while the gas is assumed to follow a polytropic law. It is shown that even a small amount of permanent gas can have a major effect on the behaviour of the system. Particular attention is paid to the low-frequency range, which is of special concern in flow cavitation. Numerical results for water and liquid oxygen illustrate the implications of the model.

  6. Heat transfer by liquids in suspension in a turbulent gas stream (1960)

    International Nuclear Information System (INIS)

    Grison, E.; Commissariat a l'Energie Atomique, Saclay

    1960-01-01

    The introduction of a small volume of liquid into a turbulent gas stream used as cooling agent improves considerably the heat transfer coefficient of the gas. When the turbulent regime is established, one observes in a cylindrical tube two types of flow whether the liquid wets or does not wet the wall. In the first case, one gets on the wall an annular liquid film and droplets in suspension are in the gas stream. In the second case, a fog of droplets is formed without any liquid film on the wall. Experiments were performed with the following mixtures: water-hydrogen, water-nitrogen, ethanol-nitrogen (wetting liquids) introduced into a stainless steel tube of 4 mm ID, electrically heated on 320 mm of length. We varied the gas flow rate (Reynolds until 50000), the rate of the liquid flow rate to gas flow rate (until 15), the pressure (until 10 kg/cm 2 ), the temperature (until the boiling point) and the heat flux (until 250 W/cm 2 ). Two types of burnout were observed. A formula of correlation of the burnout heat flux is given. Making use of the analogy between mass transfer and heat transfer, a dimensionless formula of correlation of the local heat transfer coefficients is established. (author) [fr

  7. Identification method for gas-liquid two-phase flow regime based on singular value decomposition and least square support vector machine

    International Nuclear Information System (INIS)

    Sun Bin; Zhou Yunlong; Zhao Peng; Guan Yuebo

    2007-01-01

    Aiming at the non-stationary characteristics of differential pressure fluctuation signals of gas-liquid two-phase flow, and the slow convergence of learning and liability of dropping into local minima for BP neural networks, flow regime identification method based on Singular Value Decomposition (SVD) and Least Square Support Vector Machine (LS-SVM) is presented. First of all, the Empirical Mode Decomposition (EMD) method is used to decompose the differential pressure fluctuation signals of gas-liquid two-phase flow into a number of stationary Intrinsic Mode Functions (IMFs) components from which the initial feature vector matrix is formed. By applying the singular vale decomposition technique to the initial feature vector matrixes, the singular values are obtained. Finally, the singular values serve as the flow regime characteristic vector to be LS-SVM classifier and flow regimes are identified by the output of the classifier. The identification result of four typical flow regimes of air-water two-phase flow in horizontal pipe has shown that this method achieves a higher identification rate. (authors)

  8. A combined CFD-experimental method for developing an erosion equation for both gas-sand and liquid-sand flows

    Science.gov (United States)

    Mansouri, Amir

    The surface degradation of equipment due to consecutive impacts of abrasive particles carried by fluid flow is called solid particle erosion. Solid particle erosion occurs in many industries including oil and gas. In order to prevent abrupt failures and costly repairs, it is essential to predict the erosion rate and identify the locations of the equipment that are mostly at risk. Computational Fluid Dynamics (CFD) is a powerful tool for predicting the erosion rate. Erosion prediction using CFD analysis includes three steps: (1) obtaining flow solution, (2) particle tracking and calculating the particle impact speed and angle, and (3) relating the particle impact information to mass loss of material through an erosion equation. Erosion equations are commonly generated using dry impingement jet tests (sand-air), since the particle impact speed and angle are assumed not to deviate from conditions in the jet. However, in slurry flows, a wide range of particle impact speeds and angles are produced in a single slurry jet test with liquid and sand particles. In this study, a novel and combined CFD/experimental method for developing an erosion equation in slurry flows is presented. In this method, a CFD analysis is used to characterize the particle impact speed, angle, and impact rate at specific locations on the test sample. Then, the particle impact data are related to the measured erosion depth to achieve an erosion equation from submerged testing. Traditionally, it was assumed that the erosion equation developed based on gas testing can be used for both gas-sand and liquid-sand flows. The erosion equations developed in this work were implemented in a CFD code, and CFD predictions were validated for various test conditions. It was shown that the erosion equation developed based on slurry tests can significantly improve the local thickness loss prediction in slurry flows. Finally, a generalized erosion equation is proposed which can be used to predict the erosion rate in

  9. Source modulation-correlation measurement for fissile mass flow in gas or liquid fissile streams

    International Nuclear Information System (INIS)

    Mihalczo, J.T.; March-Leuba, J.A.; Valentine, T.E.; Abston, R.A.; Mattingly, J.K.; Mullens, J.A.

    1996-01-01

    The method of monitoring fissile mass flow on all three legs of a blending point, where the input is high-enriched uranium (HEU) and low-enriched uranium (LEU) and the product is PEU, can yield the fissile stream velocity and, with calibration, the [sup235]U content. The product of velocity and content integrated over the pipe gives the fissile mass flow in each leg. Also, the ratio of fissile contents in each pipe: HEU/LEU, HEU/PEU, and PEU/LEU, are obtained. By modulating the source on the input HEU pipe differently from that on the output pipe, the HEU gas can be tracked through the blend point. This method can be useful for monitoring flow velocity, fissile content, and fissile mass flow in HEU blenddown of UF[sub 6] if the pressures are high enough to contain some of the induced fission products. This method can also be used to monitor transfer of fissile liquids and other gases and liquids that emit radiation delayed from particle capture. These preliminary experiments with the Oak Ridge apparatus show that the method will work and the modeling is adequate

  10. Derivation of simplified basic equations of gas-liquid two-phase dispersed flow based on two-fluid model

    International Nuclear Information System (INIS)

    Kataoka, Isao; Tomiyama, Akio

    2004-01-01

    The simplified and physically reasonable basic equations for the gas-liquid dispersed flow were developed based on some appropriate assumptions and the treatment of dispersed phase as isothermal rigid particles. Based on the local instant formulation of mass, momentum and energy conservation of the dispersed flow, time-averaged equations were obtained assuming that physical quantities in the dispersed phase are uniform. These assumptions are approximately valid when phase change rate and/or chemical reaction rate are not so large at gas-liquid interface and there is no heat generation in within the dispersed phase. Detailed discussions were made on the characteristics of obtained basic equations and physical meanings of terms consisting the basic equations. It is shown that, in the derived averaged momentum equation, the terms of pressure gradient and viscous momentum diffusion do not appear and, in the energy equation, the term of molecular thermal diffusion heat flux does not appear. These characteristics of the derived equations were shown to be very consistent concerning the physical interpretation of the gas-liquid dispersed flow. Furthermore, the obtained basic equations are consistent with experiments for the dispersed flow where most of averaged physical quantities are obtained assuming that the distributions of those are uniform within the dispersed phase. Investigation was made on the problem whether the obtained basic equations are well-posed or ill-posed for the initial value problem. The eigenvalues of the simplified mass and momentum equations are calculated for basic equations obtained here and previous two-fluid basic equations with one pressure model. Well-posedness and ill-posedness are judged whether the eigenvalues are real or imaginary. The result indicated the newly developed basic equations always constitute the well-posed initial value problem while the previous two-fluid basic equations based on one pressure model constitutes ill

  11. Two-phase heat and mass transfer in turbulent parallel and countercurrent flows of liquid film and gas

    International Nuclear Information System (INIS)

    Kholpanov, L.P.; Babak, T.B.; Babak, V.N.; Malyusov, V.A.; Zhavoronkov, N.M.; AN SSSR, Moscow. Inst. Obshchej i Neorganicheskoj Khimii)

    1980-01-01

    To determine the ways of intensification of heat and mass transfer processes, the direct flow and counterflow heat and mass transfer is analytically investigated during the turbulent flow of a liquid and gas film on the basis of solving the energy equation for liquid and gas film, i.e. the two-phase film heat transfer is investigated from the position of a conjugate task. The analysis of the two-phase heat transfer has shown that it is necessary to know the position of each point in a plane before using this or that formula. Depending on its position on this plane, the heat transfer process will be determined by one or two phases only. It is found, that in the case of a single-phase heat transfer the temperature on the surface remains stable over the channel length. In the case of a two-phase heat transfer it can significantly change over the channel length [ru

  12. Numerical simulation of liquid droplet breakup in supersonic flows

    Science.gov (United States)

    Liu, Nan; Wang, Zhenguo; Sun, Mingbo; Wang, Hongbo; Wang, Bing

    2018-04-01

    A five-equation model based on finite-difference frame was utilized to simulate liquid droplet breakup in supersonic flows. To enhance the interface-capturing quality, an anti-diffusion method was introduced as a correction of volume-fraction after each step of calculation to sharpen the interface. The robustness was guaranteed by the hybrid variable reconstruction in which the second-order and high-order method were respectively employed in discontinuous and continuous flow fields. According to the recent classification of droplet breakup regimes, the simulations lay in the shear induced entrainment regime. Comparing to the momentum of the high-speed air flows, surface tension and viscid force were negligible in both two-dimensional and three-dimensional simulations. The inflow conditions were set as Mach 1.2, 1.5 and 1.8 to reach different dynamic pressure with the liquid to gas density ratio being 1000 initially. According to the results of simulations, the breakup process was divided into three stages which were analyzed in details with the consideration of interactions between gas and liquid. The shear between the high-speed gas flow and the liquid droplet was found to be the sources of surface instabilities on windward, while the instabilities on the leeward side were originated by vortices. Movement of the liquid mass center was studied, and the unsteady acceleration was observed. In addition, the characteristic breakup time was around 1.0 based on the criterion of either droplet thickness or liquid volume fraction.

  13. Discharge characteristics and hydrodynamics behaviors of atmospheric plasma jets produced in various gas flow patterns

    Science.gov (United States)

    Setsuhara, Yuichi; Uchida, Giichiro; Nakajima, Atsushi; Takenaka, Kosuke; Koga, Kazunori; Shiratani, Masaharu

    2015-09-01

    Atmospheric nonequilibrium plasma jets have been widely employed in biomedical applications. For biomedical applications, it is an important issue to understand the complicated mechanism of interaction of the plasma jet with liquid. In this study, we present analysis of the discharge characteristics of a plasma jet impinging onto the liquid surface under various gas flow patterns such as laminar and turbulence flows. For this purpose, we analyzed gas flow patters by using a Schlieren gas-flow imaging system in detail The plasma jet impinging into the liquid surface expands along the liquid surface. The diameter of the expanded plasma increases with gas flow rate, which is well explained by an increase in the diameter of the laminar gas-flow channel. When the gas flow rate is further increased, the gas flow mode transits from laminar to turbulence in the gas flow channel, which leads to the shortening of the plasm-jet length. Our experiment demonstrated that the gas flow patterns strongly affect the discharge characteristics in the plasma-jet system. This study was partly supported by a Grant-in-Aid for Scientific Research on Innovative Areas ``Plasma Medical Innovation'' (24108003) from the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT).

  14. Theoretical Study on the Dynamic Behavior of Pipes Conveying Gas-Liquid Flow

    Directory of Open Access Journals (Sweden)

    Enrique Ortiz-Vidal L.

    2018-01-01

    Full Text Available The dynamic behavior of clamped-clamped straight pipes conveying gas-liquid two-phase flow is theoretically investigated, specifically the effect of the flow parameters on the frequency of the system. First, the equation of motion is derived based on the classic Païdoussis formulation. Assuming Euler-Bernoulli beam theory, small-deflection approximation and no-slip homogeneous model, a coupled fluid-structure fourth-order partial differential equation (PDE is obtained. Then, the equation of motion is rendered dimensionless and discretized through Galerkin’s method. That method transforms the PDE into a set of Ordinary Differential Equations (ODEs. The system frequency is obtained by solving the system of ODEs by allowing the determinant to be equal to zero. System frequencies for different geometries, structural properties and flow conditions have been calculated. The results show that the system frequency decreases with increasing two-phase flow velocity. By contrast, the former increases with increasing homogeneous void fraction. These theoretical results are in agreement with experimental findings reported in the literature. Furthermore, even for typical two phase flow conditions, the system can become unstable for inadequate chooses of geometry or material of the pipe.

  15. Bubble Generation in a Flowing Liquid Medium and Resulting Two-Phase Flow in Microgravity

    Science.gov (United States)

    Pais, S. C.; Kamotani, Y.; Bhunia, A.; Ostrach, S.

    1999-01-01

    The present investigation reports a study of bubble generation under reduced gravity conditions, using both a co-flow and a cross-flow configuration. This study may be used in the conceptual design of a space-based thermal management system. Ensuing two-phase flow void fraction can be accurately monitored using a single nozzle gas injection system within a continuous liquid flow conduit, as utilized in the present investigation. Accurate monitoring of void fraction leads to precise control of heat and mass transfer coefficients related to a thermal management system; hence providing an efficient and highly effective means of removing heat aboard spacecraft or space stations. Our experiments are performed in parabolic flight aboard the modified DC-9 Reduced Gravity Research Aircraft at NASA Lewis Research Center, using an air-water system. For the purpose of bubble dispersion in a flowing liquid, we use both a co-flow and a cross-flow configuration. In the co-flow geometry, air is introduced through a nozzle in the same direction with the liquid flow. On the other hand, in the cross-flow configuration, air is injected perpendicular to the direction of water flow, via a nozzle protruding inside the two-phase flow conduit. Three different flow conduit (pipe) diameters are used, namely, 1.27 cm, 1.9 cm and 2.54 cm. Two different ratios of nozzle to pipe diameter (D(sub N))sup * are considered, namely (D(sub N))sup * = 0.1 and 0.2, while superficial liquid velocities are varied from 8 to 70 cm/s depending on flow conduit diameter. It is experimentally observed that by holding all other flow conditions and geometry constant, generated bubbles decrease in size with increase in superficial liquid velocity. Detached bubble diameter is shown to increase with air injection nozzle diameter. Likewise, generated bubbles grow in size with increasing pipe diameter. Along the same lines, it is shown that bubble frequency of formation increases and hence the time to detachment of a

  16. Characterisation of Liquid Slugs in Gas-Liquid Taylor Flow in Microchannels

    Czech Academy of Sciences Publication Activity Database

    Záloha, Petr; Křišťál, Jiří; Jiřičný, Vladimír; Völkel, N.; Xuereb, C.; Aubin, J.

    2012-01-01

    Roč. 68, č. 1 (2012), s. 640-649 ISSN 0009-2509 Grant - others:IMPULSE(XE) NMP2-CT-2005-011816 Institutional research plan: CEZ:AV0Z40720504 Keywords : gas-liquid * micro-piv * microreactor Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.386, year: 2012

  17. Dryout characteristics and flow behavior of gas-water two-phase flow through U-shaped and inverted U-shaped bends

    International Nuclear Information System (INIS)

    Takemura, T.; Roko, K.; Shiraha, M.; Midoriyama, S.

    1986-01-01

    Experimental results are presented on the flow behavior, pressure drop characteristics, and dryout characteristics by joule heating for the gas-water flow through U-shaped and inverted U-shaped tubes invertical plane. The height of the vertical straight section of the test tube is 4100 mm, and two bend radii, 116 mm and 435 mm, are chosen for the experiments. The test tubes used are of transparent acrylic resin for the flow behavior test, and of stainless steel for the other tests, inside diameter being 18 mm for the former and 18.5 mm for the latter. Flow patterns in the vertical upflow and downflow sections are shown on the diagram of the superficial gas velocity versus liquid velocity. Further, the flow behavior in the bend section is made clear in relation to flow rates of gas and liquid. The pressure drop between inlet and outlet of the test tube for the made clear in relation to flow rates of gas and liquid. The pressure drop between inlet and outlet of the test tube for the two-phase flow is shown in comparison with that for the single-phase flow of water. The threshold conditions of dryout in the bend section by joule heatig are shown on the diagram of the superficial gas velocity versus liquid velocity. The location of the dryout in the bend section is also clarified. (orig.)

  18. Evolution of the structure of a gas-liquid two-phase flow in a large vertical pipe

    International Nuclear Information System (INIS)

    Horst-Michael Prasser; Matthias Beyer; Helmar Carl; Sabine Gregor; Dirk Lucas; Peter Schuetz; Frank-Peter Weiss

    2005-01-01

    Full text of publication follows: Experimental results on the evolution of the radial gas fraction profiles, gas velocity profiles and bubble size distributions in a gas-liquid two-phase flow along a large vertical pipe of 194 mm inner diameter are presented. The tests were performed at the TOPFLOW facility in Rossendorf, where two wire-mesh sensors were used to measure sequences of two-dimensional distributions of local instantaneous gas fraction within the complete pipe cross-section with a lateral resolution of 3 mm and a sampling frequency of 2500 Hz. This data is the basis for a fast flow visualization and for the calculation of the mentioned profiles. The gas fraction profiles were obtained by averaging the sequences over time, velocities were measured by cross-correlation of the signals of the two sensors, which were located on a short (63 mm) distance behind each other. The high resolution of the mesh sensors allows to identify regions of connected measuring points in the data array, which are filled with the gas phase. This method was used to obtain the bubble size distributions. In the experiments, the superficial velocities ranged from 0.04 to 8 m/s for the gas phase and from 0.04 to 1.6 m/s for the liquid. In this way, the experiments cover the range from bubbly to churn turbulent flow regimes. The evolution of the flow structure was studied by varying the distance between the gas injection and the sensor position. This distance was changed by the help of a so-called variable gas injection set-up. It consists of 6 gas injection units, each of them equipped with three rings of orifices in the pipe wall for the gas injection. These rings are fed with the gas phase from ring chambers, which can be individually controlled by valves. The middle ring has orifices of 4 mm diameter, while the upper and the lower rings have nozzles of 1 mm diameter. In this way, 18 different inlet lengths and two different gas injection geometries can be chosen. The latter

  19. Long liquid slugs in stratified gas/liquid flow in horizontal and slightly inclined pipes

    NARCIS (Netherlands)

    Kadri, U.

    2009-01-01

    Long liquid slugs reaching several hundreds pipe diameter may appear when transporting gas and liquid in horizontal and near horizontal pipes. The long slugs cause system vibration and separation difficulties that may lead to operational failures. Identifying and predicting the time and length

  20. Prediction of turbulent mixing rates of both gas and liquid phases between adjacent subchannels in a two-phase slug-churn flow

    International Nuclear Information System (INIS)

    Kawahara, A.; Sadatomi, M.; Tomino, T.; Sato, Y.

    1998-01-01

    This paper presents a slug-churn flow model for predicting turbulent mixing rates of both gas and liquid phase between adjacent subchannels in a BWR fuel rod bundle. In the model, the mixing rate of the liquid phase is calculated as the sum of the three components, i.e., turbulent diffusion, convective transfer and pressure difference fluctuations between the subchannels. The compenents of turbulent diffusion and convective transfer are calculated from Sadatomi et al.'s (1996) method, applicable to single-phase turbulent mixing by considering the effect of the increment of liquid velocity due to the presence of gas phase. The component of the pressure difference fluctuations is evaluated from a newly developed correlations. The mixing rate of the gas phase, on the other side, is calculated from a simple relation of mixing rate between gas and liquid phases. The validity of the proposed model has been confirmed with the turbulent mixing rates data of Rudzinski et al. as well as the present authors

  1. Lessons from wet gas flow metering systems using differential measurements devices: Testing and flow modelling results

    Energy Technology Data Exchange (ETDEWEB)

    Cazin, J.; Couput, J.P.; Dudezert, C. et al

    2005-07-01

    A significant number of wet gas meters used for high GVF and very high GVF are based on differential pressure measurements. Recent high pressure tests performed on a variety of different DP devices on different flow loops are presented. Application of existing correlations is discussed for several DP devices including Venturi meters. For Venturi meters, deviations vary from 9% when using the Murdock correlation to less than 3 % with physical based models. The use of DP system in a large domain of conditions (Water Liquid Ratio) especially for liquid estimation will require information on the WLR This obviously raises the question of the gas and liquid flow metering accuracy in wet gas meters and highlight needs to understand AP systems behaviour in wet gas flows (annular / mist / annular mist). As an example, experimental results obtained on the influence of liquid film characteristics on a Venturi meter are presented. Visualizations of the film upstream and inside the Venturi meter are shown. They are completed by film characterization. The AP measurements indicate that for a same Lockhart Martinelli parameter, the characteristics of the two phase flow have a major influence on the correlation coefficient. A 1D model is defined and the results are compared with the experiments. These results indicate that the flow regime influences the AP measurements and that a better modelling of the flow phenomena is needed even for allocation purposes. Based on that, lessons and way forward in wet gas metering systems improvement for allocation and well metering are discussed and proposed. (author) (tk)

  2. New perspective on gas-well liquid loading and unloading

    NARCIS (Netherlands)

    Veeken, C.A.M.; Belfroid, S.P.C.

    2010-01-01

    This paper discusses the multiphase flow mechanism responsible for gas-well liquid loading. It shows that the conventional idea of droplet flow reversal (Turner et al. (1969)) does not capture reality and that actual observations are better described by film flow reversal. This paper subsequently

  3. Investigation and visualization of liquid-liquid flow in a vertically mounted Hele-Shaw cell: flow regimes, velocity and shape of droplets

    Science.gov (United States)

    Shad, S.; Gates, I. D.; Maini, B. B.

    2009-11-01

    The motion and shape of a liquid drop flowing within a continuous, conveying liquid phase in a vertical Hele-Shaw cell were investigated experimentally. The continuous phase was more viscous and wetted the bounding walls of the Hele-Shaw cell. The gap between the Hele-Shaw plates was set equal to 0.0226 cm. Four different flow regimes were observed: (a) small-droplet flow, (b) elongated-droplet flow, (c) churn flow and (d) channel flow. At low capillary number, that is, when capillary forces are larger than viscous forces, the droplet shape was irregular and changed with time and distance, and it moved with lower velocity than that of the conveying phase. At higher capillary number, several different shapes of stabilized elongated and flattened drops were observed. In contrast to gas-liquid systems, the velocities of droplets are higher than that of conveying liquid. New correlations derived from dimensionless analysis and fitted to the experimental data were generated to predict the elongated-drop velocity and aspect ratio.

  4. An analysis of the falling film gas-liquid reactor

    NARCIS (Netherlands)

    Davis, E.J.; Ouwerkerk-Dijkers, van M.P.; Venkatesh, S.

    1979-01-01

    A mathematical model of the falling film reactor is developed to predict the conversion and temperature distribution in the reactor as a function of the gas and liquid flow rates, physical properties, the feed composition of the reactive gas and carrier gas and other parameters of the system.

  5. Validation of ANSYS CFX for gas and liquid metal flows with conjugate heat transfer within the European project THINS

    Energy Technology Data Exchange (ETDEWEB)

    Papukchiev, A., E-mail: angel.papukchiev@grs.de; Buchholz, S.

    2017-02-15

    Highlights: • ANSYS CFX is validated for gas and liquid metal flows. • L-STAR and TALL-3D experiments are simulated. • Complex flow and heat transfer phenomena are modelled. • Conjugate heat transfer has to be considered in CFD analyses. - Abstract: Within the FP7 European project THINS (Thermal Hydraulics of Innovative Nuclear Systems), numerical tools for the simulation of the thermal-hydraulics of next generation rector systems were developed, applied and validated for innovative coolants. The Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH participated in THINS with activities related to the development and validation of computational fluid dynamics (CFD) and coupled System Thermal Hydraulics (STH) – CFD codes. High quality measurements from the L-STAR and TALL-3D experiments were used to assess the numerical results. Two-equation eddy viscosity and scale resolving turbulence models were used in the validation process of ANSYS CFX for gas and liquid metal flows with conjugate heat transfer. This paper provides a brief overview on the main results achieved at GRS within the project.

  6. Empirical Correlations and CFD Simulations of Vertical Two-Phase Gas-Liquid (Newtonian and Non-Newtonian) Flow Compared Against Experimental Data of Void Fraction and Pressure Drop

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Bentzen, Thomas Ruby; Majumder, S.K.

    2012-01-01

    Gas-Newtonian liquid two-phase flows (TPFs) are presented in several industrial processes (i.e. oil-gas industry). In spite of the common occurrence of these TPFs, their understanding is limited compared to single-phase flows. Different studies on TPF have focus on developing empirical correlations...... based in large sets of experiment data for void fraction and pressure drop which have proven to be accurate for specific condition that their where developed for, which limit their applicability. On the other hand, scarce studies focus on gas-non-Newtonian liquids TPFs, which are very common in chemical...... processes. The main reason for it is due to the characterization of the viscosity, which determines the hydraulic regime and flow behaviours on the system. The focus of this study is the analysis of the TPF for Newtonian and non-Newtonian liquids in a vertical pipe in terms of void fraction and total...

  7. Automatic discrimination of bubbles and slugs in two-phase gas-liquid flow and measurement of the respective velocities

    International Nuclear Information System (INIS)

    Fitremann, J.M.; Guilpin, C.; Postaire, J.

    1976-01-01

    The measurement of the interface velocity in a two-phase gas-liquid flow is a difficult problem, owing to the dispersion of the velocity components of individual bubbles, gas-slugs, droplets, waves, etc. An entirely automatic method is presented, it gives the velocity of slugs and bubbles independently, by discrimination of local phase probe signals into a 'slug' signal and a 'bubble' signal feeding a shape-recognition program. Both discriminated void fractions are also calculated by the apparatus [fr

  8. Measurement of turbulent diffusivity of both gas and liquid phases in quasi-2D two-phase flow

    International Nuclear Information System (INIS)

    Sato, Yoshifusa; Sadatomi, Michio; Kawahara, Akimaro

    1993-01-01

    The turbulent diffusion process has been studied experimentally by observing a tracer plume emitted continuously from a line source in a uniform, quasi-2D two-phase flow. The test section was a vertical, relatively narrow, concentric annular channel consisting of two large pipes. Air and water were used as the working fluids, and methane and acid organge II were used as tracers for the respective phases. Measurements of local, time-averaged tracer concentrations were made by means of a sampling method and image processing for bubbly flows and churn flows, and the turbulent diffusivity, the coefficient of turbulent diffusion, was determined from the concentration distributions measured. The diffusivities for the gas and liquid phases, ε DG and ε DL respectively, are presented and compared with each other in this paper. When a flow is bubbly, ε DG is close to or slightly smaller than ε DL . In a churn flow, on the contrary, ε DG is much greater than ε DL . Regarding bubbly flow, a plausible model on turbulent diffusivity of the liquid phase is presented and examined by the present data. (orig.)

  9. Analysis of a gas-liquid film plasma reactor for organic compound oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Kevin [Department of Chemical and Biomedical Engineering, Florida State University, Tallahassee, FL 32310 (United States); Wang, Huijuan [School of Environmental and Safety Engineering, Jiangsu University, Zhenjiang 212013 (China); Locke, Bruce R., E-mail: blocke@fsu.edu [Department of Chemical and Biomedical Engineering, Florida State University, Tallahassee, FL 32310 (United States)

    2016-11-05

    Highlights: • Non-homogeneous filamentary plasma discharge formed along gas-liquid interface. • Hydrogen peroxide formed near interface favored over organic oxidation from liquid. • Post-plasma Fenton reactions lead to complete utilization of hydrogen peroxide. - Abstract: A pulsed electrical discharge plasma formed in a tubular reactor with flowing argon carrier gas and a liquid water film was analyzed using methylene blue as a liquid phase hydroxyl radical scavenger and simultaneous measurements of hydrogen peroxide formation. The effects of liquid flow rate, liquid conductivity, concentration of dye, and the addition of ferrous ion on dye decoloration and degradation were determined. Higher liquid flow rates and concentrations of dye resulted in less decoloration percentages and hydrogen peroxide formation due to initial liquid conductivity effects and lower residence times in the reactor. The highest decoloration energy yield of dye found in these studies was 5.2 g/kWh when using the higher liquid flow rate and adding the catalyst. The non-homogeneous nature of the plasma discharge favors the production of hydrogen peroxide in the plasma-liquid interface over the chemical oxidation of the organic in the bulk liquid phase and post-plasma reactions with the Fenton catalyst lead to complete utilization of the plasma-formed hydrogen peroxide.

  10. Dynamic simulation of gas-liquid two-phase flow : effect of column aspect ratio on the flow structure

    NARCIS (Netherlands)

    Delnoij, E.; Kuipers, J.A.M.; van Swaaij, W.P.M.

    1997-01-01

    In this paper an Eulerian/Lagrangian model, describing the hydrodynamics of a gas-liquid bubble column, is presented. The model resolves the time dependent, two-dimensional motion of small, spherical gas bubbles in a liquid using the equation of motion. The model incorporates all relevant forces

  11. Dynamic simulation of gas-liquid two-phase flow: effect of column aspect ratio on the flow structure.

    NARCIS (Netherlands)

    Delnoij, E.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

    1997-01-01

    In this paper an Eulerian/Lagrangian model, describing the hydrodynamics of a gas-liquid bubble column, is presented. The model resolves the time dependent, two-dimensional motion of small, spherical gas bubbles in a liquid using the equation of motion. The model incorporates all relevant forces

  12. Comparison of various droplet breakup models in gas-liquid flows in high-pressure environments

    International Nuclear Information System (INIS)

    Khaleghi, H.; Ganji, D. D.; Omidvar, A.

    2008-01-01

    Droplet breakup affects spray penetration and evaporation, and plays a critical role in engine efficiency. The purpose of this research was to examine the rate of penetration and evaporation of droplets in a combustion chamber, and the efficiency of the engine when liquid jet is injected into the compressed gas chamber in an axi-symmetrical fashion leading to a turbulent and unsteady flow. As a result of interaction with the highly compressed air in the chamber, the liquid jet breaks up and forms minute droplets. These particles will in turn breakup because of aerodynamic forces, producing even smaller droplets. A number of models are available for analyzing the breakup of droplets; however, each model is typically reliable only over a limited parameter range. In this research three well-known models are applied for droplet breakup modeling and their results are compared. To obtain the details of the flow field, the Eulerian gas phase mass, momentum and energy conservation equations, as well as equations governing the transport of turbulence and fuel vapor mass fraction are solved together with equations of trajectory, momentum, mass and energy conservation for liquid droplets in Lagrangian form. The numerical solution is performed using the finite volume method and EPISO (Engine-PISO) algorithm. The results obtained from the models show that the breakup process in a high pressure environment significantly affects the penetration and evaporation rates of the spray, and the droplet size is determined by the balance between breakup and coalescence processes. It is also shown that the details of atomization in the nozzle do not significantly influence the ultimate size of droplets. It should be mentioned that droplet collision modeling has been taken into account in the computer code and is activated wherever necessary

  13. Study on gas-liquid loop reactors with annular bubbling

    International Nuclear Information System (INIS)

    Fei, L.M.; Wang, S.X.; Wu, X.Q.; Lu, D.W.

    1987-01-01

    Bubbling column with draft tube is one of nearly developed reactor. On the background of hydrocarbon oxidations and biochemical engineerings, it has been widely used in chemical industry due to the well characteristics of mass and heat transfer. In this paper, the characteristics of fluid flow, such as gas hold-up, backmixing and mass transfer referred to the liquid volume were measured in a gas-liquid loop reactor with annular bubbling. Different materials - water, alcohol and oi l- were used in the study in measuring the gas hold-up in the annular of the reactor

  14. Influence of Gas-Liquid Interface on Temperature Wave of Pulsating Heat Pipe

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2018-01-01

    Full Text Available The influence of the interface on the amplitude and phase of the temperature wave and the relationship between the attenuation of the temperature wave and the gas-liquid two-phase physical parameters are studied during the operation of the pulsating heat pipe. The numerical simulation shows that the existence of the phase interface changes the direction of the temperature gradient during the propagation of the temperature wave, which increases the additional “thermal resistance.” The relative size of the gas-liquid two-phase thermal conductivity affects the propagation direction of heat flow at phase interface directly. The blockage of the gas plug causes hysteresis in the phase of the temperature wave, the relative size of the gas-liquid two-phase temperature coefficient will gradually increase the phase of the temperature wave, and the time when the heat flow reaches the peak value is also advanced. The attenuation of the temperature wave is almost irrelevant to the absolute value of the density, heat capacity, and thermal conductivity of the gas-liquid two phases, and the ratio of the thermal conductivity of the gas-liquid two phases is related. When the temperature of the heat pipe was changed, the difference of heat storage ability between gas and liquid will lead to the phenomenon of heat reflux and becomes more pronounced with the increases of the temperature wave.

  15. Wire-mesh and ultrasound techniques applied for the characterization of gas-liquid slug flow

    Energy Technology Data Exchange (ETDEWEB)

    Ofuchi, Cesar Y.; Sieczkowski, Wytila Chagas; Neves Junior, Flavio; Arruda, Lucia V.R.; Morales, Rigoberto E.M.; Amaral, Carlos E.F.; Silva, Marco J. da [Federal University of Technology of Parana, Curitiba, PR (Brazil)], e-mails: ofuchi@utfpr.edu.br, wytila@utfpr.edu.br, neves@utfpr.edu.br, lvrarruda@utfpr.edu.br, rmorales@utfpr.edu.br, camaral@utfpr.edu.br, mdasilva@utfpr.edu.br

    2010-07-01

    Gas-liquid two-phase flows are found in a broad range of industrial applications, such as chemical, petrochemical and nuclear industries and quite often determine the efficiency and safety of process and plants. Several experimental techniques have been proposed and applied to measure and quantify two-phase flows so far. In this experimental study the wire-mesh sensor and an ultrasound technique are used and comparatively evaluated to study two-phase slug flows in horizontal pipes. The wire-mesh is an imaging technique and thus appropriated for scientific studies while ultrasound-based technique is robust and non-intrusive and hence well suited for industrial applications. Based on the measured raw data it is possible to extract some specific slug flow parameters of interest such as mean void fraction and characteristic frequency. The experiments were performed in the Thermal Sciences Laboratory (LACIT) at UTFPR, Brazil, in which an experimental two-phase flow loop is available. The experimental flow loop comprises a horizontal acrylic pipe of 26 mm diameter and 9 m length. Water and air were used to produce the two phase flow under controlled conditions. The results show good agreement between the techniques. (author)

  16. Liquid Natural Gas

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    After a brief introduction on the origins of the Liquid Natural Gas (LNG) industry the production and transportation of LNG are discussed. Special attention is paid to the importance of the safety aspect during every activity or handling of LNG. Next the most important trade flows for LNG are dealt with. Two zones can be distinguished: the western part of the Pacific and the Atlantic basin. Subsequently the main aspects of a LNG-project are mentioned, as well as the success factors. Finally the prospects for the LNG-industry are reviewed. 11 figs

  17. A multiphase flow meter for the on-line determination of the flow rates of oil, water and gas

    International Nuclear Information System (INIS)

    Roach, G.J.; Watt, J.S.

    1997-01-01

    Multiphase mixtures of crude oil, formation water and gas are carried in pipelines from oil wells to production facilities. Multiphase flow meters (MFMs) are being developed to determine the flow rates of each component of the heterogeneous mixture in the pipeline. CSIRO Minerals has developed and field tested a gamma-ray MFM for the on-line determination of the flow rates of heterogeneous mixtures of oil, water and gas in pipelines. It consists of two specialised gamma-ray transmission gauges, and pressure and temperature sensors, mounted on the pipeline carrying the full flow of the production stream. The MFM separately measures liquids and gas flow rates, and the volume ratio of water and liquids (water cut). The MFM has been trialled at three offshore production facilities in Australia. In each, the MFM was mounted on the pipeline between the test manifold and the test separator. The multiphase streams from the various wells feeding to the platform were sequentially routed past the MFM. The MFM and test separator outputs were compared using regression analysis. The flow rates of oil, water and gas were each determined to relative errors in the range of 5-10% . The MFM has been in routine use on the West Kingfish platform in the Bass Strait since November 1994. The MFM was recently tested over a wide range of flow conditions at a Texaco flow facility near Houston. Water cut, based on pre-trial calibration, was determined to 2% rms over the range 0-100% water cut. The liquids and gas flow results were interpreted based on slip correlations obtained from comparison of the MFM and Texaco flows. Using these, the relative errors were respectively 6.6% for liquid flow, 6.2% for gas, 8% for oil and 8% for water. The MFM is licensed to Kvaerner FSSL of Aberdeen. Kvaerner will supply the gamma-ray MFM for both platform and subsea use. Technology transfer commenced in December 1996, and Kvaerner completed the manufacture of the first MFM in August 1997

  18. Unconventional Liquid Flow in Low-Permeability Media: Theory and Revisiting Darcy's Law

    Science.gov (United States)

    Liu, H. H.; Chen, J.

    2017-12-01

    About 80% of fracturing fluid remains in shale formations after hydraulic fracturing and the flow back process. It is critical to understand and accurately model the flow process of fracturing fluids in a shale formation, because the flow has many practical applications for shale gas recovery. Owing to the strong solid-liquid interaction in low-permeability media, Darcy's law is not always adequate for describing liquid flow process in a shale formation. This non-Darcy flow behavior (characterized by nonlinearity of the relationship between liquid flux and hydraulic gradient), however, has not been given enough attention in the shale gas community. The current study develops a systematic methodology to address this important issue. We developed a phenomenological model for liquid flow in shale (in which liquid flux is a power function of pressure gradient), an extension of the conventional Darcy's law, and also a methodology to estimate parameters for the phenomenological model from spontaneous imbibition tests. The validity of our new developments is verified by satisfactory comparisons of theoretical results and observations from our and other research groups. The relative importance of this non-Darcy liquid flow for hydrocarbon production in unconventional reservoirs remains an issue that needs to be further investigated.

  19. Influence of gas-liquid two-phase flow on angiotensin-I converting enzyme inhibitory peptides separation by ultra-filtration.

    Science.gov (United States)

    Charoenphun, Narin; Youravong, Wirote

    2017-01-01

    Membrane fouling is a major problem in ultra-filtration systems and two-phase flow is a promising technique for permeate flux enhancement. The objective of this research was to study the use of an ultra-filtration (UF) system to enrich angiotensin-I converting enzyme (ACE) inhibitory peptides from tilapia protein hydrolysate. To select the most appropriate membrane and operating condition, the effects of membrane molecular weight cut-off (MWCO), transmembrane pressure (TMP) and cross-flow velocity (CFV) on permeate flux and ACE inhibitory peptide separation were studied. Additionally, the gas-liquid two-phase flow technique was applied to investigate its effect on the process capability. The results showed that the highest ACE inhibitory activity was obtained from permeate of the 1 kDa membrane. In terms of TMP and CFV, the permeate flux tended to increase with TMP and CFV. The use of gas-liquid two-phase flow as indicated by shear stress number could reduce membrane fouling and increase the permeate flux up to 42%, depending on shear stress number. Moreover, the use of a shear stress number of 0.039 led to an augmentation in ACE inhibitory activity of permeates. Operating conditions using a shear stress number of 0.039 were recommended for enrichment of ACE inhibitory peptides. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  20. Summary on experimental methods for statistical transient analysis of two-phase gas-liquid flow. [BWR, PWR, and LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Delhaye, J M; Jones, Jr, O C

    1976-06-01

    Much work has been done in the study of two-phase gas-liquid flows. Although it has been recognized superficially that such flows are not homogeneous in general, little attention has been paid to the inherent discreteness of the two-phase systems. Only relatively recently have fluctuating characteristics of two-phase flows been studied in detail. As a result, new experimental devices and techniques have been developed for use in measuring quantities previously ignored. This report reviews and summarizes most of these methods in an effort to emphasize the importance of the fluctuating nature of these flows and as a guide to further research in this field.

  1. Numerical Study of Particle Interaction in Gas-Particle and Liquid-Particle Flows: Part II Particle Response

    Directory of Open Access Journals (Sweden)

    K. Mohanarangam

    2009-09-01

    Full Text Available In this paper the numerical model, which was presented in the first paper (Mohanarangam & Tu; 2009 of this series of study, is employed to study the different particle responses under the influence of two carrier phases namely the gas and the liquid. The numerical model takes into consideration the turbulent behaviour of both the carrier and the dispersed phases, with additional equations to take into account the combined fluid particle behaviour, thereby effecting a two-way coupling. The first paper in this series showed the distinct difference in particulate response both at the mean as well as at the turbulent level for two varied carrier phases. In this paper further investigation has been carried out over a broad range of particle Stokes number to further understand their behaviour in turbulent environments. In order to carry out this prognostic study, the backward facing step geometry of Fessler and Eaton (1999 has been adopted, while the inlet conditions for the carrier as well as the particle phases correspond to that of the experiments of Founti and Klipfel (1998. It is observed that at the mean velocity level the particulate velocities increased with a subsequent increase in the Stokes number for both the GP (Gas-Particle as well as the LP (Liquid-Particle flow. It was also observed that across the Stokes number there was a steady increase in the particulate turbulence for the GP flows with successive increase in Stokes number. However, for the LP flows, the magnitude of the increase in the particulate turbulence across the increasing of Stokes number is not as characteristic as the GP flow. Across the same sections for LP flows the majority of the trend shows a decrease after which they remain more or less a constant.

  2. Using artificial intelligence to improve identification of nanofluid gas–liquid two-phase flow pattern in mini-channel

    Directory of Open Access Journals (Sweden)

    Jian Xiao

    2018-01-01

    Full Text Available This work combines fuzzy logic and a support vector machine (SVM with a principal component analysis (PCA to create an artificial-intelligence system that identifies nanofluid gas-liquid two-phase flow states in a vertical mini-channel. Flow-pattern recognition requires finding the operational details of the process and doing computer simulations and image processing can be used to automate the description of flow patterns in nanofluid gas-liquid two-phase flow. This work uses fuzzy logic and a SVM with PCA to improve the accuracy with which the flow pattern of a nanofluid gas-liquid two-phase flow is identified. To acquire images of nanofluid gas-liquid two-phase flow patterns of flow boiling, a high-speed digital camera was used to record four different types of flow-pattern images, namely annular flow, bubbly flow, churn flow, and slug flow. The textural features extracted by processing the images of nanofluid gas–liquid two-phase flow patterns are used as inputs to various identification schemes such as fuzzy logic, SVM, and SVM with PCA to identify the type of flow pattern. The results indicate that the SVM with reduced characteristics of PCA provides the best identification accuracy and requires less calculation time than the other two schemes. The data reported herein should be very useful for the design and operation of industrial applications.

  3. Multi-dimensional modeling of gas-liquid two-phase flows. Application to the simulation of ascending bubble flows in vertical ducts

    International Nuclear Information System (INIS)

    Morel, Ch.

    1997-01-01

    The aim of this thesis is the 3-D modeling and numerical simulation of liquid/gas (water/vapor or water/air) two-phase flows in cooling circuits of nuclear power plants during normal and accidental situations. The development of a multidimensional dual-fluid model encounters two problems: the statistical effects of turbulence and the interface mass, momentum and energy transfers. The models developed in this study were introduced in the 3-D module of the CATHARE code developed by the CEA and the results were compared to experimental results available in the literature. The first chapter describes the equations of the local dual-fluid model for the 3-D description of two-phase flows. Closing relations adapted to dispersed flows with isothermal bubbles and without phase transformation are proposed and focus on the momentum transfer at the interfaces. The theoretical study of turbulence in the liquid phase of a bubble flow is modelled in chapter 2. Chapter 3 deals with the voluminal interface area used in the interface mass, momentum and energy transfers, and chapters 4 and 5 concern the application of the developed models to concrete situations. Chapter 4 describes in details the 3-D module of the CATHARE code while chapter 5 gives a comparison of numerical results obtained using the CATHARE code with other experimental results obtained at EdF. (J.S.)

  4. On The Validity of the Assumed PDF Method for Modeling Binary Mixing/Reaction of Evaporated Vapor in GAS/Liquid-Droplet Turbulent Shear Flow

    Science.gov (United States)

    Miller, R. S.; Bellan, J.

    1997-01-01

    An Investigation of the statistical description of binary mixing and/or reaction between a carrier gas and an evaporated vapor species in two-phase gas-liquid turbulent flows is perfomed through both theroetical analysis and comparisons with results from direct numerical simulations (DNS) of a two-phase mixing layer.

  5. A simple capacitance sensor for void fraction measurement in gas-liquid two-phase flow

    International Nuclear Information System (INIS)

    Silva, Luiz C.R.P.; Faccini, José L.H.; Farias, Marcos S.; Su, Jian

    2017-01-01

    In this work we present a simple and inexpensive capacitance sensor for time averaging void fraction measurement of gas-liquid two-phase flow, which was developed at Experimental Thermal hydraulics Laboratory in the Nuclear Engineering Institute, IEN/CNEN. The sensor is a non-invasive device causing no flow disturbances. It is formed by two parallel plates and four electronic circuits: a signal input circuit, an amplification circuit, a frequency generator, and a power supply circuit. The frequency generator applies a sinusoidal signal with appropriate frequency into the signal input circuit which converts the capacitance variation value (or void fraction) of the two-phase flow into a voltage signal that goes to the amplifier stage; the output signal of the amplifier stage will be an input to an analogic/digital converter, installed inside of a computer, and it will provide interpretation of the signal behavior. The capacitance sensor was calibrated by using a horizontal acrylic tube filled with a known volume of water. (author)

  6. A simple capacitance sensor for void fraction measurement in gas-liquid two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luiz C.R.P.; Faccini, José L.H.; Farias, Marcos S., E-mail: reina@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Su, Jian, E-mail: sujian@con.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Engenharia Nuclear

    2017-07-01

    In this work we present a simple and inexpensive capacitance sensor for time averaging void fraction measurement of gas-liquid two-phase flow, which was developed at Experimental Thermal hydraulics Laboratory in the Nuclear Engineering Institute, IEN/CNEN. The sensor is a non-invasive device causing no flow disturbances. It is formed by two parallel plates and four electronic circuits: a signal input circuit, an amplification circuit, a frequency generator, and a power supply circuit. The frequency generator applies a sinusoidal signal with appropriate frequency into the signal input circuit which converts the capacitance variation value (or void fraction) of the two-phase flow into a voltage signal that goes to the amplifier stage; the output signal of the amplifier stage will be an input to an analogic/digital converter, installed inside of a computer, and it will provide interpretation of the signal behavior. The capacitance sensor was calibrated by using a horizontal acrylic tube filled with a known volume of water. (author)

  7. The effects of a flow obstacle on liquid film flowing concurrently with air in a horizontal rectangular duct

    International Nuclear Information System (INIS)

    Fukano, Tohru; Tominaga, Akira; Morikawa, Kengo.

    1986-01-01

    The aspect of a liquid film flowing near a flat plate type obstacle was observed, and the liquid film thickness and the entrainment were measured under a wide range of gas and liquid flow rates. The results are summarized as follows: (1) The configurations of film flows near the obstacle are classified according to whether (a) the liquid film climbs over the obstacle or not, (b) the air flows under the obstacle or not, or (c) the liquid film swells or sinks just upstream or downstream of the obstacle. (2) The lower the liquid flow rate, the larger the effect of the obstacle on the film thickness. (3) The generation of entrainment is regulated by the obstacle when the air volumetric flux is high and by the disturbance wave when it is low. (author)

  8. Liquid flow rate effects during partial evaporation in a falling film micro contactor

    NARCIS (Netherlands)

    Moschou, P.; Croon, de M.H.J.M.; Schaaf, van der J.; Schouten, J.C.

    2013-01-01

    The focus of this study is the investigation of the effect of liquid flow rate on partial evaporation, enhanced by convective nitrogen flow, in a falling film micro contactor. Experiments are performed at different flow rates and for a certain heating liquid temperature. The temperatures of the gas

  9. Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower

    Directory of Open Access Journals (Sweden)

    Jafari Mohammad Javad

    2012-12-01

    Full Text Available Abstract The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p 3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream.

  10. Ecoulements diphasiques gaz-liquide à poches et à bouchons en conduites Two-Phase Gas-Liquid Slug Flow in Pipes

    Directory of Open Access Journals (Sweden)

    Ferschneider G.

    2006-11-01

    Full Text Available Les écoulements diphasiques gaz-liquide ont été étudiés afin de contribuer à développer des modèles de calculs prédictifs des pertes de charge dans les conduites de production des bruts pétroliers. Les expériences nécessaires ont été réalisées sur la boucle diphasique de Boussens dans les conditions suivantes représentatives des conditions industrielles : diamètre 6 , longueur 120 m, disposition de la conduite horizontale ou faiblement ascendante, couple de fluide gaz naturel-huile légère. Le gradient de pression, le contenu global, et la distribution locale des phases ont été mesurés. Le traitement des équations de conservation phasique intégrées sur la section par différents types de moyennes a permis de développer un modèle cellulaire qui inclue un nombre limité d'équations constitutives nécessaires à sa fermeture. Ce modèle prédétermine convenablement le gradient de pression, le contenu gaz global et la longueur des poches et des bouchons. Two-phase gas-liquid flows were analyzed so as to develop models for prediction of pressure drops in crude-oil production lines. The experiments were performed on the two-phase loop at Boussens under the following representative industrial conditions: 6 diameter, 120 m length, horizontal or slightly rising pipe, couple of fluids natural gas and light oil. The pressure gradient, average content and local phase distribution were measured. Conservation phase equations integrated along the cross-section were processed by different time-averaged operators so as to develop a cellular model including a limited number of constitutive equations required for its closure. This model suitably predetermines the pressure gradient, the average gas content and the length of gas and liquid slug.

  11. Low-gravity sensing of liquid/vapor interface and transient liquid flow

    Science.gov (United States)

    Jacobson, Saul A.; Korba, James M.; Lynnworth, Lawrence C.; Nguyen, Toan H.; Orton, George F.

    1987-03-01

    The work reported here deals mainly with tests on internally vaned cylindrical shell acrylic containers capped by hemispherical acrylic or aluminum end domes. Three different ultrasonic sensor techniques and one nucleonic technique presently are evaluated as possible solutions to the low-gravity liquid gauging problem. The ultrasonic techniques are as follows: use of a torsional wave sensor in which transit time is proportional to the integral of wetted distance x liquid density; integration of the flow rate output signal of a fast-response ultrasonic flowmeter; and use of multiplexed externally mounted 'point-sensor' transducers that sense transit times to liquid-gas interfaces. Using two commercial flowmeters and a thickness gauge modified for this particular project, bench tests were conducted at 1 g on liquids such as water, freon, and solvent 140, including both steady flow and pulsating flow with 40, 80, and 120 ms flow pulses. Subsequently, flight tests were conducted in the NASA KC-135 aircraft in which nearly 0-g conditions are obtainable for up to about 5 s in each of a number of repetitive parabolic flight trajectories. In some of these brief low-gravity flight tests freon was replaced with a higher-viscosity fuel to reduce sloshing and thereby obtain settled surfaces more quickly.

  12. Numerical simulation of gas-liquid two-phase flow behavior with condensation heat transfer

    International Nuclear Information System (INIS)

    Takamori, Kazuhide; Murase, Michio; Baba, Yoshikazu; Aihara, Tsuyoshi.

    1995-01-01

    In this study, condensation heat transfer experiments were performed in order to verify a condensation heat transfer model coupled with a three-dimensional two-phase flow analysis. In the heat transfer model, the liquid film flow rate on the heat transfer tubes was calculated by a mass balance equation and the liquid film thickness was calculated from the liquid film flow rate using Nusselt's laminar flow model and Fujii's equation for steam velocity effect. In the experiments, 112 horizontal staggered tubes with an outer diameter of 16 mm and length of 0.55 m were used. Steam and spray water were supplied to the test section, and inlet quality was controlled by the spray water flow rate. The temperature was 100degC and the pressure was 0.1 MPa. The overall heat transfer coefficients were measured for inlet quality of 13-100%. From parameter calculations for the falling liquid film ratio from the upper tubes to the lower tubes, the calculated overall heat transfer coefficients agreed with the data to within ±5% at the falling liquid film ratio of 0.7. (author)

  13. Determination of flow rates of oil, water and gas in pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Roach, G J; Watt, J S; Zastawny, H W [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lucas Heights, NSW (Australia). Div. of Mineral Physics

    1994-12-31

    This paper describes a multiphase flow meter developed by CSIRO for determining of the flow rates of oil, water and gas in high pressure pipelines, and the results of a trial of this flow meter on an offshore oil platform. Two gamma-ray transmission gauges are mounted about a pipeline carrying the full flow of oil, water and gas. The flow rates are determined by combining single energy gamma-ray transmission measurements which determine the mass per unit area of fluids in the gamma-ray beam as a function of time, dual energy gamma-ray transmission (DUET) which determine the approximate mass fraction of oil in the liquids, cross-correlation of gamma-ray transmission measurements, with one gauge upstream of the other, which determines flow velocity, pressure and temperature measurements, and knowledge of the specific gravities of oil and (salt) water, and solubility of the gas in the liquids, all as a function of pressure and temperature. 3 figs.

  14. Determination of flow rates of oil, water and gas in pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Roach, G.J.; Watt, J.S.; Zastawny, H.W. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lucas Heights, NSW (Australia). Div. of Mineral Physics

    1993-12-31

    This paper describes a multiphase flow meter developed by CSIRO for determining of the flow rates of oil, water and gas in high pressure pipelines, and the results of a trial of this flow meter on an offshore oil platform. Two gamma-ray transmission gauges are mounted about a pipeline carrying the full flow of oil, water and gas. The flow rates are determined by combining single energy gamma-ray transmission measurements which determine the mass per unit area of fluids in the gamma-ray beam as a function of time, dual energy gamma-ray transmission (DUET) which determine the approximate mass fraction of oil in the liquids, cross-correlation of gamma-ray transmission measurements, with one gauge upstream of the other, which determines flow velocity, pressure and temperature measurements, and knowledge of the specific gravities of oil and (salt) water, and solubility of the gas in the liquids, all as a function of pressure and temperature. 3 figs.

  15. Determination of flow rates of oil, water and gas in pipelines

    International Nuclear Information System (INIS)

    Roach, G.J.; Watt, J.S.; Zastawny, H.W.

    1993-01-01

    This paper describes a multiphase flow meter developed by CSIRO for determining of the flow rates of oil, water and gas in high pressure pipelines, and the results of a trial of this flow meter on an offshore oil platform. Two gamma-ray transmission gauges are mounted about a pipeline carrying the full flow of oil, water and gas. The flow rates are determined by combining single energy gamma-ray transmission measurements which determine the mass per unit area of fluids in the gamma-ray beam as a function of time, dual energy gamma-ray transmission (DUET) which determine the approximate mass fraction of oil in the liquids, cross-correlation of gamma-ray transmission measurements, with one gauge upstream of the other, which determines flow velocity, pressure and temperature measurements, and knowledge of the specific gravities of oil and (salt) water, and solubility of the gas in the liquids, all as a function of pressure and temperature. 3 figs

  16. Bubble parameters analysis of gas-liquid two-phase sparse bubbly flow based on image method

    International Nuclear Information System (INIS)

    Zhou Yunlong; Zhou Hongjuan; Song Lianzhuang; Liu Qian

    2012-01-01

    The sparse rising bubbles of gas-liquid two-phase flow in vertical pipe were measured and studied based on image method. The bubble images were acquired by high-speed video camera systems, the characteristic parameters of bubbles were extracted by using image processing techniques. Then velocity variation of rising bubbles were drawn. Area and centroid variation of single bubble were also drawn. And then parameters and movement law of bubbles were analyzed and studied. The test results showed that parameters of bubbles had been analyzed well by using image method. (authors)

  17. Measurements of gas permeability and non-Darcy flow in gas-water-hydrate systems

    Energy Technology Data Exchange (ETDEWEB)

    Ersland, G.; Husebo, J.; Graue, A.; Kvamme, B. [Bergen Univ., Bergen (Norway). Dept. of Physics and Technology; Baldwin, B. [Green Country Petrophysics LLC, Dewey, OK (United States); Stevens, J.; Howard, J. [ConocoPhillips, OK (United States)

    2008-07-01

    Storage of carbon dioxide (CO{sub 2}) in natural gas hydrate reservoirs may offer stable long-term storage of a greenhouse gas while benefiting from methane production, without requiring heat. By exposing hydrate to a thermodynamically preferred hydrate former, CO{sub 2}, the hydrate may be maintained macroscopically in the solid state and retain the stability of the formation. However, there is concern over the flow capacity in such reservoirs. This depends on several factors, notably thermodynamic destabilization of hydrate in small pores due to capillary effects; the presence of liquid channels separating the hydrate from the mineral surfaces; and, the connectivity of gas or liquid filled pores and channels. This paper described a technique for measuring gas permeability in gas-water-hydrate systems. It reported on several experiments that measured gas permeability during stages of hydrate growth in sandstone core plugs. Interactions between minerals and surrounding molecules were also discussed. The formation of methane hydrate in porous media was monitored and quantified with magnetic resonance imaging (MRI). MRI images of hydrate growth within the porous rock were provided along with measurements of gas permeability and non-Darcy flow effects at various hydrate saturations. Gas permeability was measured at steady state flow of methane through the hydrate-bearing core sample. Significant gas permeability was recorded for porous sandstone even when hydrates occupied up to 60 per cent of the pore space. It was concluded that MRI imaging can be used effectively to map and quantify hydrate saturation in sandstone core plugs. 27 refs., 2 tabs., 10 figs.

  18. Hydrodynamics in a cocurrent gas-liquid trickle bed at elevated pressures

    OpenAIRE

    Wammes, W.J.A.; Middelkamp, J.; Huisman, W.J.; Huisman, W.J.; de Baas, C.M.; de Baas, C.M.; Westerterp, K.R.

    1991-01-01

    Data on design and operation of trickle beds at elevated pressures are scarce. In this study the influence of the gas density on the liquid holdup, the pressure drop, and the transition between trickle and pulse flow has been investigated in a tricklebed reactor operating up to 7.5 MPa and with nitrogen or helium as the gas phase. Gas-liquid interfacial areas have been determined up to 5.0 MPa by means of CO2 absorption from CO2/N2 gas mixtures into amine solutions. A comparison of the result...

  19. Characteristics of Gas-liquid Mass Transfer and Interfacial Area in a Bubble Column

    International Nuclear Information System (INIS)

    Lim, Dae Ho; Yoo, Dong Jun; Kang, Yong

    2015-01-01

    Characteristics of gas-liquid mass transfer and interfacial area were investigated in a bubble column of diameter and height of 0.102 m and 2.5 m, respectively. Effects of gas and liquid velocities on the volumetric gas-liquid mass transfer coefficient (k L a), interfacial area (a) and liquid side true mass transfer coefficient (k L ) were examined. The interfacial area and volumetric gas-liquid mass transfer coefficient were determined directly by adopting the simultaneous physical desorption of O 2 and chemical absorption of CO 2 in the column. The values of k L a and a increased with increasing gas velocity but decreased with increasing liquid velocity in the bubble column which was operated in the churn turbulent flow regime. The value of k L increased with increasing gas velocity but did not change considerably with increasing liquid velocity. The liquid side mass transfer was found to be related closely to the liquid circulation as well as the effective contacting frequency between the bubbles and liquid phases

  20. Characteristics of Gas-liquid Mass Transfer and Interfacial Area in a Bubble Column

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Dae Ho; Yoo, Dong Jun; Kang, Yong [Chungnam National University, Daejeon (Korea, Republic of)

    2015-02-15

    Characteristics of gas-liquid mass transfer and interfacial area were investigated in a bubble column of diameter and height of 0.102 m and 2.5 m, respectively. Effects of gas and liquid velocities on the volumetric gas-liquid mass transfer coefficient (k{sub L}a), interfacial area (a) and liquid side true mass transfer coefficient (k{sub L}) were examined. The interfacial area and volumetric gas-liquid mass transfer coefficient were determined directly by adopting the simultaneous physical desorption of O{sub 2} and chemical absorption of CO{sub 2} in the column. The values of k{sub L}a and a increased with increasing gas velocity but decreased with increasing liquid velocity in the bubble column which was operated in the churn turbulent flow regime. The value of k{sub L} increased with increasing gas velocity but did not change considerably with increasing liquid velocity. The liquid side mass transfer was found to be related closely to the liquid circulation as well as the effective contacting frequency between the bubbles and liquid phases.

  1. Study of void fraction and mixing of immiscible liquids in a pool configuration by an upward gas flow

    International Nuclear Information System (INIS)

    Casas, J.C.; Corradini, M.L.

    1992-01-01

    In this paper, investigations are performed to study the mixing between immiscible liquids in a pool configuration due to an upward gas flow. A water-R113 system is sued in the bubbly/churn-turbulent regimes to determine the effects of the unagitated pool depth on layer mixing. The superficial gas velocity at which full mixing is attained is observed to increase with the pool depth, although it is concluded that this is a weak dependency. Mixing in the churn-turbulent regime is studied with Wood's metal-water and Wood's metal-silicone fluid (100 cS) as pairs of fluids. Additional past mixing data from six other fluids are also included in the data base. A criterion is proposed to determine if two liquids will entrain in bubbly or churn-turbulent flow. Correlations are derived that, for a set of given conditions, allow prediction of the mixing state (mixed or segregated) of a system. Because of the indirect method of measuring the mixed layer thickness, pool void fraction experiments are also performed. For the case of water and R113, the effect of unagitated pool depth on the void fraction is studied

  2. A heat exchanger between forced flow helium gas at 14 to 18 K and liquid hydrogen at 20 K circulated by natural convection

    International Nuclear Information System (INIS)

    Green, M.A.; Ishimoto, S.; Lau, W.; Yang, S.

    2003-01-01

    The Muon Ionization Cooling Experiment (MICE) has three 350-mm long liquid hydrogen absorbers to reduce the momentum of 200 MeV muons in all directions. The muons are then re-accelerated in the longitudinal direction by 200 MHz RF cavities. The result is cooled muons with a reduced emittance. The energy from the muons is taken up by the liquid hydrogen in the absorber. The hydrogen in the MICE absorbers is cooled by natural convection to the walls of the absorber that are in turn cooled by helium gas that enters at 14 K. This report describes the MICE liquid hydrogen absorber and the heat exchanger between the liquid hydrogen and the helium gas that flows through passages in the absorber wall

  3. Analysis of Simultaneous Gas-Liquid Flow Through an Orifice and Its Application to Flow Metering Etude de l'écoulement simultané d'un mélange gaz-liquide à travers un orifice et son application à la mesure du débit

    Directory of Open Access Journals (Sweden)

    Pascal H.

    2006-11-01

    Full Text Available The purpose of this article is to show a more accurate orifice equation for a two-phase flow, such a compressible mixture of gas and liquid. The orifice equation given here con be used for the measurement of a gas-liquid mixture of fine emulsions by the orificemeter method. From the thermodynamic point of view, an equation of state has been formulated which provides the relationship between the specific mass of the mixture and pressure, under conditions of adiabatic expansion. The results obtained enable the mass flow rates of gas and liquid ta be determined without separation of the phases, provided thot the gas liquid mass ratio is known. The critical pressure ratio corresponding ta sonic velocity is also determined. Cet article présente une relation plus précise pour l'écoulement d'un système à deux phases, tel qu'un mélange compressible gaz-liquide, à travers un diaphragme. Cette relation peut être utilisée pour des mesures de mélanges gaz-liquide très finement divisés, c'est-à-dire des émulsions ou brouillards, par la méthode du diaphragme en paroi mince. Du point de vue thermodynamique, on a formulé une équation d'état donnant la relation entre la masse spécifique du mélange et la pression dans des conditions d'expansion adiabatique. Les résultats obtenus per-mettent de déterminer le débit massique du gaz et du liquide, sans séparation des deux phases, à condition que le rapport de masse gaz-liquide soit connu. On détermine également le rapport de pression critique correspondantà la vitesse du son.

  4. Multiphase flow and transport caused by spontaneous gas phase growth in the presence of dense non-aqueous phase liquid.

    Science.gov (United States)

    Roy, James W; Smith, James E

    2007-01-30

    Disconnected bubbles or ganglia of trapped gas may occur below the top of the capillary fringe through a number of mechanisms. In the presence of dense non-aqueous phase liquid (DNAPL), the disconnected gas phase experiences mass transfer of dissolved gases, including volatile components from the DNAPL. The properties of the gas phase interface can also change. This work shows for the first time that when seed gas bubbles exist spontaneous gas phase growth can be expected to occur and can significantly affect water-gas-DNAPL distributions, fluid flow, and mass transfer. Source zone behaviour was observed in three different experiments performed in a 2-dimensional flow cell. In each case, a DNAPL pool was created in a zone of larger glass beads over smaller glass beads, which served as a capillary barrier. In one experiment effluent water samples were analyzed to determine the vertical concentration profile of the plume above the pool. The experiments effectively demonstrated a) a cycle of spontaneous gas phase expansion and vertical advective mobilization of gas bubbles and ganglia above the DNAPL source zone, b) DNAPL redistribution caused by gas phase growth and mobilization, and c) that these processes can significantly affect mass transport from a NAPL source zone.

  5. High pressure flow reactor for in situ X-ray absorption spectroscopy of catalysts in gas-liquid mixtures—A case study on gas and liquid phase activation of a Co-Mo/Al2O3 hydrodesulfurization catalyst

    NARCIS (Netherlands)

    van Haandel, L.; Hensen, E.J.M.; Weber, Th.

    2017-01-01

    An in situ characterization of heterogeneous catalysts under industrial operating conditions may involve high pressure and reactants in both the gas and the liquid phase. In this paper, we describe an in situ XAS flow reactor, which is suitable to operate under such conditions (pmax 20 bar, Tmax 350

  6. Multiscale Simulation of Gas Film Lubrication During Liquid Droplet Collision

    Science.gov (United States)

    Chen, Xiaodong; Khare, Prashant; Ma, Dongjun; Yang, Vigor

    2012-02-01

    Droplet collision plays an elementary role in dense spray combustion process. When two droplets approach each other, a gas film forms in between. The pressure generated within the film prevents motion of approaching droplets. This fluid mechanics is fluid film lubrication that occurs when opposing bearing surfaces are completely separated by fluid film. The lubrication flow in gas film decides the collision outcome, coalescence or bouncing. Present study focuses on gas film drainage process over a wide range of Weber numbers during equal- and unequal-sized droplet collision. The formulation is based on complete set of conservation equations for both liquid and surrounding gas phases. An improved volume-of-fluid technique, augmented by an adaptive mesh refinement algorithm, is used to track liquid/gas interfaces. A unique thickness-based refinement algorithm based on topology of interfacial flow is developed and implemented to efficiently resolve the multiscale problem. The grid size on interface is up O(10-4) of droplet size with a max resolution of 0.015 μm. An advanced visualization technique using the Ray-tracing methodology is used to gain direct insights to detailed physics. Theories are established by analyzing the characteristics of shape changing and flow evolution.

  7. CFD Validation of Gas Injection in Flowing Mercury over Vertical Smooth and Grooved Wall

    International Nuclear Information System (INIS)

    Abdou, Ashraf A.; Wendel, Mark W.; Felde, David K.; Riemer, Bernie

    2009-01-01

    The Spallation Neutron Source (SNS) is an accelerator-based neutron source at Oak Ridge National Laboratory (ORNL). The nuclear spallation reaction occurs when a proton beam hits liquid mercury. This interaction causes thermal expansion of the liquid mercury which produces high pressure waves. When these pressure waves hit the target vessel wall, cavitation can occur and erode the wall. Research and development efforts at SNS include creation of a vertical protective gas layer between the flowing liquid mercury and target vessel wall to mitigate the cavitation damage erosion and extend the life time of the target. Since mercury is opaque, computational fluid dynamics (CFD) can be used as a diagnostic tool to see inside the liquid mercury and guide the experimental efforts. In this study, CFD simulations of three dimensional, unsteady, turbulent, two-phase flow of helium gas injection in flowing liquid mercury over smooth, vertically grooved and horizontally grooved walls are carried out with the commercially available CFD code Fluent-12 from ANSYS. The Volume of Fluid (VOF) model is used to track the helium-mercury interface. V-shaped vertical and horizontal grooves with 0.5 mm pitch and about 0.7 mm depth were machined in the transparent wall of acrylic test sections. Flow visualization data of helium gas coverage through transparent test sections is obtained with a high-speed camera at the ORNL target test facility (TTF). The helium gas mass flow rate is 8 mg/min and introduced through a 0.5 mm diameter port. The local mercury velocity is 0.9 m/s. In this paper, the helium gas flow rate and the local mercury velocity are kept constant for the three cases. Time integration of predicted helium gas volume fraction over time is done to evaluate the gas coverage and calculate the average thickness of the helium gas layer. The predicted time-integrated gas coverage over vertically grooved and horizontally grooved test sections is better than over a smooth wall. The

  8. Effect of geometric parameters of liquid-gas separator units on phase separation performance

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Songping; Chen, Xueqing; Chen, Ying [Guangdong University of Technology, Seoul (China); Yang, Zhen [Tsinghua University, Beijing (China)

    2015-07-15

    Five liquid-gas separator units were designed and constructed based on a new concept of a validated high-performance condenser. Each separator unit consists of two united T-junctions and an apertured baffle. The separator units have different header diameters or different baffles with different diameters of the liquid-gas separation hole. The phase separation characteristics of the units were investigated at inlet air superficial velocities from 1.0m/s to 33.0m/s and water superficial velocities from 0.0015 m/s to 0..50 m/s. The experimental results showed that the liquid height, liquid flow rate through the separation hole, and liquid separation efficiency increased with increased header diameter and decreased diameter of the separation hole. The geometric structures of the separator units affected the phase separation characteristics by influencing the liquid height in the header and the liquid flow rate through the separation hole.

  9. Numerical analysis of gas-liquid two-phase flow in secondary side of steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Murase, Michio; Nakamura, Akira; Yagi, Yoshinori [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan)

    2002-09-01

    The steam generator (SG) in a pressurized water reactor (PWR) is an important two-phase flow component as the boundary between the primary loop and the secondary loop. In this study, we performed gas-liquid two-phase flow analyses for SG reliability tests conduced by Nuclear Power Engineering Corporation (NUPEC) using the two-fluid model of a thermal-hydraulic computer code PHOENICS. In order to calculate the location of the boiling initiation accurately, detailed inputs were required for the friction coefficients affecting the velocity distribution and the heat transfer distribution. However, the velocity and heat transfer distributions did not greatly affect the void fractions in the upper region of the heat transfer tubes. The calculated void fractions agreed with the measured values within 4% as the local average and within 2% as an average in a cross-section, except the region of low void fractions. (author)

  10. Measuring method of liquid flow behavior using visualization

    International Nuclear Information System (INIS)

    Serizawa, Akimi; Kamei, Takashi; Takahashi, Osamu; Kawara, Zensaku

    1994-01-01

    It is important for the safety of nuclear reactor to understand the behavior of gas-liquid two-phase flow. For that analysis, we have to understand its time and spatial dependence. But most of the measuring methods applied to two-phase flow experiments are not enough for this purpose, because they consider the time averaged value, and they are put on the local position in test sections. Standing on such a point of view, we have been developing a measuring method using fluorescence. And from those pictures gotten by video camera, after processed by computer, we measure liquid film thickness. (author)

  11. Water-saving liquid-gas conditioning system

    Science.gov (United States)

    Martin, Christopher; Zhuang, Ye

    2014-01-14

    A method for treating a process gas with a liquid comprises contacting a process gas with a hygroscopic working fluid in order to remove a constituent from the process gas. A system for treating a process gas with a liquid comprises a hygroscopic working fluid comprising a component adapted to absorb or react with a constituent of a process gas, and a liquid-gas contactor for contacting the working fluid and the process gas, wherein the constituent is removed from the process gas within the liquid-gas contactor.

  12. Numerical modelling of isothermal gas-liquid two-phase bubbly flow in vertical pipes

    International Nuclear Information System (INIS)

    Yamoah, S.

    2014-07-01

    In order to qualify CFD codes for accurate numerical predictions of transient evolution of flow regimes in a vertical gas-liquid two-phase flow, suitable closure models are needed. The current study focuses on detailed numerical investigation of the interfacial driving force models and assessment of two population balance model approaches viz. the MUltiple-Size-Group (MUSIG) and one-group Interfacial Area Transport Equation (lATE) using the two-fluid modelling approach. Numerical predictions of five primitive variables: gas volume fraction, interfacial area concentration, Sauter mean bubble diameter, gas velocity and liquid velocity; have been validated against experimental data of Monros et al., (2013). Three specific objectives have been completed in this study. Firstly, under the assumption of mono-disperse bubbles, a consistent set of interfacial force models have been investigated. The effect of drag, lift, wall lubrication and turbulent dispersion forces has been assessed. New parameters have been introduced in the wall lubrication force models of Antal et al., (1991) and Frank et al., (2004, 2008) as well as implementing additional drag coefficient models using CFX Expression Language (CEl). The Tomiyama, (1998) lift coefficient model has been modified in this study. In general, the predictions from the sets of interfacial force models yielded satisfactory agreement with the experimental data. A set of Grace drag coefficient model, Tomiyama lift coefficient model, Antal wall force model, and Favre averaged turbulent dispersion force were found to provide the best agreement with the experimental data. Secondly, a model validation study to assess the performance of existing coalescence and breakup models of the MUSIG model in simulating bubbly flow in vertical configuration has been conducted. The breakup model of Luo and Svendsen, (1996) and coalescence model of Prince and Blanch, (1990) have been implemented. Detailed analysis has been performed for the wall

  13. Correlations of drift velocity for gas-liquid two-phase flow in rod bundle

    International Nuclear Information System (INIS)

    Kataoka, Isao; Matsuura, Keizo; Serizawa, Akimi

    2004-01-01

    A new correlation was developed for the drift velocity for low inlet liquid flux in rod bundle. Based on authors' previous analysis of drift velocity for large diameter pipe, an analysis was made on the drift velocity in rod bundle. It is assumed that the large bubble of which size is several subchannel diameter behaves as slug bubble. Under this assumption, it becomes very important how to define equivalent diameter for rod bundle. In view of physical consideration of slug bubble behavior and previous analysis, an equivalent diameter based on the wetted perimeter was found to be most appropriate. Using this equivalent diameter, experimental data of drift velocity in rod bundle were correlated with dimensional analysis. It was found out that for small diameter (dimensionless diameter less than 48) drift velocity increased with square root of diameter which is same dependency of ordinary slug flow correlation. For larger diameter (dimensionless diameter is more than 48), drift velocity is almost constant and same as that of dimensionless diameter of 48. The physical meaning of this result was considered to be the instability of interface of large slug bubble. The density ratio between gas and liquid and viscosity of liquid phase were found to be the main parameters which affect the drift velocity. This is physically reasonable because density ratio is related to the buoyancy force and liquid viscosity is related to shear force near solid wall. The experimental data were correlated by density ratio and dimensionless liquid viscosity. The obtained dimensionless correlation for the drift velocity in rod bundle successfully correlated experimental data for various rod bundles (equivalent diameters), pressures, liquid fluxes etc. It is also consistent with the drift flux correlation for round tube. (author)

  14. Removing well bore liquid blockage by gas injection

    International Nuclear Information System (INIS)

    Ahmed, Tarek

    2000-01-01

    Gas condensate reservoirs have long presented production problems when the pressure around the well bore drops below the dew point pressure. The formation of the condensate around the well bore can be thought of as an additional 'skin' that causes a reduction in the gas flow rates. Many processes have been used successfully to prevent or reduce the formation of liquids within the entire reservoir, such as pressure maintenance schemes and gas cycling processes. The pressure maintenance scheme is designed to keep the reservoir pressure at or above the dew point pressure while the gas cycling process is intended to reduce the liquid dropout by vaporization.Often times the pressure in the near-well bore region of the reservoir falls below the dew point pressure, while the pressure in the reservoir remains higher than the dew point pressure. As the near-well bore pressure drops below the dew point pressure, retrograde condensation occurs leading to the formation and then the mobilization of the condensate phase towards the producing wells. The liquid phase accumulates in the near Well bore region, forming a ring, which progressively reduces the gas deliverability. This study is designed to provide an insight into the mechanism of gas injection process in reducing gas-well productivity losses due to condensate blocking in the near well bore region. The study also evaluates the effectiveness of lean gas, N 2 , and CO 2 Huff 'n' Puff injection technique in removing the liquid dropout accumulation in and around the well bore. Results of the study show the importance of selecting the optimum injection volume and pressure. (author)

  15. Investigation of liquid phase axial dispersion in Taylor bubble flow by radiotracer residence time distribution analysis

    Directory of Open Access Journals (Sweden)

    Jin J.H.

    2013-05-01

    Full Text Available A gas-liquid Taylor bubble flow occurs in small diameter channels in which gas bubbles are separated by slugs of pure liquid. This type of flow regime is well suited for solid catalyzed gas-liquid reactors in which the reaction efficiency is a strong function of axial dispersion in the regions of pure liquid. This paper presents an experimental study of liquid phase axial dispersion in a Taylor bubble flow developed in a horizontal tube using high speed photography and radiotracer residence time distribution (RTD analysis. A parametric dependence of axial dispersion on average volume fraction of gas phase was also investigated by varying the relative volumetric flow rates of the two phases. 137mBa produced from a 137Cs/137mBa radionuclide generator was used as radiotracer and measurements were made using the NaI(Tl scintillation detectors. Validation of 137mBa in the form of barium chloride as aqueous phase radiotracer was also carried out. Axial Dispersion Model (ADM was used to simulate the hydrodynamics of the system and the results of the experiment are presented. It was observed that the system is characterized by very high values of Peclet Number (Pe∼102 which reveals an approaching plug type flow. The experimental and model estimated values of mean residence times were observed in agreement with each other.

  16. Modeling of the evolution of bubble size distribution of gas-liquid flow inside a large vertical pipe. Influence of bubble coalescence and breakup models

    International Nuclear Information System (INIS)

    Liao, Yixiang; Lucas, Dirk

    2011-01-01

    The range of gas-liquid flow applications in today's technology is immensely wide. Important examples can be found in chemical reactors, boiling and condensation equipments as well as nuclear reactors. In gas-liquid flows, the bubble size distribution plays an important role in the phase structure and interfacial exchange behaviors. It is therefore necessary to take into account the dynamic change of the bubble size distribution to get good predictions in CFD. An efficient 1D Multi-Bubble-Size-Class Test Solver was introduced in Lucas et al. (2001) for the simulation of the development of the flow structure along a vertical pipe. The model considers a large number of bubble classes. It solves the radial profiles of liquid and gas velocities, bubble-size class resolved gas fraction profiles as well as turbulence parameters on basis of the bubble size distribution present at the given axial position. The evolution of the flow along the height is assumed to be solely caused by the progress of bubble coalescence and break-up resulting in a bubble size distribution changing in the axial direction. In this model, the bubble coalescence and breakup models are very important for reasonable predictions of the bubble size distribution. Many bubble coalescence and breakup models have been proposed in the literature. However, some obvious discrepancies exist in the models; for example, the daughter bubble size distributions are greatly different from different bubble breakup models, as reviewed in our previous publication (Liao and Lucas, 2009a; 2010). Therefore, it is necessary to compare and evaluate typical bubble coalescence and breakup models that have been commonly used in the literature. Thus, this work is aimed to make a comparison of several typical bubble coalescence and breakup models and to discuss in detail the ability of the Test Solver to predict the evolution of bubble size distribution. (orig.)

  17. Bubble-induced mixing of two horizontal liquid layers with non-uniform gas injection at the bottom

    International Nuclear Information System (INIS)

    Cheung, F.B.; Pedersen, D.R.; Leinweber, G.

    1986-01-01

    During a postulated severe core meltdown accident in an LMFBR, a large amount of sodium coolant may spill into the reactor concrete cavity. A layer of liquid products may form as a result of the sodium-concrete reactions. The liquid product layer, which is highly viscous and much heavier than sodium, separates the concrete from the sodium pool. In general, the downward transport of sodium through the liquid product layer to the unreacted concrete surface, which controls the rate of chemical erosion of the concrete, depends strongly on the agitation induced by gas evolution from the heated concrete. In this study, experiments were conducted to explore the effect of non-uniform gas injection on mixing of two horizontal mutually soluble liquid layers. The liquid in the lower layer was chosen to be more viscous and heavier than the liquid in the upper layer. To simulate the reactor accident situation, gas was injected at the bottom of the liquid-liquid system through a circular hole that covered only the center portion of the bottom surface of the lower liquid layer. The bubble-induced mixing motions were observed and the rate of mixing was measured for different hole sizes and various gas flow rates. The results of this study clearly show that the rate of gas injection is not the only parameter controlling the mixing of the liquid-liquid system. The effect of non-uniform gas injection is important at high gas flow rates. Within the present experimental conditions, the reduction in the overall mixing rate can be as large as a factor of three

  18. Huff 'n puff to revaporize liquid dropout in an Omani gas field

    Energy Technology Data Exchange (ETDEWEB)

    Al-Wadhahi, M.; Boukadi, F.H.; Al-Bemani, A.; Al-Maamari, R.; Al-Hadrami, H. [Department of Petroleum and Chemical Engineering, Sultan Qaboos University, P.O. Box 33, Al-Khod 123 (Oman)

    2007-01-15

    In this study, Huff 'n Puff technique is used as a production mechanism to revaporize liquid dropout in the Saih Rawl retrograde condensate gas field, Oman. During the huff cycle, a number of wells were shut in to achieve revaporization. The same wells were put on stream, during the puff cycle. Liquid dropout induced a mechanical skin around the wellbore and hampered gas production capabilities but has been revaporized through pressurization. The pressure buildup in the rich-gas condensate reservoir was due to a cross flow originating from a deeper highly pressurized lean-gas bearing formation. The pressure communication was taking place through the wellbore during shut-in cycles. A compositional simulation model was used to confirm the theory of condensate revaporization. Simulation results indicated that Huff 'n Puff is a viable production technique. The technique improved gas deliverability and enhanced gas-liquid production by minimizing the skin caused by gas-liquid dropout. (author)

  19. The Effect of Inclination Angle on Critical Heat Flux in a Locally Heated Liquid Film Moving Under the Action of Gas Flow in a Mini-Channel

    Directory of Open Access Journals (Sweden)

    Tkachenko Egor M.

    2016-01-01

    Full Text Available Intensively evaporating liquid films moving under the action of the cocurrent gas flow in a microchannel are promising for the use in modern cooling systems of semiconductor devices with high local heat release. This work has studied the dependence of the critical heat flux on the inclination angle of the channel. It has been found that the inclination angle in the plane parallel to the flow has no significant effect on the critical heat flux. Whereas the inclination angle in the plane perpendicular to the flow, on the contrary, significantly changes the value of the critical heat flux. However, for a given flow rate of fluid there is a threshold gas velocity at which the critical heat flux does not differ from the case of zero inclination of the channel. Thus, it can be concluded that the cooling system based on shear-driven liquid films can be potentially used when direction of the gravity changes.

  20. Flow pattern-based mass and heat transfer and frictional drag of gas-non-Newtonian liquid flow in helical coil: two- and three-phase systems

    Science.gov (United States)

    Thandlam, Anil Kumar; Das, Chiranjib; Majumder, Subrata Kumar

    2017-04-01

    Investigation of wall-liquid mass transfer and heat transfer phenomena with gas-Newtonian and non-Newtonian fluids in vertically helical coil reactor have been reported in this article. Experiments were conducted to investigate the effect of various dynamic and geometric parameters on mass and heat transfer coefficients in the helical coil reactor. The flow pattern-based heat and mass transfer phenomena in the helical coil reactor are highlighted at different operating conditions. The study covered a wide range of geometric parameters such as diameter of the tube ( d t ), diameter of the coil ( D c ), diameter of the particle ( d p ), pitch difference ( p/D c ) and concentrations of non-Newtonian liquid. The correlation models for the heat and mass transfer coefficient based on the flow pattern are developed which may be useful in process scale-up of the helical coil reactor for industrial application. The frictional drag coefficient was also estimated and analyzed by mass transfer phenomena based on the electrochemical method.

  1. Influence of oxygen gas on characteristics of self-organized luminous pattern formation observed in an atmospheric dc glow discharge using a liquid electrode

    International Nuclear Information System (INIS)

    Shirai, Naoki; Uchida, Satoshi; Tochikubo, Fumiyoshi

    2014-01-01

    Self-organized luminous pattern formation is observed in the liquid surface of an atmospheric dc glow discharge using a liquid electrode with a miniature helium flow. The factors affecting pattern formation are the gap length, discharge current, helium mass flow rate and polarity. The pattern shape depends on the conductivity and temperature of the liquid electrode. A variety of patterns were observed by changing the conductivity and temperature of the liquid. We clarified that the self-organized pattern formation depends on the amount of electronegative gas, such as oxygen, in the gas in the electrode gap. When an oxygen gas flow was fed to the liquid surface from the outside in an obliquely downward direction, namely, the amount of oxygen gas on the liquid surface was increased locally, self-organized pattern formation was observed in the region with the increased amount of oxygen gas. When the amount of oxygen in the gas in the gap was changed by using a sheath flow system, the appearance of the pattern changed. The presence of oxygen gas strongly affected the self-organized pattern formation of the atmospheric dc discharge using a liquid anode. (paper)

  2. Investigation of the Extinguishing Features for Liquid Fuels and Organic Flammable Liquids Atomized by a Water Flow

    Directory of Open Access Journals (Sweden)

    Voytkov Ivan V.

    2016-01-01

    Full Text Available The processes of heat and mass transfer were investigated experimentally while moving and evaporating the atomized water flow in high-temperature combustion products of typical liquid fuels and organic flammable liquids: gasoline, kerosene, acetone, crude oil, industrial alcohol. We determined typical periods of liquid extinguishing by an atomized water flow of various dispersability. Data of the discharge of extinguishing medium corresponding to various parameters of atomization and duration of using the atomization devices was presented. It is shown that Um≈3.5 m/s is a minimal outflow velocity of droplets during moving while passing the distance of 1m in the high-temperature gas medium to stop the combustion of organic liquids.

  3. Numerical modelling of inert gas bubble rising in liquid metal pool

    International Nuclear Information System (INIS)

    Pradeep, Arjun; Sharma, Anil Kumar; Ponraju, D.; Nashine, B K.

    2016-01-01

    Two-phase flow finds several applications in safe operation of Sodium-cooled Fast Reactor (SFR). Numerical modelling of bubble rise dynamics in liquid metal pool of SFR is essential for the evaluation of residence time and shape changes, which are of utmost importance for simulating associated heat and mass transfer processes involved in reactor safety. A numerical model has been developed based on OpenFOAM for the evaluation of two-dimensional inert gas bubble rise dynamics in stagnant liquid metal pool. The governing model equations are discretized and solved using the Volume of Fluid based solver available in OpenFOAM with appropriate initial and boundary conditions. The model has been validated with available numerical benchmark results for laminar transient two-phase flow. The model has been used to evaluate velocity and rise trajectory of argon gas bubble with different diameters through a pool of liquid sodium. (author)

  4. US crude oil, natural gas, and natural gas liquids reserves

    International Nuclear Information System (INIS)

    1992-01-01

    This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1991, as well as production volumes for the United States, and selected States and State subdivisions for the year 1991. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), its two major components (nonassociated and associated-dissolved gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, two components of natural gas liquids, lease condensate and natural gas plant liquids, have their reserves and production data presented. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. A discussion of notable oil and gas exploration and development activities during 1991 is also presented

  5. Gas Enrichment at Liquid-Wall Interfaces

    NARCIS (Netherlands)

    Dammer, S.M.; Lohse, Detlef

    2006-01-01

    Molecular dynamics simulations of Lennard-Jones systems are performed to study the effects of dissolved gas on liquid-wall and liquid-gas interfaces. Gas enrichment at walls, which for hydrophobic walls can exceed more than 2 orders of magnitude when compared to the gas density in the bulk liquid,

  6. Characterization of linear interfacial waves in a turbulent gas-liquid pipe flow

    Science.gov (United States)

    Ayati, A. A.; Farias, P. S. C.; Azevedo, L. F. A.; de Paula, I. B.

    2017-06-01

    The evolution of interfacial waves on a stratified flow was investigated experimentally for air-water flow in a horizontal pipe. Waves were introduced in the liquid level of stratified flow near the pipe entrance using an oscillating plate. The mean height of liquid layer and the fluctuations superimposed on this mean level were captured using high speed cameras. Digital image processing techniques were used to detect instantaneous interfaces along the pipe. The driving signal of the oscillating plate was controlled by a D/A board that was synchronized with acquisitions. This enabled to perform phase-locked acquisitions and to use ensemble average procedures. Thereby, it was possible to measure the temporal and spatial evolution of the disturbances introduced in the flow. In addition, phase-locked measurements of the velocity field in the liquid layer were performed using standard planar Particle Image Velocimetry (PIV). The velocity fields were extracted at a fixed streamwise location, whereas the measurements of the liquid level were performed at several locations along the pipe. The assessment of the setup was important for validation of the methodology proposed in this work, since it aimed at providing results for further comparisons with theoretical models and numerical simulations. Therefore, the work focuses on validation and characterization of interfacial waves within the linear regime. Results show that under controlled conditions, the wave development can be well captured and reproduced. In addition, linear waves were observed for liquid level oscillations lower than about 1.5% of the pipe diameter. It was not possible to accurately define an amplitude threshold for the appearance of nonlinear effects because it strongly depended on the wave frequency. According to the experimental findings, longer waves display characteristics similar to linear waves, while short ones exhibit a more complex evolution, even for low amplitudes.

  7. Modeling study on the flow patterns of gas-liquid flow for fast decarburization during the RH process

    Science.gov (United States)

    Li, Yi-hong; Bao, Yan-ping; Wang, Rui; Ma, Li-feng; Liu, Jian-sheng

    2018-02-01

    A water model and a high-speed video camera were utilized in the 300-t RH equipment to study the effect of steel flow patterns in a vacuum chamber on fast decarburization and a superior flow-pattern map was obtained during the practical RH process. There are three flow patterns with different bubbling characteristics and steel surface states in the vacuum chamber: boiling pattern (BP), transition pattern (TP), and wave pattern (WP). The effect of the liquid-steel level and the residence time of the steel in the chamber on flow patterns and decarburization reaction were investigated, respectively. The liquid-steel level significantly affected the flow-pattern transition from BP to WP, and the residence time and reaction area were crucial to evaluate the whole decarburization process rather than the circulation flow rate and mixing time. A superior flow-pattern map during the practical RH process showed that the steel flow pattern changed from BP to TP quickly, and then remained as TP until the end of decarburization.

  8. Studying the instantaneous velocity field in gas-sheared liquid films in a horizontal duct

    Science.gov (United States)

    Vasques, Joao; Tokarev, Mikhail; Cherdantsev, Andrey; Hann, David; Hewakandamby, Buddhika; Azzopardi, Barry

    2016-11-01

    In annular flow, the experimental validation of the basic assumptions on the liquid velocity profile is vital for developing theoretical models of the flow. However, the study of local velocity of liquid in gas-sheared films has proven to be a challenging task due to the highly curved and disturbed moving interface of the phases, small scale of the area of interrogation, high velocity gradients and irregular character of the flow. This study reports on different optical configurations and interface-tracking methods employed in a horizontal duct in order to obtain high-resolution particle image velocimetry (PIV) data in such types of complex flows. The experimental envelope includes successful measurements in 2D and 3D waves regimes, up to the disturbance wave regime. Preliminary data show the presence of complex structures in the liquid phase, which includes re-circulation areas below the liquid interface due to the gas-shearing action, together with non-uniform transverse movements of the liquid phase close to the wall due to the presence of 3D waves at the interface. With the aid of the moving interface-tracking, PIV, time-resolved particle-tracking velocimetry and vorticity measurements were performed.

  9. Effect of Gas- and Liquid-injection Methods on Formation of Bubble and Liquid Slug at Merging Micro T-junction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jun Kyoung [Kyungnam Univ., Changwon (Korea, Republic of); Lee, Chi Young [Pukyong Nat’l Univ., Busan (Korea, Republic of)

    2016-04-15

    In the present experimental study, the effect of gas- and liquid-injected methods on the formation of bubble and liquid slug at the merging micro T-junction of a square microchannel with dimensions 600 μm × 600 μm was investigated. Nitrogen and water were used as test fluids. The superficial velocities of the liquid and gas were in the range of 0.05 - 1 m/s, and 0.1 - 1 m/s, respectively, where the Taylor flow was observed. The bubble length, liquid slug length, bubble velocity, and bubble generation frequency were measured by analyzing the images captured using a high-speed camera. Under similar inlet superficial velocity conditions, in the case of gas injection to the main channel at the merging T-junction (T{sub g}as-liquid), the lengths of the bubble and liquid slug were longer, and the bubble generation frequency was lower than in the case of liquid injection to the main channel at the merging T-junction (T{sub l}iquid-gas). On the other hand, in both cases, the bubble velocity was almost the same. The previous correlation proposed using experimental data for T{sub l}iquid-gas had predicted the present experimental data of bubble length, bubble velocity, liquid slug length, and bubble generation frequency for T{sub g}as-liquid to be ~24%, ~9%, ~39%, ~55%, respectively.

  10. Formation of a vortex flow at the laser cutting of sheet metal with low pressure of assisting gas

    Energy Technology Data Exchange (ETDEWEB)

    Kovalev, O B; Yudin, P V; Zaitsev, A V [Khristianovich' s Institute of Theoretical and Applied Mechanics, Russian Academy of Sciences, Siberian Branch, Novosibirsk (Russian Federation)], E-mail: kovalev@itam.nsc.ru

    2008-08-07

    Specific features of subsonic jet gas flows in narrow channels geometrically similar to the laser cut are studied experimentally and theoretically. Such flows are visualized by a technique based on prior application of a viscous liquid film onto the side walls of the channel made of transparent glass. The gas flow inside the channel induces a liquid flow on the glass wall in the form of extremely small filaments, which coincide with the streamlines of the gas flow. Filming of these filaments by a CCD camera allows one to capture the specific features of these gas-dynamic flows. Mathematical modelling of the dynamics of a viscous compressible heat-conducting gas was performed by solving full three-dimensional Navier-Stokes equations. Numerical calculations and experiments reveal vortex structures in the flow at the entrance and exit of the channel, which may directly affect the surface quality in real gas-laser cutting of metals. The largest vortex, which arises at the channel exit, collects and accumulates the liquid flowing down the channel walls. Jet flows are generated by sonic nozzles with conical or cylindrical exit sections or by a double coaxial nozzle. The double nozzle includes the central conical nozzle and the side concentric nozzle, which allows additional side injection of the gas to be organized. The study with the double nozzle shows that the vortices disappear as the pressure in the external nozzle is increased, and a stable vortex-free attached gas flow is formed.

  11. Design and Development of Gas-Liquid Cylindrical Cyclone Compact Separators for Three-Phase Flow; SEMIANNUAL

    International Nuclear Information System (INIS)

    Mohan, Ram S.; Shoham, Ovadia

    1999-01-01

    The objective of this five-year project (October, 1997-September, 2002) is to expand the current research activities of Tulsa University Separation Technology Projects (TUSTP) to multiphase oil/water/gas separation. This project will be executed in two phases. Phase I (1997-2000) will focus on the investigations of the complex multiphase hydrodynamic flow behavior in a three-phase Gas-Liquid Cylindrical Cyclone (GLCC) Separator. The activities of this phase will include the development of a mechanistic model, a computational fluid dynamics (CFD) simulator, and detailed experimentation on the three-phase GLCC. The experimental and CFD simulation results will be suitably integrated with the mechanistic model. In Phase II (2000-2002), the developed GLCC separator will be tested under high pressure and real crudes conditions. This is crucial for validating the GLCC design for field application and facilitating easy and rapid technology deployment. Design criteria for industrial applications will be developed based on these results and will be incorporated into the mechanistic model by TUSTP

  12. Liquid-Flow Controller With Trickle Preflow

    Science.gov (United States)

    Cox, George B., Jr.

    1990-01-01

    Liquid-flow controller allows pressure in liquid to increase steeply with flow as flow starts, then provides more-gradual nearly linear rise of pressure with flow as flow and pressure increase beyond preset breakpoint. Controller alternative version of mechanism described in "Liquid-Flow Controller Responds To Pressure" (MFS-28329) and "Liquid-Flow Controller With Preset Break Pressure" (MFS-28330). Material cut out of cone at tip of pintle. Liquid always passes from shell, albeit at low rate. When pressure in shell great enough to force orifice away from pintle, liquid flows at greater rate.

  13. Gas microstrip detectors for X-ray tomographic flow imaging

    CERN Document Server

    Key, M J; Luggar, R D; Kundu, A

    2003-01-01

    A investigation into the suitability of gas microstrip detector technology for a high-speed industrial X-ray tomography system is reported. X-ray energies in the region 20-30 keV are well suited to the application, which involves imaging two-dimensional slices through gas/liquid multiphase pipeline flows for quantitative component fraction measurement. Stable operation over a period representing several hundred individual tomographic scans at gas gains of 500 is demonstrated using a Penning gas mixture of krypton/propylene.

  14. Development of gas-liquid two-phase flow measurement technique in narrow channel. Application of micro wire-mesh sensor to the flow between parallel plates

    International Nuclear Information System (INIS)

    Ito, Daisuke; Kikura, Hiroshige; Aritomi, Masanori

    2009-01-01

    A novel two-phase flow measuring technique based on local electrical conductivity measurement was developed for clarifications of three-dimensional flow structure in gas-liquid two-phase flow in a narrow channel. The measuring method applies the principle of conventional wire-mesh tomography, which can measure the instantaneous void fraction distributions in a cross-section of a flow channel. In this technique, the electrodes are fixed on the inside of the walls facing each other, and the local void fractions were obtained by the electrical conductivity measurement between electrodes arranged on each wall. Therefore, the flow structure and the bubble behavior can be investigated by three-dimensional void fraction distributions in the channel with narrow gap. In this paper, a micro Wire-Mesh Sensor (μWMS) which has the gap of 3 mm was developed, and the instantaneous void fraction distributions were measured. From the measured distributions, three-dimensional bubble distributions were reconstructed, and bubble volumes and bubble velocities were estimated. (author)

  15. Numerical study on modeling of liquid film flow under countercurrent flow limitation in volume of fluid method

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Taro, E-mail: watanabe_t@qe.see.eng.osaka-u.ac.jp [Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita-shi, Osaka 565-7895 (Japan); Takata, Takashi, E-mail: takata.takashi@jaea.go.jp [Japan Atomic Energy Agency, 4002 Narita-chou, Oarai-machi, Higashi-Ibaraki-gun, Ibaraki 331-1393 (Japan); Yamaguchi, Akira, E-mail: yamaguchi@n.t.u-tokyo.ac.jp [Graduate School of Engineering, The University of Tokyo, 2-22 Shirakata-Shirane, Tokai-mura, Naka-gun, Ibaraki 319-1188 (Japan)

    2017-03-15

    Highlights: • Thin liquid film flow under CCFL was modeled and coupled with the VOF method. • The difference of the liquid flow rate in experiments of CCFL was evaluated. • The proposed VOF method can quantitatively predict CCFL with low computational cost. - Abstract: Countercurrent flow limitation (CCFL) in a heat transfer tube at a steam generator (SG) of pressurized water reactor (PWR) is one of the important issues on the core cooling under a loss of coolant accident (LOCA). In order to improve the prediction accuracy of the CCFL characteristics in numerical simulations using the volume of fluid (VOF) method with less computational cost, a thin liquid film flow in a countercurrent flow is modeled independently and is coupled with the VOF method. The CCFL characteristics is evaluated analytically in condition of a maximizing down-flow rate as a function of a void fraction or a liquid film thickness considering a critical thickness. Then, we have carried out numerical simulations of a countercurrent flow in a vertical tube so as to investigate the CCFL characteristics and compare them with the previous experimental results. As a result, it has been concluded that the effect of liquid film entrainment by upward gas flux will cause the difference in the experiments.

  16. PIV Measurement of Transient 3-D (Liquid and Gas Phases) Flow Structures Created by a Spreading Flame over 1-Propanol

    Science.gov (United States)

    Hassan, M. I.; Kuwana, K.; Saito, K.

    2001-01-01

    In the past, we measured three-D flow structure in the liquid and gas phases that were created by a spreading flame over liquid fuels. In that effort, we employed several different techniques including our original laser sheet particle tracking (LSPT) technique, which is capable of measuring transient 2-D flow structures. Recently we obtained a state-of-the-art integrated particle image velocimetry (IPIV), whose function is similar to LSPT, but it has an integrated data recording and processing system. To evaluate the accuracy of our IPIV system, we conducted a series of flame spread tests using the same experimental apparatus that we used in our previous flame spread studies and obtained a series of 2-D flow profiles corresponding to our previous LSPT measurements. We confirmed that both LSPT and IPIV techniques produced similar data, but IPIV data contains more detailed flow structures than LSPT data. Here we present some of newly obtained IPIV flow structure data, and discuss the role of gravity in the flame-induced flow structures. Note that the application of IPIV to our flame spread problems is not straightforward, and it required several preliminary tests for its accuracy including this IPIV comparison to LSPT.

  17. Aerospace gas/liquid separator for terrestrial applications

    International Nuclear Information System (INIS)

    Mondt, J.F.

    1996-01-01

    The space gas/liquid separator, a key component in the heat transport subsystem of a space reactor power system, was developed to remove helium gas from liquid lithium in zero gravity. Helium is generated from lithium irradiation in the reactor core and would reach saturation in lithium after 48 hours of full power operations. The gas/liquid separator is also applicable for large commercial powerplants to deaerate the water before and after the feedwater heaters. Another terrestrial application is for industrial companies to use the gas/liquid separator and wet chemistry to remove all the gases from the air and only discharge clean air to the atmosphere. An additional application that resulted from this gas/liquid separator technology, was separating liquid carbon dioxide from nitrogen. This application is opposite from the space application in that it is removing a liquid from a gas rather than a gas from a liquid

  18. Numerical simulation of the gas-liquid interaction of a liquid jet in supersonic crossflow

    Science.gov (United States)

    Li, Peibo; Wang, Zhenguo; Sun, Mingbo; Wang, Hongbo

    2017-05-01

    The gas-liquid interaction process of a liquid jet in supersonic crossflow with a Mach number of 1.94 was investigated numerically using the Eulerian-Lagrangian method. The KH (Kelvin-Helmholtz) breakup model was used to calculate the droplet stripping process, and the secondary breakup process was simulated by the competition of RT (Rayleigh-Taylor) breakup model and TAB (Taylor Analogy Breakup) model. A correction of drag coefficient was proposed by considering the compressible effects and the deformation of droplets. The location and velocity models of child droplets after breakup were improved according to droplet deformation. It was found that the calculated spray features, including spray penetration, droplet size distribution and droplet velocity profile agree reasonably well with the experiment. Numerical results revealed that the streamlines of air flow could intersect with the trajectory of droplets and are deflected towards the near-wall region after they enter into spray zone around the central plane. The analysis of gas-liquid relative velocity and droplet deformation suggested that the breakup of droplets mainly occurs around the front region of the spray where gathered a large number of droplets with different sizes. The liquid trailing phenomenon of jet spray which has been discovered by the previous experiment was successfully captured, and a reasonable explanation was given based on the analysis of gas-liquid interaction process.

  19. Non-invasive classification of gas-liquid two-phase horizontal flow regimes using an ultrasonic Doppler sensor and a neural network

    Science.gov (United States)

    Musa Abbagoni, Baba; Yeung, Hoi

    2016-08-01

    The identification of flow pattern is a key issue in multiphase flow which is encountered in the petrochemical industry. It is difficult to identify the gas-liquid flow regimes objectively with the gas-liquid two-phase flow. This paper presents the feasibility of a clamp-on instrument for an objective flow regime classification of two-phase flow using an ultrasonic Doppler sensor and an artificial neural network, which records and processes the ultrasonic signals reflected from the two-phase flow. Experimental data is obtained on a horizontal test rig with a total pipe length of 21 m and 5.08 cm internal diameter carrying air-water two-phase flow under slug, elongated bubble, stratified-wavy and, stratified flow regimes. Multilayer perceptron neural networks (MLPNNs) are used to develop the classification model. The classifier requires features as an input which is representative of the signals. Ultrasound signal features are extracted by applying both power spectral density (PSD) and discrete wavelet transform (DWT) methods to the flow signals. A classification scheme of ‘1-of-C coding method for classification’ was adopted to classify features extracted into one of four flow regime categories. To improve the performance of the flow regime classifier network, a second level neural network was incorporated by using the output of a first level networks feature as an input feature. The addition of the two network models provided a combined neural network model which has achieved a higher accuracy than single neural network models. Classification accuracies are evaluated in the form of both the PSD and DWT features. The success rates of the two models are: (1) using PSD features, the classifier missed 3 datasets out of 24 test datasets of the classification and scored 87.5% accuracy; (2) with the DWT features, the network misclassified only one data point and it was able to classify the flow patterns up to 95.8% accuracy. This approach has demonstrated the

  20. Dual liquid and gas chromatograph system

    Science.gov (United States)

    Gay, D.D.

    A chromatographic system is described that utilizes one detection system for gas chromatographic and micro-liquid chromatographic determinations. The detection system is a direct-current, atmospheric-pressure, helium plasma emission spectrometer. The detector utilizes a nontransparent plasma source unit which contains the plasma region and two side-arms which receive effluents from the micro-liquid chromatograph and the gas chromatograph. The dual nature of this chromatographic system offers: (1) extreme flexibility in the samples to be examined; (2) extreme low sensitivity; (3) element selectivity; (4) long-term stability; (5) direct correlation of data from the liquid and gas samples; (6) simpler operation than with individual liquid and gas chromatographs, each with different detection systems; and (7) cheaper than a commercial liquid chromatograph and a gas chromatograph.

  1. Drag reduction by polymer addition in single and two-phase gas-liquid flows in pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Bizotto, Vanessa Cristina; Paes, Diogo Melo; Franca, Fernando de Almeida [Universidade Estadual de Campinas, SP (Brazil). Centro de Estudos de Petroleo. LabPetro]. E-mails: vanessa@cepetro.unicamp.br; diogopaes10@hotmail.com; Sabadini, Edvaldo [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica]. E-mails: sabadini@iqm.unicamp.br; ffranca@fem.unicamp.br

    2008-07-01

    Turbulence mechanisms, as the eddies formation frequency and size, promote energy dissipation that appears as pressure drop in pipe flows. Adding minute amounts of polymers - ppm - of high molecular weight to the solution can lead to the reduction of the viscous dissipation. The formed macromolecules interact with the eddies, cause the eddies coherence breakdown, damp the energy transport and reduces the pressure drop. This phenomenon is known as the hydrodynamic drag reduction (DR, for short). Thus, for a given pipe flow rate there is decrease in pressure head, which is a desired operating strategy when transporting liquids. Studies on the hydrodynamic drag reduction in polymeric systems have been carried out in collaboration by the Chemistry Institute and the Petroleum Laboratory - LabPetro, UNICAMP. These studies have allowed microscopic approaches to the engineering scales, tackling the most usual processes - single phase flows, as well as gas-liquid two-phase flows in pipelines, which are quite common in the chemical and the petroleum industries. Tests conducted in the Chemistry Institute comprised over-the-bench experimentations made with a rotational double-gap type rheometer. These quick performed tests used small amount of polymers, and provided information on the additive concentration, the drag reduction and the solution mechanical stability along a turbulent shearing process. The results indicated that 17% is the limiting drag reduction achieved when a 2 ppm aqueous solution of polyacrylamide - PAM - was tested. These tests, besides giving preliminary estimations, are limited in terms of engineering application due to the low shearing rates applied by the viscometer. The tests performed at LabPetro comprised pressure drop measurements in actual pipe flows, both water single and air-water two-phase flows, using the previous knowledge acquired with the viscometer tests. In the former case, the Prandtl-von Karman map has been drawn to show the %DR in terms

  2. A development of multiphase flow facility

    International Nuclear Information System (INIS)

    Ismail Mustapha; Jaafar Abdullah

    2004-01-01

    Multiphase liquid flow facility shall be enabling to transport of oil/gas/water in pipelines. In horizontal pipelines, the different flow patterns that could be observed. The flow pattern will depend mainly on the gas and liquid velocities, and gas liquid ratio. For very high liquid velocities and low gas liquid ratios, the dispersed bubble flow is observed. For low flow rates of liquid and gas, a smooth or wavy stratified flow is expected. For intermediate liquid velocities, rolling waves of liquids are formed. The rolling waves increase to the point of forming a plug flow and a slug flow. For very high gas velocities, the annular flow is observed Also include a tillable test section allowing for testing at any angle between 0 0 degree from horizontal, lowering the measurement uncertainties and increased capabilities with respect to flow rates and gas fractions. (Author)

  3. The influence of the reactor pressure on the hydrodynamics in a cocurrent gas-liquid trickle-bed reactor

    NARCIS (Netherlands)

    Wammes, W.J.A.; Westerterp, K.R.

    1990-01-01

    The influence of the reactor pressure on the liquid hold-up in the trickle-flow regime and on the transition between trickle-flow and pulse-flow has been investigated in a trickle-flow column operating up to 6.0 MPa with water, and nitrogen or helium as the gas phase. The effect of the gas velocity

  4. Gas-liquid-liquid three-phase flow pattern and pressure drop in a microfluidic chip : similarities with gas-liquid/liquid-liquid flows

    NARCIS (Netherlands)

    Yue, J.; Rebrov, E.; Schouten, J.C.

    2014-01-01

    We report a three-phase slug flow and parallel-slug flow as two major flow patterns found under the nitrogen-decane-water flow through a glass microfluidic chip which features a long microchannel with a hydraulic diameter of 98 µm connected to a cross-flow mixer. The three-phase slug flow pattern is

  5. Program determines two-phase flow

    International Nuclear Information System (INIS)

    Yamashiro, C.E.; Espiell, L.G.S.; Farina, I.H.

    1986-01-01

    When a mixture of a gas and a liquid flows along a horizontal pipe, it is possible to have up to seven different flow patterns. These flow patterns are: 1. Dispersed. When nearly all the liquid is entrained as spray by the gas; 2. Annular. The liquid forms a film around the inside wall of the pipe, and the gas flows at a high velocity as a central core; 3. Bubble. Bubbles of gas move along at about the same velocity as the liquid; 4. Stratified. The liquid flows along the bottom of the pipe and the gas flows above over a smooth gas-liquid interface; 5. Wave. Is similar to stratified except the interface is disturbed by waves moving in the direction of flow; 6. Slug. Waves are picked up periodically in the form of frothy slugs that move at a much greater velocity than the average liquid velocity; 7. Plug. Alternate plugs of liquid and gas move along the pipe

  6. Economics of gas to liquids manufacture

    International Nuclear Information System (INIS)

    Gradassi, M.J.

    1998-01-01

    The last year has seen a great deal in the literature about the rebirth of gas to liquids processes, most notably, Fischer Tropsch processes. This renewed interest has been brought about by a technology that is said to have been so improved that it is now a commercially attractive option for natural gas monetization. No one single reason can be cited for this positive economic change. Rather, it is the result of several technological improvements that together have cut the capital cost of Fischer-Tropsch gas to liquids projects in half. Among these technological improvements are lower cost syngas preparation and lower cost gas to liquids reactors. This paper examines the economics of Fischer-Tropsch gas to liquids manufacture, using recent literature articles to develop process capital costs, operating expenses, liquid product value parameters, and other economic factors, to paint a general picture of the technology's current economic status. While manufacturing economics are reviewed, the answer to the question of gas to liquids project profitability is left to the individual investor whose economic thresholds must, in the final analysis, be met. 15 refs

  7. Application of Electromagnetic Induction Technique to Measure the Void Fraction in Oil/Gas Two Phase Flow

    Science.gov (United States)

    Wahhab, H. A. Abdul; Aziz, A. R. A.; Al-Kayiem, H. H.; Nasif, M. S.; Reda, M. N.

    2018-03-01

    In this work, electromagnetic induction technique of measuring void fraction in liquid/gas fuel flow was utilized. In order to improve the electric properties of liquid fuel, an iron oxide Fe3O4 nanoparticles at 3% was blended to enhance the liquid fuel magnetization. Experiments have been conducted for a wide range of liquid and gas superficial velocities. From the experimental results, it was realized that there is an existing linear relationship between the void fraction and the measured electromotive force, when induction coils were connected in series for excitation coils, regardless of increase or decrease CNG bubbles distribution in liquid fuel flow. Therefore, it was revealed that the utilized method yielded quite reasonable account for measuring the void fraction, showing good agreement with the other available measurement techniques in the two-phase flow, and also with the published literature of the bubbly flow pattern. From the results of the present investigation, it has been proven that the electromagnetic induction is a feasible technique for the actual measurement of void fraction in a Diesel/CNG fuel flow.

  8. Cellular properties of slug flow in vertical co-current gas-liquid flow: slug-churn transition; Caracteristiques cellulaires du regime a poches en ecoulement gaz-liquide co-courant vertical. Transition vers le regime destructure

    Energy Technology Data Exchange (ETDEWEB)

    Lusseyran, Francois

    1990-12-13

    This research thesis reports the study and description of the structure of a slug flow regime in a co-current vertical cylindrical duct, and the characterization and prediction of its transition towards a slug-churn (de-structured) regime. Flow physical mechanisms highlighted by the measurement of two important dynamics variables (wall friction and thickness of liquid films) are related to hypotheses of cellular models. The author first proposes an overview of slug flow regimes: theoretical steady and one-dimensional analysis, mass assessment equations of cellular models, application to the assessment of the flow rate and of the thickness of the film surrounding the gas slug. In the second part, the author addresses the slug flow regime transition towards the slug-churn regime: assessment of the evolution of flow dynamic properties, use of average wall friction analysis to obtain a relevant transition criterion. The third part presents experimental conditions, and measurement methods: conductometry for thickness measurement, polarography for wall friction measurement, and gas phase detection by using an optic barrier or optic fibres [French] Les ecoulements gaz-liquide en conduite verticale presentent quatre configurations ou regimes d'ecoulement. Ce travail porte sur le regime a poches et sur la transition vers la configuration qui lui succede: le regime destructure (churn flow). Les mesures sont effectuees a 200D du point d'injection du gaz, dans une conduite de 12.2 mm de diametre et pour le couple de fluides eau-azote. Les deux principales grandeurs mesurees en fonction des flux d'entree sont: le frottement parietal instantane (methode electrochimique) et l'epaisseur de film instantanee (methode conductimetrique). Une detection optique simultanee de la presence des phases permet un traitement conditionnel de la base de donnees. Les caracteristiques de la cellule moyenne representative de chaque point de fonctionnement en sont deduites: longueur de la cellule

  9. Continuous fixed-bed gas-phase hydroformylation using supported ionic liquid-phase (SILP) Rh catalysts

    DEFF Research Database (Denmark)

    Riisager, Anders; Wasserscheid, Peter; Van Hal, R.

    2003-01-01

    Continuous flow gas-phase hydroformylation of propene was performed using novel supported ionic liquid-phase (SILP) catalysts containing immobilized Rh complexes of the biphosphine ligand sulfoxantphos in the ionic liquids 1-n-butyl-3-methylimidazolium hexafluorophosphate and halogen-free 1-n-butyl...

  10. Experimental study of interfacial wave on a liquid film in vertical annular flow

    International Nuclear Information System (INIS)

    Hazuku, T.; Fukamachi, N.; Takamasa, T.; Matsumoto, Y.

    2003-01-01

    In this study, a precise database of microscopic interfacial wave-structure for annular flow developing in a vertical pipe was obtained using a new measuring technique with a laser focus displacement meter. Adiabatic upward annular air-water flow experiments were conducted using a 3-m-long, 11- mm-ID pipe. Measurements of interfacial waves were conducted at 21 axial locations, spaced 110 mm apart, in the pipe. The axial distances from the inlet (L) normalized by the pipe diameter (D) varied over L/D = 50 to 250. Data were collected for predetermined gas and liquid flow conditions and for Reynolds numbers ranging from Reg = 31,800 to 98,300 for the gas phase and Ref = 1,050 to 9,430 for the liquid phase. Using this new technique, we obtained such local properties as the minimum thickness, maximum thickness, and passing frequency of the waves. The results revealed that the maximum film thickness and passing frequency of disturbance waves decreased gradually, with some oscillations, as flow developed. The flow development, i.e., decreases of film thickness and passing frequency, existed until the pipe exit, which means that the flow might never reach a fully developed condition. Minimum thickness of the film decreased with flow development and with increasing gas flow rate. These results are discussed, taking into account the buffer layer calculated from Karman's three-layer model. Correlation is proposed for the minimum film thickness obtained in regard to interfacial shear stress and the Reynolds number of the liquid. This correlation expresses the minimum film thickness obtained from the experiment within a 5% deviation

  11. Gas hydrates and clathrates. Flow assurance, environmental and economic perspectives and the Nigerian liquefied natural gas project

    International Nuclear Information System (INIS)

    Gbaruko, B.C.; Igwe, J.C.; Nwokeoma, R.C.; Gbaruko, P.N.

    2007-01-01

    Gas hydrates are nonstoichiometric crystalline compounds that belong to the inclusion group known as clathrates. They occur when water molecules attach themselves together through hydrogen bonding and form cavities which can be occupied by a single gas or volatile liquid molecule. Gas hydrates, asphaltenes and waxes are three major threats to flow assurance that must be well assessed by design team uptime. Gas hydrates are also looked upon as a future energy source and as a potential climate hazard. The purpose of this review is to show the chemistry and mechanism of gas hydrate formation, the problems they pose, especially to flow assurance, their system implications, their environmental and economic perspectives with respect to their prospects as storage and transport alternative to the liquefied natural gas technology. (author)

  12. Well-posed Euler model of shock-induced two-phase flow in bubbly liquid

    Science.gov (United States)

    Tukhvatullina, R. R.; Frolov, S. M.

    2018-03-01

    A well-posed mathematical model of non-isothermal two-phase two-velocity flow of bubbly liquid is proposed. The model is based on the two-phase Euler equations with the introduction of an additional pressure at the gas bubble surface, which ensures the well-posedness of the Cauchy problem for a system of governing equations with homogeneous initial conditions, and the Rayleigh-Plesset equation for radial pulsations of gas bubbles. The applicability conditions of the model are formulated. The model is validated by comparing one-dimensional calculations of shock wave propagation in liquids with gas bubbles with a gas volume fraction of 0.005-0.3 with experimental data. The model is shown to provide satisfactory results for the shock propagation velocity, pressure profiles, and the shock-induced motion of the bubbly liquid column.

  13. Simulation of Water Level Fluctuations in a Hydraulic System Using a Coupled Liquid-Gas Model

    Directory of Open Access Journals (Sweden)

    Chao Wang

    2015-08-01

    Full Text Available A model for simulating vertical water level fluctuations with coupled liquid and gas phases is presented. The Preissmann implicit scheme is used to linearize the governing equations for one-dimensional transient flow for both liquid and gas phases, and the linear system is solved using the chasing method. Some classical cases for single liquid and gas phase transients in pipelines and networks are studied to verify that the proposed methods are accurate and reliable. The implicit scheme is extended using a dynamic mesh to simulate the water level fluctuations in a U-tube and an open surge tank without consideration of the gas phase. Methods of coupling liquid and gas phases are presented and used for studying the transient process and interaction between the phases, for gas phase limited in a chamber and gas phase transported in a pipeline. In particular, two other simplified models, one neglecting the effect of the gas phase on the liquid phase and the other one coupling the liquid and gas phases asynchronously, are proposed. The numerical results indicate that the asynchronous model performs better, and are finally applied to a hydropower station with surge tanks and air shafts to simulate the water level fluctuations and air speed.

  14. Features of reducing the turbulent friction of a liquid on the channel wall by gas-saturation

    Directory of Open Access Journals (Sweden)

    Evseev Aleksei

    2017-01-01

    Full Text Available The report presents the results of an experimental study of the efficiency of reducing the local friction at gas saturation of the turbulent boundary layer (TBL in the input section of the channel at different gravitational orientation of the wall, and its dependence on the structure of gas-liquid flow. Profiles of gas concentration have a peak near the wall, which increases with the gas flow increase. The growth of concentration in the near-wall zone leads to rapid coalescence of bubbles, as a result of which the flow in TBL transits to the film-bubble regime with increasing the buoyancy effect of the gas phase, especially at low flow rates. It is shown that the key parameter of friction reduction by gas saturation is the gas phase concentration in the inner region of the boundary layer, whose magnitude is determined by the gas flow rate, the flow velocity, the distance downstream behind the gas generator, and the gravitational orientation of the wall.

  15. Static gas-liquid interfacial direct current discharge plasmas using ionic liquid cathode

    International Nuclear Information System (INIS)

    Kaneko, T.; Baba, K.; Hatakeyama, R.

    2009-01-01

    Due to the unique properties of ionic liquids such as their extremely low vapor pressure and high heat capacity, we have succeeded in creating the static and stable gas (plasmas)-liquid (ionic liquids) interfacial field using a direct current discharge under a low gas pressure condition. It is clarified that the ionic liquid works as a nonmetal liquid electrode, and furthermore, a secondary electron emission coefficient of the ionic liquid is larger than that of conventional metal electrodes. The plasma potential structure of the gas-liquid interfacial region, and resultant interactions between the plasma and the ionic liquid are revealed by changing a polarity of the electrode in the ionic liquid. By utilizing the ionic liquid as a cathode electrode, the positive ions in the plasma region are found to be irradiated to the ionic liquid. This ion irradiation causes physical and chemical reactions at the gas-liquid interfacial region without the vaporization of the ionic liquid.

  16. Void fraction development in gas-liquid flow after a U-bend in a vertically upwards serpentine-configuration large-diameter pipe

    Science.gov (United States)

    Almabrok, Almabrok A.; Aliyu, Aliyu M.; Baba, Yahaya D.; Lao, Liyun; Yeung, Hoi

    2018-01-01

    We investigate the effect of a return U-bend on flow behaviour in the vertical upward section of a large-diameter pipe. A wire mesh sensor was employed to study the void fraction distributions at axial distances of 5, 28 and 47 pipe diameters after the upstream bottom bend. The study found that, the bottom bend has considerable impacts on up-flow behaviour. In all conditions, centrifugal action causes appreciable misdistribution in the adjacent straight section. Plots from WMS measurements show that flow asymmetry significantly reduces along the axis at L/D = 47. Regime maps generated from three axial locations showed that, in addition to bubbly, intermittent and annular flows, oscillatory flow occurred particularly when gas and liquid flow rates were relatively low. At this position, mean void fractions were in agreement with those from other large-pipe studies, and comparisons were made with existing void fraction correlations. Among the correlations surveyed, drift flux-type correlations were found to give the best predictive results.

  17. Fast wire-mesh sensors for gas-liquid flows - Visualisation with up to 10 000 frames per second

    International Nuclear Information System (INIS)

    Prasser, H.M.; Zschau, J.; Peters, D.; Pietzsch, G.; Taubert, W.; Trepte, M.

    2002-01-01

    A wire-mesh sensor developed by the Forschungszentrum Rossendorf produces sequences of instantaneous gas fraction distributions in a cross section at a rate of up to 10 000 frames per second and a spatial resolution of about 2-3 mm. This sensor was applied to an upwards air-liquid flow in a vertical pipe of 51.2 mm diameter. After a brief introduction of the functioning of the sensor, the paper presents results obtained in a at vertical pipe operated with an air-water mixture. Two wire-mesh sensors with a measuring matrix of 24 x 24 points (resolution 2 mm) were placed in a small axial distance behind each other. They were used to study the flow structure in the transition region from bubble to slug flow at an imaging frequency of 2 500 Hz. The two available measuring planes allowed to obtain velocity profiles of the gaseous phase. A sensor with 16 x 16 points (resolution 3 mm) was applied to visualize the transition from bubbly via churn turbulent to annular flow with 10 000 frames per second. In the churn flow region, periodic plug-like structures were found. In the annular flow the sensor is able to resolve wispy structures. (authors)

  18. Cumulative Distributions and Flow Structure of Two-Passage Shear Coaxial Injector with Various Gas Injection Ratio

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Inchul; Kim, Dohun; Koo, Jaye [Korea Aerospace Univ., Goyang (Korea, Republic of)

    2013-07-15

    To verify the effect of inner- and outer-stage gas jets, a shear coaxial injector was designed to analyze the axial velocity profile and breakup phenomenon with an increase in the measurement distance. When the measurement position was increased to Z/d=100, the axial flow showed a fully developed shape due to the momentum transfer, aerodynamic drag effect, and viscous mixing. An inner gas injection, which induces a higher momentum flux ratio near the nozzle, produces the greater shear force on atomization than an outer gas injection. Inner- and Outer-stage gas injection do not affect the mixing between the inner and outer gas flow below Z/d=5. The experiment results showed that the main effect of liquid jet breakup was governed by the gas jet of an inner stage. As the nozzle exit of the outer-stage was located far from the liquid column, shear force and turbulence breaking up of the liquid jets do not fully affect the liquid column. In the case of an inner-stage gas injection momentum flux ratio within 0.84, with the increase in the outer gas momentum flux ratio, the Smd decreases. However, at an inner-stage gas jet momentum flux ratio over 1.38, the Smd shows the similar distribution.

  19. Studying gas-sheared liquid film in horizontal rectangular duct with laser-induced fluorescence technique

    Science.gov (United States)

    Cherdantsev, Andrey; Hann, David; Azzopardi, Barry

    2013-11-01

    High-speed LIF-technique is applied to study gas-sheared liquid film in horizontal rectangular duct with 161 mm width. Instantaneous distributions of film thickness resolved in both longitudinal and transverse coordinates were obtained with a frequency of 10 kHz and spatial resolution from 0.125 mm to 0.04 mm. Processes of generation of fast and slow ripples by disturbance waves are the same as described in literature for downwards annular pipe flow. Disturbance waves are often localized by transverse coordinate and may have curved or slanted fronts. Fast ripples, covering disturbance waves, are typically horseshoe-shaped and placed in staggered order. Their characteristic transverse size is of order 1 cm and it decreases with gas velocity. Entrainment of liquid from film surface can also be visualized. Mechanisms of ripple disruption, known as ``bag break-up'' and ``ligament break-up,'' were observed. Both mechanisms may occur on the same disturbance waves. Various scenarios of droplet deposition on the liquid film are observed, including the impact, slow sinking and bouncing, characterized by different outcome of secondary droplets or entrapped bubbles. Number and size of bubbles increase greatly inside the disturbance waves. Both quantities increase with gas and liquid flow rates. EPSRC Programme Grant MEMPHIS (EP/K003976/1), and Roll-Royce UTC (Nottingham, for access to flow facility).

  20. Liquid metal Flow Meter - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, C.; Hoogendoom, S.; Hudson, B.; Prince, J.; Teichert, K.; Wood, J.; Chase, K.

    2007-01-30

    Measuring the flow of liquid metal presents serious challenges. Current commercially-available flow meters use ultrasonic, electromagnetic, and other technologies to measure flow, but are inadequate for liquid metal flow measurement because of the high temperatures required by most liquid metals. As a result of the reactivity and high temperatures of most liquid metals, corrosion and leakage become very serious safety concerns. The purpose of this project is to develop a flow meter for Lockheed Martin that measures the flow rate of molten metal in a conduit.

  1. Fully integrated microfluidic measurement system for real-time determination of gas and liquid mixtures composition

    NARCIS (Netherlands)

    Lötters, Joost Conrad; Groenesteijn, Jarno; van der Wouden, E.J.; Sparreboom, Wouter; Lammerink, Theodorus S.J.; Wiegerink, Remco J.

    2015-01-01

    We have designed and realised a fully integrated microfluidic measurement system for real-time determination of both flow rate and composition of gas- and liquid mixtures. The system comprises relative permittivity sensors, pressure sensors, a Coriolis flow and density sensor, a thermal flow sensor

  2. Influence of leakage flow on the behaviour of gas behind a blockage in LMFBR subassembly geometry

    International Nuclear Information System (INIS)

    Fukuzawa, Y.

    1980-07-01

    Observations were made of the behaviour of gas behind a uniform porous 21% corner blockage within a pin-bundle of LMFBR subassembly geometry. The main parameter of the experiment was the leakage flow rate through the blockage. The behaviour of gas is significantly influenced by the leakage flow rate. The measured size and residence time of a gas cavity formed behind the blockage are shown and the mechanisms of the gas cavity dispersion by the leakage flow discussed by using a simple model of the liquid flow distribution behind the blockage. (orig.) [de

  3. Influence of the Fin on Two-Dimensional Characteristics of Dispersed Flow With Wall Liquid Film in the Vicinity of Obstacle

    International Nuclear Information System (INIS)

    Stosic, Zoran V.; Stevanovic, Vladimir D.; Serizawa, Akimi

    2002-01-01

    Spacers have positive effects on the heat transfer enhancement and critical heat flux (CHF) increase downstream of their location in the boiling channel. These effects are further increased by the inclusion of the fin on the spacer rear edge. Numerical simulation of a separation in a high void gas phase and dispersed droplets flow around a spacer, with a liquid film flowing on the wall, is performed. Mechanisms leading to the CHF increase due to the two-phase flow separation and liquid film thickening downstream the spacer are demonstrated. Numerical simulations of gas phase, entrained droplets and wall liquid film flows were performed with the three-fluid model and with the application of the high order numerical scheme for the liquid film surface interface tracking. Predicted is a separation of gas and entrained droplets streams around the spacer without and with a fin inclined 30 and 60 degrees to the wall, as well as a change of wall liquid film thickness in the vicinity of spacer. Results of liquid film dynamic behaviour are compared with the recently obtained experimental results. Multi-dimensional characteristics of surface waves on the liquid film were measured with newly developed ultrasonic transmission technique in a 3 3 rod bundle test section with air-water flow under atmospheric conditions. Obtained numerical results are in good agreement with experimental observations. The presented investigation gives insight into the complex mechanisms of separated two-phase flow with wall liquid film around the spacer and support thermal-hydraulic design and optimisation of flow obstacles in various thermal equipment. (authors)

  4. Gas-liquid contacting in mixing vessels

    International Nuclear Information System (INIS)

    Mann, R.

    1983-01-01

    This report by Dr. R. Mann of UMIST presents a critical survey of literature on the contacting of gases with liquids in stirred vessels. Research undertaken in the last fifteen years in analysed, and promising areas for future research are identified. The report deals with physical contacting, mass transfer between the gas and liquid phases and the utilisation of the stirred vessel as a gas-liquid reactor. Three sections are given on gas-liquid contacting: physical aspects; interphase mass transfer; and chemical reactions. It also discusses recent new approaches and includes a summary of conclusions, nomenclature and references

  5. Dual-phase gas-permeation flow-injection thermometric analysis for the determination of carbon dioxide.

    Science.gov (United States)

    Liu, S J; Tubino, M

    1998-11-01

    A flow-injection configuration based on a dual-phase gas-permeation system from a liquid donor to a gas acceptor stream with a thermistor flow-through detector is proposed for the direct analysis of the gas in the acceptor. This system was applied for the determination of carbon dioxide (in the form of carbonate) using the following chemical reaction: CO(2)(g)+2NH(3)(g)+H(2)O(g)=(NH(4))(2)CO(3)(s), with a linear response from 1x10(-3) to 50x10(-3) mol l(-1) of CO(3)(2-). Carbon dioxide was produced in the liquid donor and permeated into the gaseous acceptor stream of air/water vapor. The detection limit is 1x10(-3) mol l(-1) of carbonate, and a sampling frequency of 60 h(-1) is achieved with a relative standard deviation of 4.1% for replicate injections. The dual-phase gas-permeation flow-injection manifold, along with the membrane and phase separations, as well as the chemical reaction, provides enhanced selectivity when compared with the system employing a liquid acceptor stream, as serious interferents in this system, for instance, acetate and formate, among others, do not interfere in the proposed system.

  6. Numerical modelling of multiphase liquid-vapor-gas flows with interfaces and cavitation

    Science.gov (United States)

    Pelanti, Marica

    2017-11-01

    We are interested in the simulation of multiphase flows where the dynamical appearance of vapor cavities and evaporation fronts in a liquid is coupled to the dynamics of a third non-condensable gaseous phase. We describe these flows by a single-velocity three-phase compressible flow model composed of the phasic mass and total energy equations, the volume fraction equations, and the mixture momentum equation. The model includes stiff mechanical and thermal relaxation source terms for all the phases, and chemical relaxation terms to describe mass transfer between the liquid and vapor phases of the species that may undergo transition. The flow equations are solved by a mixture-energy-consistent finite volume wave propagation scheme, combined with simple and robust procedures for the treatment of the stiff relaxation terms. An analytical study of the characteristic wave speeds of the hierarchy of relaxed models associated to the parent model system is also presented. We show several numerical experiments, including two-dimensional simulations of underwater explosive phenomena where highly pressurized gases trigger cavitation processes close to a rigid surface or to a free surface. This work was supported by the French Government Grant DGA N. 2012.60.0011.00.470.75.01, and partially by the Norwegian Grant RCN N. 234126/E30.

  7. PDBD with continuous liquids flows in a discharge reactor

    International Nuclear Information System (INIS)

    Rodríguez-Méndez, B G; Gutiérrez-León, D G; López-Callejas, R; Valencia-Alvarado, R; Muñoz-Castro, A E; Mercado-Cabrera, A; Peña-Eguiluz, R; Belman-Flores, J M; De la Piedad-Beneitez, A

    2015-01-01

    This paper presents the design, construction and testing of a cylindrical pulsed dielectric barrier discharge (PDBD) reactor aimed to microbiological elimination of Escherichia coli ATCC 8739 bacteria. In the reactor, water flowed continuously and to countercurrent an oxygen gas was injected. The water pumping was carried out with a peristaltic pump type, stainless steel and aluminum constructed, and water was recirculated through norprene tubing. The considered parameters in order to promote energetic efficiency were: the residence time of the water contaminated with bacteria, flow rate of the liquid, shape and material used to build electrodes and dielectric, pressure, and gas injection flow rate. The pulsed power supply parameters are featured by 25-30 kV high voltage, 500 Hz frequency and 30 μs width. The outcome elimination of E. coli bacteria at 10 3 , 10 4 and 10 6 CFU/mL concentrations reached an efficiency over 0.5 log-order in absence of oxygen; while >2 log-orders when oxygen gas was injected during the process. (paper)

  8. Numerical Study on Flow, Temperature, and Concentration Distribution Features of Combined Gas and Bottom-Electromagnetic Stirring in a Ladle

    Directory of Open Access Journals (Sweden)

    Yang Li

    2018-01-01

    Full Text Available A novel method of combined argon gas stirring and bottom-rotating electromagnetic stirring in a ladle refining process is presented in this report. A three-dimensional numerical model was adopted to investigate its effect on improving flow field, eliminating temperature stratification, and homogenizing concentration distribution. The results show that the electromagnetic force has a tendency to spiral by spinning clockwise on the horizontal section and straight up along the vertical section, respectively. When the electromagnetic force is applied to the gas-liquid two phase flow, the gas-liquid plume is shifted and the gas-liquid two phase region is extended. The rotated flow driven by the electromagnetic force promotes the scatter of bubbles. The temperature stratification tends to be alleviated due to the effect of heat compensation and the improved flow. The temperature stratification tends to disappear when the current reaches 1200 A. The improved flow field has a positive influence on decreasing concentration stratification and shortening the mixing time when the combined method is imposed. However, the alloy depositing site needs to be optimized according to the whole circulatory flow and the region of bubbles to escape.

  9. FLIT: Flowing LIquid metal Torus

    Science.gov (United States)

    Kolemen, Egemen; Majeski, Richard; Maingi, Rajesh; Hvasta, Michael

    2017-10-01

    The design and construction of FLIT, Flowing LIquid Torus, at PPPL is presented. FLIT focuses on a liquid metal divertor system suitable for implementation and testing in present-day fusion systems, such as NSTX-U. It is designed as a proof-of-concept fast-flowing liquid metal divertor that can handle heat flux of 10 MW/m2 without an additional cooling system. The 72 cm wide by 107 cm tall torus system consisting of 12 rectangular coils that give 1 Tesla magnetic field in the center and it can operate for greater than 10 seconds at this field. Initially, 30 gallons Galinstan (Ga-In-Sn) will be recirculated using 6 jxB pumps and flow velocities of up to 10 m/s will be achieved on the fully annular divertor plate. FLIT is designed as a flexible machine that will allow experimental testing of various liquid metal injection techniques, study of flow instabilities, and their control in order to prove the feasibility of liquid metal divertor concept for fusion reactors. FLIT: Flowing LIquid metal Torus. This work is supported by the US DOE Contract No. DE-AC02-09CH11466.

  10. Heat transfer by liquids in suspension in a turbulent gas stream (1960); Transfert de chaleur par liquides entraines dans un ecoulement gazeux turbulent (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Grison, E [Commissariat a l' Energie Atomique, Lab. de Physique-Chimie et basses temperatures, Grenoble (France).Centre d' Etudes Nucleaires; Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The introduction of a small volume of liquid into a turbulent gas stream used as cooling agent improves considerably the heat transfer coefficient of the gas. When the turbulent regime is established, one observes in a cylindrical tube two types of flow whether the liquid wets or does not wet the wall. In the first case, one gets on the wall an annular liquid film and droplets in suspension are in the gas stream. In the second case, a fog of droplets is formed without any liquid film on the wall. Experiments were performed with the following mixtures: water-hydrogen, water-nitrogen, ethanol-nitrogen (wetting liquids) introduced into a stainless steel tube of 4 mm ID, electrically heated on 320 mm of length. We varied the gas flow rate (Reynolds until 50000), the rate of the liquid flow rate to gas flow rate (until 15), the pressure (until 10 kg/cm{sup 2}), the temperature (until the boiling point) and the heat flux (until 250 W/cm{sup 2}). Two types of burnout were observed. A formula of correlation of the burnout heat flux is given. Making use of the analogy between mass transfer and heat transfer, a dimensionless formula of correlation of the local heat transfer coefficients is established. (author) [French] L'introduction d'un faible volume de liquide dans un ecoulement gazeux turbulent utilise comme fluide refrigerant permet une amelioration considerable des coefficients d'echanges thermiques que l'on aurait si le gaz etait employe seul (nous avons obtenu un facteur d'amelioration superieur a 10). En regime turbulent etabli, on observe dans un tube deux modes d'ecoulements selon que le liquide mouille ou ne mouille pas la paroi. Dans le premier cas, on obtient sur la paroi un film annulaire liquide et des gouttelettes en suspension dans le coeur gazeux. Dans le deuxieme cas, il se forme un veritable brouillard sans film liquide sur la paroi. Les etudes experimentales ont ete effectuees avec les melanges eau-hydrogene, eau-azote, ethanol-azote (liquides

  11. Partial liquid-penetration inside a deep trench by film flowing over it

    Science.gov (United States)

    Nguyen, Phuc-Khanh; Dimakopoulos, Yiannis; Tsamopoulos, John

    2014-11-01

    Liquid film flow along substrates featuring a deep trench may not wet the trench floor, but create a second gas-liquid interface inside the trench. The liquid penetration inside the trench depends on the location and shape of this inner interface. The penetration increases by decreasing the two three-phase contact lines between the inner interface and the two side-walls or the flow rate and depends on the liquid properties. This partial-penetration is studied by employing the Galerkin / finite element method to solve the two-dimensional steady-state Navier-Stokes equations in a physical domain that is adaptively remeshed. Multiple branches of steady solutions connected via turning points are revealed by pseudo arc-length continuation. Flow hysteresis may occur in a certain range of liquid penetration depth, when the interaction of the two interfaces changes qualitatively. This induces an abrupt jump of penetration distance and deformation amplitude of the outer interface. Work supported by the General Secretariat of Research & Technology of Greece through the program ``Excellence'' (Grant No. 1918) in the framework ``Education and Lifelong Learning'' co-funded by the ESF.

  12. Identification method of gas-liquid two-phase flow regime based on image wavelet packet information entropy and genetic neural network

    International Nuclear Information System (INIS)

    Zhou Yunlong; Chen Fei; Sun Bin

    2008-01-01

    Based on the characteristic that wavelet packet transform image can be decomposed by different scales, a flow regime identification method based on image wavelet packet information entropy feature and genetic neural network was proposed. Gas-liquid two-phase flow images were captured by digital high speed video systems in horizontal pipe. The information entropy feature from transformation coefficients were extracted using image processing techniques and multi-resolution analysis. The genetic neural network was trained using those eigenvectors, which was reduced by the principal component analysis, as flow regime samples, and the flow regime intelligent identification was realized. The test result showed that image wavelet packet information entropy feature could excellently reflect the difference between seven typical flow regimes, and the genetic neural network with genetic algorithm and BP algorithm merits were with the characteristics of fast convergence for simulation and avoidance of local minimum. The recognition possibility of the network could reach up to about 100%, and a new and effective method was presented for on-line flow regime. (authors)

  13. Liquid gating elastomeric porous system with dynamically controllable gas/liquid transport.

    Science.gov (United States)

    Sheng, Zhizhi; Wang, Honglong; Tang, Yongliang; Wang, Miao; Huang, Lizhi; Min, Lingli; Meng, Haiqiang; Chen, Songyue; Jiang, Lei; Hou, Xu

    2018-02-01

    The development of membrane technology is central to fields ranging from resource harvesting to medicine, but the existing designs are unable to handle the complex sorting of multiphase substances required for many systems. Especially, the dynamic multiphase transport and separation under a steady-state applied pressure have great benefits for membrane science, but have not been realized at present. Moreover, the incorporation of precisely dynamic control with avoidance of contamination of membranes remains elusive. We show a versatile strategy for creating elastomeric microporous membrane-based systems that can finely control and dynamically modulate the sorting of a wide range of gases and liquids under a steady-state applied pressure, nearly eliminate fouling, and can be easily applied over many size scales, pressures, and environments. Experiments and theoretical calculation demonstrate the stability of our system and the tunability of the critical pressure. Dynamic transport of gas and liquid can be achieved through our gating interfacial design and the controllable pores' deformation without changing the applied pressure. Therefore, we believe that this system will bring new opportunities for many applications, such as gas-involved chemical reactions, fuel cells, multiphase separation, multiphase flow, multiphase microreactors, colloidal particle synthesis, and sizing nano/microparticles.

  14. Modeling liquid hydrogen cavitating flow with the full cavitation model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.B.; Qiu, L.M.; Qi, H.; Zhang, X.J.; Gan, Z.H. [Institute of Refrigeration and Cryogenic Engineering, Zhejiang University, Hangzhou 310027 (China)

    2008-12-15

    Cavitation is the formation of vapor bubbles within a liquid where flow dynamics cause the local static pressure to drop below the vapor pressure. This paper strives towards developing an effective computational strategy to simulate liquid hydrogen cavitation relevant to liquid rocket propulsion applications. The aims are realized by performing a steady state computational fluid dynamic (CFD) study of liquid hydrogen flow over a 2D hydrofoil and an axisymmetric ogive in Hord's reports with a so-called full cavitation model. The thermodynamic effect was demonstrated with the assumption of thermal equilibrium between the gas phase and liquid phase. Temperature-dependent fluid thermodynamic properties were specified along the saturation line from the ''Gaspak 3.2'' databank. Justifiable agreement between the computed surface pressure, temperature and experimental data of Hord was obtained. Specifically, a global sensitivity analysis is performed to examine the sensitivity of the turbulent computations to the wall grid resolution, wall treatments and changes in model parameters. A proper near-wall model and grid resolution were suggested. The full cavitation model with default model parameters provided solutions with comparable accuracy to sheet cavitation in liquid hydrogen for the two geometries. (author)

  15. US crude oil, natural gas, and natural gas liquids reserves, 1992 annual report

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-18

    This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1992, as well as production volumes for the United States, and selected States and State subdivisions for the year 1992. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), its two major components (nonassociated and associated-dissolved gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, two components of natural gas liquids, lease condensate and natural gas plant liquids, have their reserves and production data presented. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. A discussion of notable oil and gas exploration and development activities during 1992 is provided.

  16. US crude oil, natural gas, and natural gas liquids reserves, 1992 annual report

    International Nuclear Information System (INIS)

    1993-01-01

    This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1992, as well as production volumes for the United States, and selected States and State subdivisions for the year 1992. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), its two major components (nonassociated and associated-dissolved gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, two components of natural gas liquids, lease condensate and natural gas plant liquids, have their reserves and production data presented. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. A discussion of notable oil and gas exploration and development activities during 1992 is provided

  17. Studies on turbulence structure and liquid film behavior in annular two-phase flow flowing in a throat section

    International Nuclear Information System (INIS)

    Yoshida, Kenji; Miyabe, Masaya; Matsumoto, Tadayoshi; Kataoka, Isao; Ohmori, Shuichi; Mori, Michitsugu

    2004-01-01

    Experimental studies on turbulence structure and liquid film behavior in annular two-phase flow were carried out concerned with the steam injector systems for a next-generation nuclear reactor. In the steam injector, steam/water annular two-phase flow is formed at the mixing nozzle. To make an appropriate design for high-performance steam injector system, it is very important to accumulate the fundamental data of thermo-hydro dynamic characteristics of annular flow in the steam injector. Especially, the turbulence modification in multi-phase flow due to the phase interaction is one of the most important phenomena and has attracted research attention. In this study, the liquid film behavior and the resultant turbulence modification due to the phase interaction were investigated. The behavior of the interfacial waves on liquid film flow such as the ripple or disturbance waves were observed to make clear the interfacial velocity and the special structure of the interfacial waves by using the high-speed video camera and the digital camera. The measurements for gas-phase velocity profiles and turbulent intensity in annular flow passing through the throat section were precisely performed to investigate quantitatively the turbulent modification in annular flow by using the constant temperature hot-wire anemometer. The measurements for liquid film thickness by the electrode needle method were also carried out. (author)

  18. Experiments on vertical gas-liquid pipe flows using ultrafast X-ray tomography

    Energy Technology Data Exchange (ETDEWEB)

    Banowski, M.; Beyer, M.; Lucas, D.; Hoppe, D.; Barthel, F. [Helmholtz-Zentrum Dresden-Rossendorf (Germany). Inst. fuer Sicherheitsforschung

    2016-12-15

    For the qualification and validation of two-phase CFD-models for medium and large-scale industrial applications dedicated experiments providing data with high temporal and spatial resolution are required. Fluid dynamic parameter like gas volume fraction, bubble size distribution, velocity or turbulent kinetic energy should be measured locally. Considering the fact, that the used measurement techniques should not affect the flow characteristics, radiation based tomographic methods are the favourite candidate for such measurements. Here the recently developed ultrafast X-ray tomography, is applied to measure the local and temporal gas volume fraction distribution in a vertical pipe. To obtain the required frame rate a rotating X-ray source by a massless electron beam and a static detector ring are used. Experiments on a vertical pipe are well suited for development and validation of closure models for two-phase flows. While vertical pipe flows are axially symmetrically, the boundary conditions are well defined. The evolution of the flow along the pipe can be investigated as well. This report documents the experiments done for co-current upwards and downwards air-water and steam-water flows as well as for counter-current air-water flows. The details of the setup, measuring technique and data evaluation are given. The report also includes a discussion on selected results obtained and on uncertainties.

  19. Measurements of non-reacting and reacting flow fields of a liquid swirl flame burner

    Science.gov (United States)

    Chong, Cheng Tung; Hochgreb, Simone

    2015-03-01

    The understanding of the liquid fuel spray and flow field characteristics inside a combustor is crucial for designing a fuel efficient and low emission device. Characterisation of the flow field of a model gas turbine liquid swirl burner is performed by using a 2-D particle imaging velocimetry(PIV) system. The flow field pattern of an axial flow burner with a fixed swirl intensity is compared under confined and unconfined conditions, i.e., with and without the combustor wall. The effect of temperature on the main swirling air flow is investigated under open and non-reacting conditions. The result shows that axial and radial velocities increase as a result of decreased flow density and increased flow volume. The flow field of the main swirling flow with liquid fuel spray injection is compared to non-spray swirling flow. Introduction of liquid fuel spray changes the swirl air flow field at the burner outlet, where the radial velocity components increase for both open and confined environment. Under reacting condition, the enclosure generates a corner recirculation zone that intensifies the strength of radial velocity. The reverse flow and corner recirculation zone assists in stabilizing the flame by preheating the reactants. The flow field data can be used as validation target for swirl combustion modelling.

  20. Droplet behavior analysis in consideration of droplet entrainment from liquid film in annular dispersed flow

    International Nuclear Information System (INIS)

    Matsuura, Keizo; Otake, Hiroshi; Kataoka, Isao; Serizawa, Akimi

    2000-01-01

    A method of droplet behavior simulation in an annular dispersed flow has been developed. In this method, both droplet deposition and entrainment from liquid film are considered. The Lagrangian method and stochastic model are used to analyze droplet diffusion and deposition behavior in a turbulent flow, and droplet entrainment from liquid film is calculated by an entrainment correlation. For the verification of this method, Gill's experiment is analyzed, in which the transition from annular flow with no entrainment to equilibrium annular dispersed flow was observed. Analysis results can also show the similar transition tendency. The experimental results of radial distribution of droplet mass flux are compared with analysis results. The agreement is good for low liquid flow rate, but entrainment rate must be adjusted for high liquid flow rate, in which gas turbulence is thought to be modified by high droplet density. In future work the effect of high droplet density on turbulence should be considered. (author)

  1. Inverted annular flow experimental study

    International Nuclear Information System (INIS)

    De Jarlais, G.; Ishii, M.

    1985-04-01

    Steady-state inverted annular flow of Freon 113 in up flow was established in a transparent test section. Using a special inlet configuration consisting of long aspect-ratio liquid nozzles coaxially centered within a heated quartz tube, idealized inverted annular flow initial geometry (cylindrical liquid core surrounded by coaxial annulus of gas) could be established. Inlet liquid and gas flowrates, liquid subcooling, and gas density (using various gas species) were measured and varied systematically. The hydrodynamic behavior of the liquid core, and the subsequent downstream break-up of this core into slugs, ligaments and/or droplets of various sizes, was observed. In general, for low inlet liquid velocities it was observed that after the initial formation of roll waves on the liquid core surface, an agitated region of high surface area, with attendant high momentum and energy transfers, occurs. This agitated region appears to propagate downsteam in a quasi-periodic pattern. Increased inlet liquid flow rates, and high gas annulus flow rates tend to diminish the significance of this agitated region. Observed inverted annular flow (and subsequent downstream flow pattern) hydrodynamic behavior is reported, and comparisons are drawn to data generated by previous experimenters studying post-CHF flow

  2. FSU's natural gas liquids business needs investment

    International Nuclear Information System (INIS)

    Plotnikov, V.S.; Berman, M.; Angerinos, G.F.

    1995-01-01

    Production of natural gas liquids has fallen seriously behind its potential in the former Soviet Union (FSU). Restoration of the gas liquids business thus represents a rich investment opportunity. Capital, however, must come from international sources, which remain uncertain about the FSU's legal, commercial, and political systems. If these hurdles can be overcome, FSU output of liquid petroleum gas alone might double between 1990 and 2010. In the FSU, LPG is produced from associated and nonassociated natural gas, condensate, and refinery streams. It also comes from what is known in the FSU as ShFLU--a mixture of propane, butane, pentane, and hexane produced at gas processing plants in Western Siberia and fractionated elsewhere. The paper reviews FSU production of gas liquids focusing on West Siberia, gives a production outlook, and describes LPG use and business development

  3. Comparison of electrical capacitance tomography and gamma densitometer measurement in viscous oil-gas flows

    Energy Technology Data Exchange (ETDEWEB)

    Archibong Eso, A.; Zhao, Yabin; Yeung, Hoi [Department of Offshore Process and Energy Systems Engineering, Cranfield University, Cranfield (United Kingdom)

    2014-04-11

    Multiphase flow is a common occurrence in industries such as nuclear, process, oil and gas, food and chemical. A prior knowledge of its features and characteristics is essential in the design, control and management of such processes due to its complex nature. Electrical Capacitance Tomography (ECT) and Gamma Densitometer (Gamma) are two promising approaches for multiphase visualization and characterization in process industries. In two phase oil and gas flow, ECT and Gamma are used in multiphase flow monitoring techniques due to their inherent simplicity, robustness, and an ability to withstand wide range of operational temperatures and pressures. High viscous oil (viscosity > 100 cP) is of interest because of its huge reserves, technological advances in its production and unlike conventional oil (oil viscosity < 100 cP) and gas flows where ECT and Gamma have been previously used, high viscous oil and gas flows comes with certain associated concerns which include; increased entrainment of gas bubbles dispersed in oil, shorter and more frequent slugs as well as oil film coatings on the walls of flowing conduits. This study aims to determine the suitability of both devices in the visualization and characterization of high-viscous oil and gas flow. Static tests are performed with both devices and liquid holdup measurements are obtained. Dynamic experiments were also conducted in a 1 and 3 inch facility at Cranfield University with a range of nominal viscosities (1000, 3000 and 7500 cP). Plug, slug and wavy annular flow patterns were identified by means of Probability Mass Function and time series analysis of the data acquired from Gamma and ECT devices with high speed camera used to validate the results. Measured Liquid holdups for both devices were also compared.

  4. Gas-to-liquid technologies: India's perspective

    International Nuclear Information System (INIS)

    Reddy Keshav, Tirupati; Basu, S.

    2007-01-01

    Gas-to-liquid (GTL) technologies are capable of converting gas to clean, useful liquid hydrocarbons and thus suitable for addressing problems of remote gas utilization, increase in crude oil price, depletion of fossil fuel and environmental pollution. The Indian state of Tripura is considered to be the richest province with 26 billion cubic meters of gas reserves. Neighboring country Myanmar has huge gas reserves but these reserves remain unutilized mainly because of land-locked situation. GTL is a well developed and proven technology and it is an important option for moving natural gas to the market place. GTL options include not only the well-known production of Fischer-Tropsch synthesis liquids but also the production of oxygen containing fuels, fuel additives and chemicals, such as methanol and DME. An alternative, promising option to convert surplus gas is the direct route of methane conversion, which is more energy efficient than the indirect route since it bypasses the energy intensive endothermic steam reforming step of syngas formation. On-site conversion to liquid products of commercial importance using direct route would make transportation of these natural deposits much more economical and practical. In this paper an attempt has been made to review recent developments in syngas technologies, direct routes of methane conversion into useful liquids, and status of both existing and future developments in GTL industry around the world. Finally challenges in GTL technology are discussed. (author)

  5. A relative permeability model to derive fractional-flow functions of water-alternating-gas and surfactant-alternating-gas foam core-floods

    International Nuclear Information System (INIS)

    Al-Mossawy, Mohammed Idrees; Demiral, Birol; Raja, D M Anwar

    2013-01-01

    Foam is used in enhanced oil recovery to improve the sweep efficiency by controlling the gas mobility. The surfactant-alternating-gas (SAG) foam process is used as an alternative to the water-alternating-gas (WAG) injection. In the WAG technique, the high mobility and the low density of the gas lead the gas to flow in channels through the high permeability zones of the reservoir and to rise to the top of the reservoir by gravity segregation. As a result, the sweep efficiency decreases and there will be more residual oil in the reservoir. The foam can trap the gas in liquid films and reduces the gas mobility. The fractional-flow method describes the physics of immiscible displacements in porous media. Finding the water fractional flow theoretically or experimentally as a function of the water saturation represents the heart of this method. The relative permeability function is the conventional way to derive the fractional-flow function. This study presents an improved relative permeability model to derive the fractional-flow functions for WAG and SAG foam core-floods. The SAG flow regimes are characterized into weak foam, strong foam without a shock front and strong foam with a shock front. (paper)

  6. The Development and Test of a Sensor for Measurement of the Working Level of Gas-Liquid Two-Phase Flow in a Coalbed Methane Wellbore Annulus.

    Science.gov (United States)

    Wu, Chuan; Ding, Huafeng; Han, Lei

    2018-02-14

    Coalbed methane (CBM) is one kind of clean-burning gas and has been valued as a new form of energy that will be used widely in the near future. When producing CBM, the working level within a CBM wellbore annulus needs to be monitored to dynamically adjust the gas drainage and extraction processes. However, the existing method of measuring the working level does not meet the needs of accurate adjustment, so we designed a new sensor for this purpose. The principle of our sensor is a liquid pressure formula, i.e., the sensor monitors the two-phase flow patterns and obtains the mean density of the two-phase flow according to the pattern recognition result in the first step, and then combines the pressure data of the working level to calculate the working level using the liquid pressure formula. The sensor was tested in both the lab and on site, and the tests showed that the sensor's error was ±8% and that the sensor could function well in practical conditions and remain stable in the long term.

  7. Gas-liquid Two Phase Flow Modelling of Incompressible Fluid and Experimental Validation Studies in Vertical Centrifugal Casting

    International Nuclear Information System (INIS)

    Zhou, J X; Shen, X; Yin, Y J; Guo, Z; Wang, H

    2015-01-01

    In this paper, Gas-liquid two phase flow mathematic models of incompressible fluid were proposed to explore the feature of fluid under certain centrifugal force in vertical centrifugal casting (VCC). Modified projection-level-set method was introduced to solve the mathematic models. To validate the simulation results, two methods were used in this study. In the first method, the simulation result of basic VCC flow process was compared with its analytic solution. The relationship between the numerical solution and deterministic analytic solution was presented to verify the correctness of numerical algorithms. In the second method, systematic water simulation experiments were developed. In this initial experiment, special experimental vertical centrifugal device and casting shapes were designed to describe typical mold-filling processes in VCC. High speed camera system and data collection devices were used to capture flow shape during the mold-filling process. Moreover, fluid characteristic at different rotation speed (from 40rpm, 60rpmand 80rpm) was discussed to provide comparative resource for simulation results. As compared with the simulation results, the proposed mathematical models could be proven and the experimental design could help us advance the accuracy of simulation and further studies for VCC. (paper)

  8. Porous Metal Filters for Gas and Liquid Applications in the Nuclear Industry

    International Nuclear Information System (INIS)

    Kenneth, Rubow

    2009-01-01

    systems at various nuclear sites in the US, and 3) smaller flow rate in-line gas filters utilized in compressed gas lines, utility lines, vent lines and gas sampling lines typically found in laboratory and small pilot test systems using radioactive materials. These filter examples employ a wide range of filtration technology, e.g., large scale cross-flow filtration system for the concentrating of liquid waste, in-situ back-pulse cleanable gas filtration system primarily utilizing surface particle filtration, and smaller in-line gas filter utilizing particle removal via depth filtration. (authors)

  9. Numerical simulation study of gas-liquid reactive mass transfer along corrugated sheets with interface tracking

    International Nuclear Information System (INIS)

    Haroun, Y.

    2008-11-01

    This work is done within the framework of gas treatment and CO 2 capture process development. The main objective of the present work is to fill the gap between classical experiments and industrial conditions by the use of Computational Fluid Dynamics (CFD). The physical problem considered corresponds to the liquid film flow down a corrugate surface under gravity in present of a gas phase. The chemical species in the gas phase absorb in the liquid phase and react. Numerical calculations are carried out in order to determine the impact of physical and geometrical properties on reactive mass transfer in industrial operating conditions. (author)

  10. Hydrodynamics in a cocurrent gas-liquid trickle bed at elevated pressures

    NARCIS (Netherlands)

    Wammes, W.J.A.; Middelkamp, J.; Huisman, W.J.; Huisman, W.J.; de Baas, C.M.; de Baas, C.M.; Westerterp, K.R.

    1991-01-01

    Data on design and operation of trickle beds at elevated pressures are scarce. In this study the influence of the gas density on the liquid holdup, the pressure drop, and the transition between trickle and pulse flow has been investigated in a tricklebed reactor operating up to 7.5 MPa and with

  11. Prediction of evaporation heat transfer coefficient based on gas-liquid two-phase annular flow regime in horizontal microfin tubes

    International Nuclear Information System (INIS)

    Wang Yueshe; Wang Yanling; Wang, G.-X.; Honda, Hiroshi

    2009-01-01

    A physical model of gas-liquid two-phase annular flow regime is presented for predicting the enhanced evaporation heat transfer characteristics in horizontal microfin tubes. The model is based on the equivalence of a periodical distortion of the disturbance wave in the substrate layer. Corresponding to the stratified flow model proposed previously by authors, the dimensionless quantity Fr 0 = G/[gd e ρ v (ρ l - ρ v )] 0.5 may be used as a measure for determining the applicability of the present theoretical model, which was used to restrict the transition boundary between the stratified-wavy flow and the annular/intermittent flows. Comparison of the prediction of the circumferential average heat transfer coefficient with available experimental data for four tubes and three refrigerants reveals that a good agreement is obtained or the trend is better than that of the previously developed stratified flow model for Fr 0 > 4.0 as long as the partial dry out of tube does not occur. Obviously, the developed annular model is applicable and reliable for evaporation in horizontal microfin tubes under the case of high heat flux and high mass flux.

  12. Prediction of evaporation heat transfer coefficient based on gas-liquid two-phase annular flow regime in horizontal microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yueshe, E-mail: wangys@mail.xjtu.edu.cn [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Yanling, Wang [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Wang, G -X [Mechanical Engineering Department, The University of Akron, Akron, OH 44325-3903 (United States); Honda, Hiroshi [Kyushu University, 337 Kasuya-machi, Kasuya-gun, Kukuoka 811-2307 (Japan)

    2009-10-15

    A physical model of gas-liquid two-phase annular flow regime is presented for predicting the enhanced evaporation heat transfer characteristics in horizontal microfin tubes. The model is based on the equivalence of a periodical distortion of the disturbance wave in the substrate layer. Corresponding to the stratified flow model proposed previously by authors, the dimensionless quantity Fr{sub 0} = G/[gd{sub e}{rho}{sub v}({rho}{sub l} - {rho}{sub v})]{sup 0.5} may be used as a measure for determining the applicability of the present theoretical model, which was used to restrict the transition boundary between the stratified-wavy flow and the annular/intermittent flows. Comparison of the prediction of the circumferential average heat transfer coefficient with available experimental data for four tubes and three refrigerants reveals that a good agreement is obtained or the trend is better than that of the previously developed stratified flow model for Fr{sub 0} > 4.0 as long as the partial dry out of tube does not occur. Obviously, the developed annular model is applicable and reliable for evaporation in horizontal microfin tubes under the case of high heat flux and high mass flux.

  13. Flow structure of conical distributed multiple gas jets injected into a water chamber

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jiajun; Yu, Yonggang [Nanjing University of Science and Technology, Nanjing (China)

    2017-04-15

    Based on an underwater gun firing project, a mock bullet with several holes on the head was designed and experimented to observe the combustion gas injected into a cylindrical water chamber through this mock bullet. The combustion gas jets contain one vertical central jet and 4 to 8 slant lateral jets. A high speed camera system was used to record the expansion of gas jets in the experimental study. In numerical simulations, the Euler two-fluid model and volume of fluid method were adopted to describe the gas-liquid flow. The results show the backflow zone in lateral jet is the main factor influencing the gas-liquid turbulent mixing in downstream. On cross sections, the gas volume fraction increased with time but the growth rate decreased. With a change of nozzle structure, the gas fraction was more affected than the shock structure.

  14. US crude oil, natural gas, and natural gas liquids reserves 1996 annual report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    The EIA annual reserves report series is the only source of comprehensive domestic proved reserves estimates. This publication is used by the Congress, Federal and State agencies, industry, and other interested parties to obtain accurate estimates of the Nation`s proved reserves of crude oil, natural gas, and natural gas liquids. These data are essential to the development, implementation, and evaluation of energy policy and legislation. This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1996, as well as production volumes for the US and selected States and State subdivisions for the year 1996. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), nonassociated gas and associated-dissolved gas (which are the two major types of wet natural gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, reserve estimates for two types of natural gas liquids, lease condensate and natural gas plant liquids, are presented. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. A discussion of notable oil and gas exploration and development activities during 1996 is provided. 21 figs., 16 tabs.

  15. Liquid Hydrogen Recirculation System for Forced Flow Cooling Test of Superconducting Conductors

    Science.gov (United States)

    Shirai, Y.; Kainuma, T.; Shigeta, H.; Shiotsu, M.; Tatsumoto, H.; Naruo, Y.; Kobayashi, H.; Nonaka, S.; Inatani, Y.; Yoshinaga, S.

    2017-12-01

    The knowledge of forced flow heat transfer characteristics of liquid hydrogen (LH2) is important and necessary for design and cooling analysis of high critical temperature superconducting devices. However, there are few test facilities available for LH2 forced flow cooling for superconductors. A test system to provide a LH2 forced flow (∼10 m/s) of a short period (less than 100 s) has been developed. The test system was composed of two LH2 tanks connected by a transfer line with a controllable valve, in which the forced flow rate and its period were limited by the storage capacity of tanks. In this paper, a liquid hydrogen recirculation system, which was designed and fabricated in order to study characteristics of superconducting cables in a stable forced flow of liquid hydrogen for longer period, was described. This LH2 loop system consists of a centrifugal pump with dynamic gas bearings, a heat exchanger which is immersed in a liquid hydrogen tank, and a buffer tank where a test section (superconducting wires or cables) is set. The buffer tank has LHe cooled superconducting magnet which can produce an external magnetic field (up to 7T) at the test section. A performance test was conducted. The maximum flow rate was 43.7 g/s. The lowest temperature was 22.5 K. It was confirmed that the liquid hydrogen can stably circulate for 7 hours.

  16. Fundamental study on the response analysis of liquid tracer in gas-liquid, two-phase steady flow in porous media; Takoshitsu sonai kieki niso teijoryu ni okeru ekiso tracer no oto kaiseki ni kansuru kisoteki kento

    Energy Technology Data Exchange (ETDEWEB)

    Haga, D; Niibori, Y; Chida, T [Tohoku University, Sendai (Japan)

    1998-10-25

    Fluids in geothermal reservoirs are not necessarily in the single phase but is occasionally in the gas-liquid double phase. This study aims to collect fundamental knowledge about the analysis of tracer responses in a gas-liquid two-phase flow, with special attention paid to the movement of substances in the liquid-phase portion of the two-phase flow. A tracer test is conducted in a glass bead-filled layer, and then it is found that the conventional mixture-diffusion model fails to explain the outcome of the test conducted using the said very simple apparatus. The failure is attributed to the coexistence of high-saturation and low-saturation layers throughout the glass bead-filled layer, and a mathematical model is formulated, which is a development from the two-fractured-layer (TFL) model. It turns out that the mathematical model excellently describes the test result that the mixture-diffusion model fails to explain. In the numerical solution of this problem, the validity is confirmed of the use of the SIMPLEX method for the estimation of the effect of the numerical dispersion term of the third-order accurate finite upstream difference method, and of unknown parameters. 31 refs., 7 figs., 1 tab.

  17. Fluid flow in gas condensate reservoirs. The interplay of forces and their relative strengths

    Energy Technology Data Exchange (ETDEWEB)

    Ursin, Jann-Rune [Stavanger University College, Department of Petroleum Engineering, PO Box 8002, Stavanger, 4068 (Norway)

    2004-02-01

    Natural production from gas condensate reservoirs is characterized by gas condensation and liquid dropout in the reservoir, first in the near wellbore volume, then as a cylindrical shaped region, dynamically developing into the reservoir volume. The effects of liquid condensation are reduced productivity and loss of production. Successful forecast of well productivity and reservoir production depends on detailed understanding of the effect of various forces acting on fluid flow in time and space. The production form gas condensate reservoirs is thus indirectly related to the interplay of fundamental forces, such as the viscosity, the capillary, the gravitational and the inertial force and their relative strengths, demonstrated by various dimensionless numbers. Dimensionless numbers are defined and calculated for all pressure and space coordinates in a test reservoir. Various regions are identified where certain forces are more important than others. Based on reservoir pressure development, liquid condensation and the numerical representation of dimensionless numbers, a conceptual understanding of a varying reservoir permeability has been reached.The material balance, the reservoir fluid flow and the wellbore flow calculations are performed on a cylindrical reservoir model. The ratios between fundamental forces are calculated and dimensionless numbers defined. The interplay of forces, demonstrated by these numbers, are calculated as function of radial dimension and reservoir pressure.

  18. U.S. crude oil, natural gas, and natural gas liquids reserves 1997 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Wood, John H.; Grape, Steven G.; Green, Rhonda S.

    1998-12-01

    This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1997, as well as production volumes for the US and selected States and State subdivisions for the year 1997. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), nonassociated gas and associated-dissolved gas (which are the two major types of wet natural gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, reserve estimates for two types of natural gas liquids, lease condensate and natural gas plant liquids, are presented. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. A discussion of notable oil and gas exploration and development activities during 1997 is provided. 21 figs., 16 tabs.

  19. Bubble-induced mixing of two horizontal liquid layers with non-uniform gas injection at the bottom

    International Nuclear Information System (INIS)

    Cheung, F.B.; Leinweber, G.; Pedersen, D.R.

    1984-01-01

    During a postulated severe core meltdown accident in an LMFBR, a large amount of sodium coolant may spill into the reactor concrete cavity. A layer of liquid products may form as a result of the sodium-concrete reactions. The liquid product layer, which is highly viscous and much heavier than sodium, separates the concrete from the sodium pool. In general, the downward transport of sodium through the liquid product layer to the unreacted concrete surface, which controls the rate of chemical erosion of the concrete, depends strongly on the agitation induced by gas evolution from the heated concrete. In this study, experiments were conducted to explore the effect of non-uniform gas injection on mixing of two horizontal mutually soluble liquid layers. The liquid in the lower layer was chosen to be more viscous and heavier than the liquid in the upper layer. To simulate the reactor accident situation, gas was injected at the bottom of the liquid-liquid system through a circular hole that covered only the center portion of the bottom surface of the lower liquid layer. The bubble-induced mixing motions were observed and the rate of mixing was measured for different hole sizes and for various gas flow rates

  20. Modeling of information flows in natural gas storage facility

    Science.gov (United States)

    Ranjbari, Leyla; Bahar, Arifah; Aziz, Zainal Abdul

    2013-09-01

    The paper considers the natural-gas storage valuation based on the information-based pricing framework of Brody-Hughston-Macrina (BHM). As opposed to many studies which the associated filtration is considered pre-specified, this work tries to construct the filtration in terms of the information provided to the market. The value of the storage is given by the sum of the discounted expectations of the cash flows under risk-neutral measure, conditional to the constructed filtration with the Brownian bridge noise term. In order to model the flow of information about the cash flows, we assume the existence of a fixed pricing kernel with liquid, homogenous and incomplete market without arbitrage.

  1. The effect of dry spots on heat transfer in a locally heated liquid film moving under the action of gas flow in a channel

    Science.gov (United States)

    Zaitsev, D. V.; Tkachenko, E. M.; Bykovskaya, E. F.

    2017-11-01

    Intensive evaporation of a thin liquid film, moving in a flat micro-/minichannel under the action of gas flow is very promising for the use in cooling systems of modern semiconductor devices with localized heat sources of high intensity. In this work, using the high-speed visualization, the effect of the formation of dry spots on heat transfer in a locally heated liquid film shear-driven in a channel was investigated. It was found that the maximum intensity of heat removal from the heater is achieved in the mode, when the film flow continuity is broken. During the experiment the total area of dry spots increases with increasing heat flux and heater temperature, but when the heater reaches a certain temperature (≈100°C), the total area begins to decrease. However, the length of contact line increases with increasing heat flux and reaches a maximum in the pre-crisis regime. Intensive evaporation in the region of the contact line may explain the achievement of high heat fluxes in the shear-driven liquid film.

  2. Process optimization for microcystin-LR degradation by Response Surface Methodology and mechanism analysis in gas-liquid hybrid discharge system.

    Science.gov (United States)

    Zhang, Yi; Wei, Hanyu; Xin, Qing; Wang, Mingang; Wang, Qi; Wang, Qiang; Cong, Yanqing

    2016-12-01

    A gas-liquid hybrid discharge system was applied to microcystin-LR (MC-LR) degradation. MC-LR degradation was completed after 1 min under a pulsed high voltage of 16 kV, gas-liquid interface gap of 10 mm and oxygen flow rate of 160 L/h. The Box-Behnken Design was proposed in Response Surface Methodology to evaluate the influence of pulsed high voltage, electrode distance and oxygen flow rate on MC-LR removal efficiency. Multiple regression analysis, focused on multivariable factors, was employed and a reduced cubic model was developed. The ANOVA analysis shows that the model is significant and the model prediction on MC-LR removal was also validated with experimental data. The optimum conditions for the process are obtained at pulsed voltage of 16 kV, gas-liquid interface gap of 10 mm and oxygen flow rate of 120 L/h with ta removal efficiency of MC-LR of 96.6%. The addition of catalysts (TiO 2 or Fe 2+ ) in the gas-liquid hybrid discharge system was found to enhance the removal of MC-LR. The intermediates of MC-LR degradation were analyzed by liquid chromatography/mass spectrometry. The degradation pathway proposed envisaged the oxidation of hydroxyl radicals and ozone, and attack of high-energy electrons on the unsaturated double bonds of Adda and Mdha, with MC-LR finally decomposing into small molecular products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Ionic liquid stationary phases for gas chromatography.

    Science.gov (United States)

    Poole, Colin F; Poole, Salwa K

    2011-04-01

    This article provides a summary of the development of ionic liquids as stationary phases for gas chromatography beginning with early work on packed columns that established details of the retention mechanism and established working methods to characterize selectivity differences compared with molecular stationary phases through the modern development of multi-centered cation and cross-linked ionic liquids for high-temperature applications in capillary gas chromatography. Since there are many reviews on ionic liquids dealing with all aspects of their chemical and physical properties, the emphasis in this article is placed on the role of gas chromatography played in the design of ionic liquids of low melting point, high thermal stability, high viscosity, and variable selectivity for separations. Ionic liquids provide unprecedented opportunities for extending the selectivity range and temperature-operating range of columns for gas chromatography, an area of separation science that has otherwise been almost stagnant for over a decade. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Characterisation of the interaction between liquid film and flue gas flow at walls and internals in FGD scrubbers; Beschreibung der gegenseitigen Beeinflussung von Fluessigkeitsschicht und Rauchgasstroemung an Waenden und internen Einbauten in REA-Waeschern

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, Mario [Technische Univ. Dortmund (Germany). Lehrstuhl Mechanische Verfahrenstechnik; Fahlenkamp, Hans

    2012-07-01

    The VGB Research Project 'Characterisation of the interaction between liquid film and flue gas flow at walls and internals in FGD scrubbers' covers the droplet wall interaction in flue gas scrubbers. In the context of optimised FGD design, especially in fulfilling the increasing requirements on the conventional flue gas treatment by the CCS design, a better understanding of the flow behaviour near the wall is crucial. Within the framework of the research project an experimental setup is designed, built up and run. (orig.)

  5. Liquid-liquid extraction in flow analysis: A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Silvestre, Cristina I.C.; Santos, Joao L.M. [REQUIMTE, Servico de Quimica-Fisica, Faculdade de Farmacia, Universidade do Porto, R. Anibal Cunha, 164, 4099-030 Porto (Portugal); Lima, Jose L.F.C., E-mail: limajlfc@ff.up.pt [REQUIMTE, Servico de Quimica-Fisica, Faculdade de Farmacia, Universidade do Porto, R. Anibal Cunha, 164, 4099-030 Porto (Portugal); Zagatto, Elias A.G. [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, P.O. Box 96, Piracicaba 13400-970 (Brazil)

    2009-10-12

    Liquid-liquid extractions (LLE) are a common sample pre-treatment in many analytical applications. This review aims at providing a critical overview of the distinct automated continuous flow-based approaches that were developed for liquid-liquid extraction with the purpose of pre-concentration and/or separation of multiple analytes, such as ultra-trace metal and metalloid species, phenolic compounds, surfactants, pharmaceuticals, etc., hyphenated with many detection technique such as UV/vis spectrophotometry, atomic spectrometric detection systems and luminescent detectors, including distinct extraction strategies and applications like single and multiple extraction schemes, wetting film extraction, supported liquid membrane extraction, back extraction, closed-loop systems and the utilisation of zone sampling, chromatomembranes and iterative reversal techniques. The analytical performance of the developed flow-based LLE methods and the influence of flow manifold components such as the segmenter, extraction coil and phase separator, is emphasised and object of discussion. An overall presentation of each system components, selectivity, advantages and shortcomings is carried out and exemplified with selected applications.

  6. A Novel Acoustic Liquid Level Determination Method for Coal Seam Gas Wells Based on Autocorrelation Analysis

    Directory of Open Access Journals (Sweden)

    Ximing Zhang

    2017-11-01

    Full Text Available In coal seam gas (CSG wells, water is periodically removed from the wellbore in order to keep the bottom-hole flowing pressure at low levels, facilitating the desorption of methane gas from the coal bed. In order to calculate gas flow rate and further optimize well performance, it is necessary to accurately monitor the liquid level in real-time. This paper presents a novel method based on autocorrelation function (ACF analysis for determining the liquid level in CSG wells under intense noise conditions. The method involves the calculation of the acoustic travel time in the annulus and processing the autocorrelation signal in order to extract the weak echo under high background noise. In contrast to previous works, the non-linear dependence of the acoustic velocity on temperature and pressure is taken into account. To locate the liquid level of a coal seam gas well the travel time is computed iteratively with the non-linear velocity model. Afterwards, the proposed method is validated using experimental laboratory investigations that have been developed for liquid level detection under two scenarios, representing the combination of low pressure, weak signal, and intense noise generated by gas flowing and leakage. By adopting an evaluation indicator called Crest Factor, the results have shown the superiority of the ACF-based method compared to Fourier filtering (FFT. In the two scenarios, the maximal measurement error from the proposed method was 0.34% and 0.50%, respectively. The latent periodic characteristic of the reflected signal can be extracted by the ACF-based method even when the noise is larger than 1.42 Pa, which is impossible for FFT-based de-noising. A case study focused on a specific CSG well is presented to illustrate the feasibility of the proposed approach, and also to demonstrate that signal processing with autocorrelation analysis can improve the sensitivity of the detection system.

  7. Thermal transistor utilizing gas-liquid transition

    KAUST Repository

    Komatsu, Teruhisa S.

    2011-01-25

    We propose a simple thermal transistor, a device to control heat current. In order to effectively change the current, we utilize the gas-liquid transition of the heat-conducting medium (fluid) because the gas region can act as a good thermal insulator. The three terminals of the transistor are located at both ends and the center of the system, and are put into contact with distinct heat baths. The key idea is a special arrangement of the three terminals. The temperature at one end (the gate temperature) is used as an input signal to control the heat current between the center (source, hot) and another end (drain, cold). Simulating the nanoscale systems of this transistor, control of heat current is demonstrated. The heat current is effectively cut off when the gate temperature is cold and it flows normally when it is hot. By using an extended version of this transistor, we also simulate a primitive application for an inverter. © 2011 American Physical Society.

  8. Comparison of electrical and optical characteristics in gas-phase and gas-liquid phase discharges

    Energy Technology Data Exchange (ETDEWEB)

    Qazi, H. I. A.; Li, He-Ping, E-mail: liheping@tsinghua.edu.cn; Zhang, Xiao-Fei; Bao, Cheng-Yu [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Nie, Qiu-Yue [School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin, Heilongjiang Province 150001 (China)

    2015-12-15

    This paper presents an AC-excited argon discharge generated using a gas-liquid (two-phase) hybrid plasma reactor, which mainly consists of a powered needle electrode enclosed in a conical quartz tube and grounded deionized water electrode. The discharges in the gas-phase, as well as in the two-phase, exhibit two discharge modes, i.e., the low current glow-like diffuse mode and the high current streamer-like constrict mode, with a mode transition, which exhibits a negative resistance of the discharges. The optical emission spectral analysis shows that the stronger diffusion of the water vapor into the discharge region in the two-phase discharges boosts up the generation of OH (A–X) radicals, and consequently, leads to a higher rotational temperature in the water-phase plasma plume than that of the gas-phase discharges. Both the increase of the power input and the decrease of the argon flow rate result in the increase of the rotational temperature in the plasma plume of the water-phase discharge. The stable two-phase discharges with a long plasma plume in the water-phase under a low power input and gas flow rate may show a promising prospect for the degradation of organic pollutants, e.g., printing and dyeing wastewater, in the field of environmental protection.

  9. Cavitation in gas-saturated liquids

    NARCIS (Netherlands)

    Rooze, J.

    2012-01-01

    Oscillating gas bubbles can be created in a liquid by exposing it to ultrasound. These gas bubbles implode if the sound pressure is high enough. This process is called cavitation. Interesting phenomena take place during the collapse. The gas and vapour inside the bubble are compressed and reach

  10. U.S. crude oil, natural gas, and natural gas liquids reserves 1995 annual report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-11-01

    The EIA annual reserves report series is the only source of comprehensive domestic proved reserves estimates. This publication is used by the Congress, Federal and State agencies, industry, and other interested parties to obtain accurate estimates of the Nation`s proved reserves of crude oil, natural gas, and natural gas liquids. These data are essential to the development, implementation, and evaluation of energy policy and legislation. This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1995, as well as production volumes for the US and selected States and State subdivisions for the year 1995. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), nonassociated gas and associated-dissolved gas (which are the two major types of wet natural gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, reserve estimates for two types of natural gas liquids, lease condensate and natural gas plant liquids, are presented. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. A discussion of notable oil and gas exploration and development activities during 1995 is provided. 21 figs., 16 tabs.

  11. The influence of liquid-gas velocity ratio on the noise of the cooling tower

    Science.gov (United States)

    Yang, Bin; Liu, Xuanzuo; Chen, Chi; Zhao, Zhouli; Song, Jinchun

    2018-05-01

    The noise from the cooling tower has a great influence on psychological performance of human beings. The cooling tower noise mainly consists of fan noise, falling water noise and mechanical noise. This thesis used DES turbulence model with FH-W model to simulate the flow and sound pressure field in cooling tower based on CFD software FLUENT and analyzed the influence of different kinds noise, which affected by diverse factors, on the cooling tower noise. It can be concluded that the addition of cooling water can reduce the turbulence and vortex noise of the rotor fluid field in the cooling tower at some extent, but increase the impact noise of the liquid-gas two phase. In general, the cooling tower noise decreases with the velocity ratio of liquid to gas increasing, and reaches the lowest when the velocity ratio of liquid to gas is close to l.

  12. Retention/Diffusivity Studies in Free-Surface Flowing Liquid Lithium

    International Nuclear Information System (INIS)

    R.A. Stubbers; G.H. Miley; M. Nieto; W. Olczak; D.N. Ruzic; A. Hassanein

    2004-01-01

    FLIRE was designed to measure the hydrogen and helium retention and diffusivity in a flowing stream of liquid lithium, and it has accomplished these goals. Retention coefficients for helium in the flowing liquid stream were 0.1-2% for flow speeds of 44 cm/s and implantation energies between 500 and 2000 eV. The energy dependence of retention is linear for the energy range considered, as expected, and the dependence of retention on flow velocity fits the expected square-root of flow speed dependence. Estimates of the helium diffusion coefficient in the flowing lithium stream were ∼ 4 x 10 -7 cm 2 /s, and are independent of implantation energy. This value is much lower than expected, which could be due to several factors, such as mixing, bubble formation or surface film formation. In the case of hydrogen, long term retention and release mechanisms are of greatest importance, since this relates to tritium inventory in flowing lithium PFCs for fusion applications. The amount of hydride formation was measured for flowing lithium exposed to neutral deuterium gas. Thermal desorption spectroscopy (TDS) measurements indicate that the hydride concentration was between 0.1 and 0.2% over a wide range of pressures (6.5 x 10 -5 to 1 Torr). This result implies that the deuterium absorption rate is limited by the surface dissociation rate, since deuterium (hydrogen/tritium) is absorbed in its atomic form, not its molecular form

  13. Retention/Diffusivity Studies in Free-Surface Flowing Liquid Lithium

    Energy Technology Data Exchange (ETDEWEB)

    R.A. Stubbers; G.H. Miley; M. Nieto; W. Olczak; D.N. Ruzic; A. Hassanein

    2004-12-14

    FLIRE was designed to measure the hydrogen and helium retention and diffusivity in a flowing stream of liquid lithium, and it has accomplished these goals. Retention coefficients for helium in the flowing liquid stream were 0.1-2% for flow speeds of 44 cm/s and implantation energies between 500 and 2000 eV. The energy dependence of retention is linear for the energy range considered, as expected, and the dependence of retention on flow velocity fits the expected square-root of flow speed dependence. Estimates of the helium diffusion coefficient in the flowing lithium stream were {approx} 4 x 10{sup -7} cm{sup 2}/s, and are independent of implantation energy. This value is much lower than expected, which could be due to several factors, such as mixing, bubble formation or surface film formation. In the case of hydrogen, long term retention and release mechanisms are of greatest importance, since this relates to tritium inventory in flowing lithium PFCs for fusion applications. The amount of hydride formation was measured for flowing lithium exposed to neutral deuterium gas. Thermal desorption spectroscopy (TDS) measurements indicate that the hydride concentration was between 0.1 and 0.2% over a wide range of pressures (6.5 x 10{sup -5} to 1 Torr). This result implies that the deuterium absorption rate is limited by the surface dissociation rate, since deuterium (hydrogen/tritium) is absorbed in its atomic form, not its molecular form.

  14. Influence of liquid viscosity and surface tension on the gas-liquid mass transfer coefficient for solid foam packings in co-current two-phase flow

    NARCIS (Netherlands)

    Stemmet, C.P.; Bartelds, F.; Schaaf, van der J.; Kuster, B.F.M.; Schouten, J.C.

    2008-01-01

    The gas–liquid mass transfer coefficient and other hydrodynamic parameters such as liquid holdup and frictional pressure drop are presented for gas and liquid moving in co-current upflow and downflow through solid foam packings of 10 and of 40 pores per linear inch (ppi). The effect of increasing

  15. Intelligent gas-mixture flow sensor

    NARCIS (Netherlands)

    Lammerink, Theodorus S.J.; Dijkstra, Fred; Houkes, Z.; van Kuijk, J.C.C.; van Kuijk, Joost

    A simple way to realize a gas-mixture flow sensor is presented. The sensor is capable of measuring two parameters from a gas flow. Both the flow rate and the helium content of a helium-nitrogen gas mixture are measured. The sensor exploits two measurement principles in combination with (local)

  16. Balance of liquid-phase turbulence kinetic energy equation for bubble-train flow

    International Nuclear Information System (INIS)

    Ilic, Milica; Woerner, Martin; Cacuci, Dan Gabriel

    2004-01-01

    In this paper the investigation of bubble-induced turbulence using direct numerical simulation (DNS) of bubbly two-phase flow is reported. DNS computations are performed for a bubble-driven liquid motion induced by a regular train of ellipsoidal bubbles rising through an initially stagnant liquid within a plane vertical channel. DNS data are used to evaluate balance terms in the balance equation for the liquid phase turbulence kinetic energy. The evaluation comprises single-phase-like terms (diffusion, dissipation and production) as well as the interfacial term. Special emphasis is placed on the procedure for evaluation of interfacial quantities. Quantitative analysis of the balance equation for the liquid phase turbulence kinetic energy shows the importance of the interfacial term which is the only source term. The DNS results are further used to validate closure assumptions employed in modelling of the liquid phase turbulence kinetic energy transport in gas-liquid bubbly flows. In this context, the performance of respective closure relations in the transport equation for liquid turbulence kinetic energy within the two-phase k-ε and the two-phase k-l model is evaluated. (author)

  17. Hybrid Multiphase CFD Solver for Coupled Dispersed/Segregated Flows in Liquid-Liquid Extraction

    Directory of Open Access Journals (Sweden)

    Kent E. Wardle

    2013-01-01

    Full Text Available The flows in stage-wise liquid-liquid extraction devices include both phase segregated and dispersed flow regimes. As a additional layer of complexity, for extraction equipment such as the annular centrifugal contactor, free-surface flows also play a critical role in both the mixing and separation regions of the device and cannot be neglected. Traditionally, computional fluid dynamics (CFD of multiphase systems is regime dependent—different methods are used for segregated and dispersed flows. A hybrid multiphase method based on the combination of an Eulerian multifluid solution framework (per-phase momentum equations and sharp interface capturing using Volume of Fluid (VOF on selected phase pairs has been developed using the open-source CFD toolkit OpenFOAM. Demonstration of the solver capability is presented through various examples relevant to liquid-liquid extraction device flows including three-phase, liquid-liquid-air simulations in which a sharp interface is maintained between each liquid and air, but dispersed phase modeling is used for the liquid-liquid interactions.

  18. Fundamentals of gas particle flow

    CERN Document Server

    Rudinger, G

    1980-01-01

    Fundamentals of Gas-Particle Flow is an edited, updated, and expanded version of a number of lectures presented on the "Gas-Solid Suspensions” course organized by the von Karman Institute for Fluid Dynamics. Materials presented in this book are mostly analytical in nature, but some experimental techniques are included. The book focuses on relaxation processes, including the viscous drag of single particles, drag in gas-particles flow, gas-particle heat transfer, equilibrium, and frozen flow. It also discusses the dynamics of single particles, such as particles in an arbitrary flow, in a r

  19. PREDICTION OF GAS HOLD-UP IN A COMBINED LOOP AIR LIFT FLUIDIZED BED REACTOR USING NEWTONIAN AND NON-NEWTONIAN LIQUIDS

    Directory of Open Access Journals (Sweden)

    Sivakumar Venkatachalam

    2011-09-01

    Full Text Available Many experiments have been conducted to study the hydrodynamic characteristics of column reactors and loop reactors. In this present work, a novel combined loop airlift fluidized bed reactor was developed to study the effect of superficial gas and liquid velocities, particle diameter, fluid properties on gas holdup by using Newtonian and non-Newtonian liquids. Compressed air was used as gas phase. Water, 5% n-butanol, various concentrations of glycerol (60 and 80% were used as Newtonian liquids, and different concentrations of carboxy methyl cellulose aqueous solutions (0.25, 0.6 and 1.0% were used as non-Newtonian liquids. Different sizes of spheres, Bearl saddles and Raschig rings were used as solid phases. From the experimental results, it was found that the increase in superficial gas velocity increases the gas holdup, but it decreases with increase in superficial liquid velocity and viscosity of liquids. Based on the experimental results a correlation was developed to predict the gas hold-up for Newtonian and non-Newtonian liquids for a wide range of operating conditions at a homogeneous flow regime where the superficial gas velocity is approximately less than 5 cm/s

  20. Pulsing flow in trickle bed columns

    NARCIS (Netherlands)

    Blok, Jan Rudolf

    1981-01-01

    In the operation of a packed column with cocurrent downflow of gas and liquid (trickle bed) several flowpatterns can be observed depending on the degree of interaction between gas and liquid. At low liquid and gas flow rates - low interaction - gascontinuous flow occurs. In this flowregime, the

  1. Multi-dimensional modeling of gas-liquid two-phase flows. Application to the simulation of ascending bubble flows in vertical ducts; Modelisation multidimensionnelle des ecoulements diphasiques gaz-liquide. Application a la simulation des ecoulements a bulles ascendants en conduite verticale

    Energy Technology Data Exchange (ETDEWEB)

    Morel, Ch

    1997-10-31

    The aim of this thesis is the 3-D modeling and numerical simulation of liquid/gas (water/vapor or water/air) two-phase flows in cooling circuits of nuclear power plants during normal and accidental situations. The development of a multidimensional dual-fluid model encounters two problems: the statistical effects of turbulence and the interface mass, momentum and energy transfers. The models developed in this study were introduced in the 3-D module of the CATHARE code developed by the CEA and the results were compared to experimental results available in the literature. The first chapter describes the equations of the local dual-fluid model for the 3-D description of two-phase flows. Closing relations adapted to dispersed flows with isothermal bubbles and without phase transformation are proposed and focus on the momentum transfer at the interfaces. The theoretical study of turbulence in the liquid phase of a bubble flow is modelled in chapter 2. Chapter 3 deals with the voluminal interface area used in the interface mass, momentum and energy transfers, and chapters 4 and 5 concern the application of the developed models to concrete situations. Chapter 4 describes in details the 3-D module of the CATHARE code while chapter 5 gives a comparison of numerical results obtained using the CATHARE code with other experimental results obtained at EdF. (J.S.) 109 refs.

  2. Maximize Liquid Oil Production from Shale Oil and Gas Condensate Reservoirs by Cyclic Gas Injection

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, James [Texas Tech Univ., Lubbock, TX (United States); Li, Lei [Texas Tech Univ., Lubbock, TX (United States); Yu, Yang [Texas Tech Univ., Lubbock, TX (United States); Meng, Xingbang [Texas Tech Univ., Lubbock, TX (United States); Sharma, Sharanya [Texas Tech Univ., Lubbock, TX (United States); Huang, Siyuan [Texas Tech Univ., Lubbock, TX (United States); Shen, Ziqi [Texas Tech Univ., Lubbock, TX (United States); Zhang, Yao [Texas Tech Univ., Lubbock, TX (United States); Wang, Xiukun [Texas Tech Univ., Lubbock, TX (United States); Carey, Bill [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nguyen, Phong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Porter, Mark [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jimenez-Martinez, Joaquin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Viswanathan, Hari [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mody, Fersheed [Apache Corp., Houston, TX (United States); Barnes, Warren [Apache Corp., Houston, TX (United States); Cook, Tim [Apache Corp., Houston, TX (United States); Griffith, Paul [Apache Corp., Houston, TX (United States)

    2017-11-17

    The current technology to produce shale oil reservoirs is the primary depletion using fractured wells (generally horizontal wells). The oil recovery is less than 10%. The prize to enhance oil recovery (EOR) is big. Based on our earlier simulation study, huff-n-puff gas injection has the highest EOR potential. This project was to explore the potential extensively and from broader aspects. The huff-n-puff gas injection was compared with gas flooding, water huff-n-puff and waterflooding. The potential to mitigate liquid blockage was also studied and the gas huff-n-puff method was compared with other solvent methods. Field pilot tests were initiated but terminated owing to the low oil price and the operator’s budget cut. To meet the original project objectives, efforts were made to review existing and relevant field projects in shale and tight reservoirs. The fundamental flow in nanopores was also studied.

  3. Theoretical background and the flow fields in downhole liquid-liquid hydrocyclone (LLHC

    Directory of Open Access Journals (Sweden)

    Osei Harrison

    2014-07-01

    Full Text Available Hydrocyclone system for downhole oil-water separation provides an effective technique of enhancing the economic viability of higher water-cut wells while at the same time reducing the risk of environmental pollution. This paper describes the hydrodynamics of the liquid-liquid hydrocyclones and the flow fields within it are paramount for achieving successful separation process. Some of the important hydrodynamic flow phenomenon within the liquid-liquid hydrocyclone and how they influence the separation efficiency of water/oil was analyzed through analytical solution. The properties of the liquids were based on Bayan offshore field measured properties. The results indicated that there are two swirling zones separated by stagnant flow field. The inner is the light liquid zone, while the outer is the heavy liquid zone.

  4. Direct measurements of liquid film roughness for the prediction of annular flow pressure drop

    International Nuclear Information System (INIS)

    Ashwood, Andrea C.; Schubring, DuWayne; Shedd, Timothy A.

    2009-01-01

    A vertical two-phase (air-water) test section has been constructed to allow for detailed visualization of flow phenomena in the annular regime. The total internal reflection (TIR) technique for film thickness estimation, originally developed by Shedd and Newell (1998), has been adapted for use in this test section. This technique uses the pattern of diffuse light reflected from the gas-liquid interface to estimate the base film thickness, i.e., the thickness between large liquid waves. Measurement of base film thickness separately from the average film thickness, which couples base film and wave behavior, allows for consideration of separate effects from each of the two zones. A modified Hurlburt-Newell (2000) correlation that separates the flow into these two zones has been generated. Data regarding the relationship between average base film thickness and wave height, along with verification of the base film thickness measured from the TIR technique, were provided by planar laser-induced fluorescence (PLIF). For the present vertical air-water up flows with liquid superficial velocities ranging from 4 to 34 cm s -1 and gas superficial velocities from 35 to 85 m s -1 , the modified Hurlburt-Newell correlation predicts pressure loss to within 10%. (author)

  5. Direct measurements of liquid film roughness for the prediction of annular flow pressure drop

    Energy Technology Data Exchange (ETDEWEB)

    Ashwood, Andrea C; Schubring, DuWayne; Shedd, Timothy A. [University of Wisconsin, Madison, WI (United States)], e-mail: cashwood@wisc.edu, e-mail: dlschubring@wisc.edu, e-mail: shedd@engr.wisc.edu

    2009-07-01

    A vertical two-phase (air-water) test section has been constructed to allow for detailed visualization of flow phenomena in the annular regime. The total internal reflection (TIR) technique for film thickness estimation, originally developed by Shedd and Newell (1998), has been adapted for use in this test section. This technique uses the pattern of diffuse light reflected from the gas-liquid interface to estimate the base film thickness, i.e., the thickness between large liquid waves. Measurement of base film thickness separately from the average film thickness, which couples base film and wave behavior, allows for consideration of separate effects from each of the two zones. A modified Hurlburt-Newell (2000) correlation that separates the flow into these two zones has been generated. Data regarding the relationship between average base film thickness and wave height, along with verification of the base film thickness measured from the TIR technique, were provided by planar laser-induced fluorescence (PLIF). For the present vertical air-water up flows with liquid superficial velocities ranging from 4 to 34 cm s{sup -1} and gas superficial velocities from 35 to 85 m s{sup -1}, the modified Hurlburt-Newell correlation predicts pressure loss to within 10%. (author)

  6. On intermittent flow characteristics of gas–liquid two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Thaker, Jignesh; Banerjee, Jyotirmay, E-mail: jbaner@gmail.com

    2016-12-15

    Highlights: • Unified correlations for intermittent flow characteristics are developed. • Influence of inflow conditions on intermittent flow characteristics is analysed. • Developed correlations can be used for effective design of piping components. - Abstract: Flow visualisation experiments are reported for intermittent regime of gas–liquid two-phase flow. Intermittent flow characteristics, which include plug/slug frequency, liquid plug/slug velocity, liquid plug/slug length, and plug/slug bubble length are determined by image processing of flow patterns captured at a rate of 1600 frames per second (FPS). Flow characteristics are established as a function of inlet superficial velocity of both the phases (in terms of Re{sub SL} and Re{sub SG}). The experimental results are first validated with the existing correlations for slug flow available in literature. It is observed that the correlations proposed in literature for slug flow do not accurately predict the flow characteristics in the plug flow regime. The differences are clearly highlighted in this paper. Based on the measured database for both plug and slug flow regime, modified correlations for the intermittent flow regime are proposed. The correlations reported in the present paper, which also include plug flow characteristics will aid immensely to the effective design and optimization of operating conditions for safer operation of two-phase flow piping systems.

  7. Inductive flow meter for measuring the speed of flow and gas volume contained in a flow of liquid metal

    International Nuclear Information System (INIS)

    Mueller, S.

    1980-01-01

    The speed of flow of the sodium is measured in two closely adjacent flow crossections using pairs of electrodes in the field of two disc-shaped permanent magnets made of AlNiCo 450, by means of measurements of running time of speed fluctuations. The result of the measurement is independent of the temperature of the sensor and the temperature of the sodium. The same arrangement makes it possible to determine the proportion by volume of the fission gas in sodium with a limiting freequency of several kHz. (DG) [de

  8. Shock wave of vapor-liquid two-phase flow

    Institute of Scientific and Technical Information of China (English)

    Liangju ZHAO; Fei WANG; Hong GAO; Jingwen TANG; Yuexiang YUAN

    2008-01-01

    The shock wave of vapor-liquid two-phase flow in a pressure-gain steam injector is studied by build-ing a mathematic model and making calculations. The results show that after the shock, the vapor is nearly com-pletely condensed. The upstream Mach number and the volume ratio of vapor have a great effect on the shock. The pressure and Mach number of two-phase shock con-form to the shock of ideal gas. The analysis of available energy shows that the shock is an irreversible process with entropy increase.

  9. Wet gas flow modeling for a vertically mounted Venturi meter

    International Nuclear Information System (INIS)

    Xu, Lijun; Zhou, Wanlu; Li, Xiaomin

    2012-01-01

    Venturi meters are playing an increasingly important role in wet gas metering in natural gas and oil industries. Due to the effect of liquid in a wet gas, the differential pressure over the converging section of a Venturi meter is higher than that when a pure gas flows through with the same flow rate. This phenomenon is referred to as over-reading. Thus, a correction for the over-reading is required. Most of the existing wet gas models are more suitable for higher pressure (>2 MPa) than lower pressure ( 0.5) than lower quality (<0.5) in recent years. However, conditions of lower pressure and lower quality also widely exist in the gas and oil industries. By comparing the performances of eight existing wet gas models in low-pressure range of 0.26–0.86 MPa and low-quality range of 0.07–0.36 with a vertically mounted Venturi meter of diameter ratio 0.45, de Leeuw's model was proven to perform best. Derived from de Leeuw's model, a modified model with better performance for the low-pressure and low-quality ranges was obtained. Experimental data showed that the root mean square of the relative errors of the over-reading was 2.30%. (paper)

  10. Simulation, integration, and economic analysis of gas-to-liquid processes

    International Nuclear Information System (INIS)

    Bao, Buping; El-Halwagi, Mahmoud M.; Elbashir, Nimir O.

    2010-01-01

    Gas-to-liquid (GTL) involves the chemical conversion of natural gas into synthetic crude that can be upgraded and separated into different useful hydrocarbon fractions including liquid transportation fuels. Such technology can also be used to convert other abundant natural resources such as coal and biomass to fuels and value added chemicals (referred to as coal-to-liquid (CTL) and biomass-to-liquid (BTL)). A leading GTL technology is the Fischer-Tropsch (FT) process. The objective of this work is to provide a techno-economic analysis of the GTL process and to identify optimization and integration opportunities for cost saving and reduction of energy usage while accounting for the environmental impact. First, a base-case flowsheet is synthesized to include the key processing steps of the plant. Then, a computer-aided process simulation is carried out to determine the key mass and energy flows, performance criteria, and equipment specifications. Next, energy and mass integration studies are performed to address the following items: (a) heating and cooling utilities, (b) combined heat and power (process cogeneration), (c) management of process water, (c) optimization of tail gas allocation, and (d) recovery of catalyst-supporting hydrocarbon solvents. Finally, these integration studies are conducted and the results are documented in terms of conserving energy and mass resources as well as providing economic impact. Finally, an economic analysis is undertaken to determine the plant capacity needed to achieve the break-even point and to estimate the return on investment for the base-case study. (author)

  11. Local composition shift of mixed working fluid in gas–liquid flow with phase transition

    International Nuclear Information System (INIS)

    Xu Xiongwen; Liu Jinping; Cao Le; Li Zeyu

    2012-01-01

    Local composition shift is an important characteristic of gas-liquid mixture flow with phase transition. It affects the heat transfer process, stream sonic velocity and the mixture distribution in the thermodynamic cycle. Presently, it is mainly calculated through the empirical models of the void fraction from pure fluid experiments. In this paper, we made efforts to obtain it and its rules basing on conservation equations derivation. The result calculated with propane/i-butane binary mixture was verified by the experiment in the evaporator of a refrigerator. As an extending, it was applied to a ternary mixture with components of methane, propane and butane and more information was presented and analyzed. The calculation approach presented in this paper can be applied any multicomponent mixture, and the rules will be helpful to improve the composition shift theory. - Highlights: ► Local composition shift of mixed working fluid in gas–liquid flow was modelled. ► A solution method for local composition of gas–liquid flow was proposed. ► The solution method was verified by the experimental result. ► Local composition shift mechanism of gas–liquid flow was studied

  12. Gas-Liquid Separator design of SWRPRS in PGSFR

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jung; Lee, Tae-ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    There is the Sodium-Water Reaction Pressure Relief System (SWRPRS) in PGSFR to prevent the Sodium- Water Reaction (SWR) due to the break of the steam generator tube. The piping to atmosphere includes several components such as gasliquid separator, backpressure rupture disk, and hydrogen igniter. Among these components, gas-liquid separator separates the liquid sodium which is included in gas SWR products not to react sodium and air. In this study, the size of gas-liquid separator, which is based on the hydrogen volume which is exhausted in the sodium dump tank, is determined. To determine the gas-liquid separator for the separation of gas and sodium particle dumped the SDT, Stairmand's model which has high performance among standard cyclone separator models is selected. The body diameter is determined, and other dimensions are determined due to the ratio about the body diameter. Shepherd and Lapple's model is selected as the pressure drop calculation model considering the conservation.

  13. Numerical modeling of turbulent evaporating gas-droplet two-phase flows in an afterburner diffusor of turbo-fan jet engines

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Lixing; Zhang, Jian [Qinghua Univ., Beijing (China)

    1990-11-01

    Two-dimensional turbulent evaporating gas-droplet two-phase flows in an afterburner diffusor of turbofan jet engines are simulated here by a k-epsilon turbulence model and a particle trajectory model. Comparison of predicted gas velocity and temperature distributions with experimental results for the cases without liquid spray shows good agreement. Gas-droplet two-phase flow predictions give plausible droplet trajectories, fuel-vapor concentration distribution, gas-phase velocity and temperature field in the presence of liquid droplets. One run of computation with this method is made for a particular afterburner. The results indicate that the location of the atomizers is not favorable to flame stabilization and combustion efficiency. The proposed numerical modeling can also be adopted for optimization design and performance evaluation of afterburner combustors of turbofan jet engines. 7 refs.

  14. CFD simulation of gas and non-Newtonian fluid two-phase flow in anaerobic digesters.

    Science.gov (United States)

    Wu, Binxin

    2010-07-01

    This paper presents an Eulerian multiphase flow model that characterizes gas mixing in anaerobic digesters. In the model development, liquid manure is assumed to be water or a non-Newtonian fluid that is dependent on total solids (TS) concentration. To establish the appropriate models for different TS levels, twelve turbulence models are evaluated by comparing the frictional pressure drops of gas and non-Newtonian fluid two-phase flow in a horizontal pipe obtained from computational fluid dynamics (CFD) with those from a correlation analysis. The commercial CFD software, Fluent12.0, is employed to simulate the multiphase flow in the digesters. The simulation results in a small-sized digester are validated against the experimental data from literature. Comparison of two gas mixing designs in a medium-sized digester demonstrates that mixing intensity is insensitive to the TS in confined gas mixing, whereas there are significant decreases with increases of TS in unconfined gas mixing. Moreover, comparison of three mixing methods indicates that gas mixing is more efficient than mixing by pumped circulation while it is less efficient than mechanical mixing.

  15. Local measurement of interfacial area, interfacial velocity and liquid turbulence in two-phase flow

    International Nuclear Information System (INIS)

    Hibiki, T.; Hogsett, S.; Ishii, M.

    1998-01-01

    Double sensor probe and hotfilm anemometry methods were developed for measuring local flow characteristics in bubbly flow. The formulation for the interfacial area concentration measurement was obtained by improving the formulation derived by Kataoka and Ishii. The assumptions used in the derivation of the equation were verified experimentally. The interfacial area concentration measured by the double sensor probe agreed well with one by the photographic method. The filter to validate the hotfilm anemometry for measuring the liquid velocity and turbulent intensity in bubbly flow was developed based on removing the signal due to the passing bubbles. The local void fraction, interfacial area concentration, interfacial velocity, Sauter mean diameter, liquid velocity, and turbulent intensity of vertical upward air-water flow in a round tube with inner diameter of 50.8 mm were measured by using these methods. A total of 54 data sets were acquired consisting of three superficial gas flow rates, 0.039, 0.067, and 0.147 m/s, and three superficial liquid flow rates, 0.60, 1.00, and 1.30 m/s. The measurements were performed at the three locations: L/D=2, 32, and 62. This data is expected to be used for the development of reliable constitutive relations which reflect the true transfer mechanisms in two-phase flow. (author)

  16. Gas--liquid equilibria in mixtures of hydrogen and thianaphthene

    Energy Technology Data Exchange (ETDEWEB)

    Sebastian, H M; Simnick, J J; Lin, H M; Chao, K C

    1978-12-01

    Gas--liquid equilibrium conditions in binary mixtures of hydrogen and thianaphthene were experimentally determined at temperature of 190 to 430/sup 0/C and pressures to 250 atm in a flow apparatus. The same apparatus was also employed to measure the vapor pressure of thianaphthene. Comparisons of the new mixture data with Chao--Seader and Grayson--Streed correlations show that both correlations predict the thianaphthene equilibrium ratios well but are in error by up to about 45 and 35% respectively for K-values of hydrogen. 4 figures, 2 tables.

  17. Spray flow-network flow transition of binary Lennard-Jones particle system

    KAUST Repository

    Inaoka, Hajime

    2010-07-01

    We simulate gas-liquid flows caused by rapid depressurization using a molecular dynamics model. The model consists of two types of Lennard-Jones particles, which we call liquid particles and gas particles. These two types of particles are distinguished by their mass and strength of interaction: a liquid particle has heavier mass and stronger interaction than a gas particle. By simulations with various initial number densities of these particles, we found that there is a transition from a spray flow to a network flow with an increase of the number density of the liquid particles. At the transition point, the size of the liquid droplets follows a power-law distribution, while it follows an exponential distribution when the number density of the liquid particles is lower than the critical value. The comparison between the transition of the model and that of models of percolation is discussed. The change of the average droplet size with the initial number density of the gas particles is also presented. © 2010 Elsevier B.V. All rights reserved.

  18. Spray flow-network flow transition of binary Lennard-Jones particle system

    KAUST Repository

    Inaoka, Hajime; Yukawa, Satoshi; Ito, Nobuyasu

    2010-01-01

    We simulate gas-liquid flows caused by rapid depressurization using a molecular dynamics model. The model consists of two types of Lennard-Jones particles, which we call liquid particles and gas particles. These two types of particles are distinguished by their mass and strength of interaction: a liquid particle has heavier mass and stronger interaction than a gas particle. By simulations with various initial number densities of these particles, we found that there is a transition from a spray flow to a network flow with an increase of the number density of the liquid particles. At the transition point, the size of the liquid droplets follows a power-law distribution, while it follows an exponential distribution when the number density of the liquid particles is lower than the critical value. The comparison between the transition of the model and that of models of percolation is discussed. The change of the average droplet size with the initial number density of the gas particles is also presented. © 2010 Elsevier B.V. All rights reserved.

  19. The spray characteristic of gas-liquid coaxial swirl injector by experiment

    Directory of Open Access Journals (Sweden)

    Chen Chen

    2017-01-01

    Full Text Available Using the laser phase Doppler particle analyzer (PDPA, the spray characteristics of gas-liquid coaxial swirl injector were studied. The Sauter mean diameter (SMD, axial velocity and size data rate were measured under different gas injecting pressure drop and liquid injecting pressure drop. Comparing to a single liquid injection, SMD with gas presence is obviously improved. So the gas presence has a significant effect on the atomization of the swirl injector. What’s more, the atomization effect of gas-liquid is enhanced with the increasing of the gas pressure drop. Under the constant gas pressure drop, the injector has an optimal liquid pressure drop under which the atomization performance is best.

  20. Gas-liquid hybrid discharge-induced degradation of diuron in aqueous solution.

    Science.gov (United States)

    Feng, Jingwei; Zheng, Zheng; Luan, Jingfei; Li, Kunquan; Wang, Lianhong; Feng, Jianfang

    2009-05-30

    Degradation of diuron in aqueous solution by gas-liquid hybrid discharge was investigated for the first time. The effect of output power intensity, pH value, Fe(2+) concentration, Cu(2+) concentration, initial conductivity and air flow rate on the degradation efficiency of diuron was examined. The results showed that the degradation efficiency of diuron increased with increasing output power intensity and increased with decreasing pH values. In the presence of Fe(2+), the degradation efficiency of diuron increased with increasing Fe(2+) concentration. The degradation efficiency of diuron was decreased during the first 4 min and increased during the last 10 min with adding of Cu(2+). Decreasing the initial conductivity and increasing the air flow rate were favorable for the degradation of diuron. Degradation of diuron by gas-liquid hybrid discharge fitted first-order kinetics. The pH value of the solution decreased during the reaction process. Total organic carbon removal rate increased in the presence of Fe(2+) or Cu(2+). The generated Cl(-1), NH(4)(+), NO(3)(-), oxalic acid, acetic acid and formic acid during the degradation process were also detected. Based on the detected Cl(-1) and other intermediates, a possible degradation pathway of diuron was proposed.

  1. Options for Gas-to-Liquids Technology in Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Eric Partridge

    1999-10-01

    The purposes of this work was to assess the effect of applying new technology to the economics of a proposed natural gas-to-liquids (GTL) plant, to evaluate the potential of a slower-paced, staged deployment of GTL technology, and to evaluate the effect of GTL placement of economics. Five scenarios were economically evaluated and compared: a no-major-gas-sales scenario, a gas-pipeline/LNG scenario, a fast-paced GTL development scenario, a slow-paced GTL development scenario, and a scenario which places the GTL plant in lower Alaska, instead of on the North Slope. Evaluations were completed using an after-tax discounted cash flow analysis. Results indicate that the slow-paced GTL scenario is the only one with a rate of return greater than 10 percent. The slow-paced GTL development would allow cost saving on subsequent expansions. These assumed savings, along with the lowering of the transportation tariff, combine to distinquish this option for marketing the North Slope gas from the other scenarios. Critical variables that need further consideration include the GTL plant cost, the GTL product premium, and operating and maintenance costs.

  2. Effect of stratified inequality of blood flow on gas exchange in liquid-filled lungs.

    Science.gov (United States)

    West, J. B.; Maloney, J. E.; Castle, B. L.

    1972-01-01

    This investigation set out to answer two questions: (1) are the distal alveoli in the terminal lung units less well perfused than the proximal alveoli, i.e., is there stratification of blood flow; and (2) if so, does this enhance gas exchange in the presence of stratified inequality of ventilation. Excised dog lungs were ventilated with saline and perfused with blood. Following single inspirations of xenon 133 in saline and various periods of breath holding, the expired xenon concentration against volume was measured and it confirmed marked stratified inequality of ventilation under these conditions. By measuring the rate of depletion of xenon from alveoli during a period of blood flow, we showed that the alveoli which emptied at the end of expiration had 16% less blood flow than those exhaling earlier. However, by measuring the xenon concentration in pulmonary venous blood, we found that about 10% less tracer was transferred from the alveoli into the blood when the inspired xenon was stratified within the respiratory zone. Thus while stratification of blood flow was confirmed, it was shown to impair rather than enhance the efficiency of gas transfer.

  3. Modelling of Churn-Annular foam flows

    NARCIS (Netherlands)

    Westende, J.M.C. van 't; Shoeibi Omrani, P.; Vercauteren, F.F.; Nennie, E.D.

    2016-01-01

    Foam assisted lift is a deliquification method in the oil and gas industry, which aims to prevent or postpone countercurrent gas-liquid flow in maturing gas wells or to assist in removing downhole accumulated liquids. According to Nimwegen, who performed experiments with foam flows, foam

  4. Problems of hydrogen - water vapor - inert gas mixture use in heavy liquid metal coolant technology

    International Nuclear Information System (INIS)

    Ul'yanov, V.V.; Martynov, P.N.; Gulevskij, V.A.; Teplyakov, Yu.A.; Fomin, A.S.

    2014-01-01

    The reasons of slag deposit formation in circulation circuits with heavy liquid metal coolants, which can cause reactor core blockage, are considered. To prevent formation of deposits hydrogen purification of coolant and surfaces of circulation circuit is used. It consists in introduction of gaseous mixtures hydrogen - water vapor - rare gas (argon or helium) directly into coolant flow. The principle scheme of hydrogen purification and the processes occurring during it are under consideration. Measures which make it completely impossible to overlap of the flow cross section of reactor core, steam generators, pumps and other equipment by lead oxides in reactor facilities with heavy liquid metal coolants are listed [ru

  5. Modeling and simulation of a pseudo-two-phase gas-liquid column reactor for thermal hydrocracking of petroleum heavy fractions

    Directory of Open Access Journals (Sweden)

    E.M. Matos

    2002-07-01

    Full Text Available This work presents a model to predict the behavior of velocity, gas holdup and local concentration fields in a pseudo-two-phase gas-liquid column reactor applied for thermal hydrocracking of petroleum heavy fractions. The model is based on the momentum and mass balances for the system, using an Eulerian-Eulerian approach. Using the k-epsilon model,fluid dynamics accounts for both laminar and turbulent flows, with discrete small bubbles (hydrogen flowing in a continuous pseudohomogeneous liquid phase (oil and catalyst particles. The petroleum is assumed to be a mixture of pseudocomponents, grouped by similar chemical structural properties, and the thermal hydrocracking is taken into account using a kinetic network based on these pseudocomponents.

  6. Natural gas liquids: market outlook

    International Nuclear Information System (INIS)

    Heath, M.

    1996-01-01

    Future market outlook for natural gas liquids was discussed. It was shown that Canadian natural gas and natural gas liquid (NGL) production levels have experienced extraordinary growth over the past few years due to an increased U.S. demand for Canadian natural gas. Recent supply and demand studies have indicated that there will be growing surpluses of NGLs in Canada. By 1996, the majority of NGL surplus that is forecast to be available is ethane (64%), followed by propane (22%), butane (12%) and pentane plus (2%). Throughout the forecast period, the ratio of incremental ethane to the total NGL surplus, over and above forecast demand, was expected to continue to rise. The viability of producing and processing that ethane and transporting it to market, will be crucial. Development of a large ex-Alberta C2+ pipeline from Empress to Mont Belvieu under the reference case supply projection is a possibility, but only if total tariff and fractionation charge on the line is less than or equal to 10 US cents/USG (currently 16-22 US cents/USG). 11 figs

  7. A transit-time flow meter for measuring milliliter per minute liquid flow

    DEFF Research Database (Denmark)

    Yang, Canqian; Kymmel, Mogens; Søeberg, Henrik

    1988-01-01

    A transit-time flow meter, using periodic temperature fluctuations as tracers, has been developed for measuring liquid flow as small as 0.1 ml/min in microchannels. By injecting square waves of heat into the liquid flow upstream with a tiny resistance wire heater, periodic temperature fluctuation....... This flow meter will be used to measure and control the small liquid flow in microchannels in flow injection analysis. Review of Scientific Instruments is copyrighted by The American Institute of Physics....... are generated downstream. The fundamental frequency phase shift of the temperature signal with respect to the square wave is found to be a linear function of the reciprocal mean velocity of the fluid. The transit-time principle enables the flow meter to have high accuracy, better than 0.2%, and good linearity...

  8. Characterization of the external and internal flow structure of an aerated-liquid injector using X-ray radiography and fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Peltier, Scott J.; Lin, Kuo-Cheng; Carter, Campbell D.; Kastengren, Alan L.

    2017-08-02

    In the present study, the internal flowfield of aerated-liquid fuel injectors is examined through x-ray radiography and x-ray fluorescence. An inside-out injector, consisting of a perforated aerating tube within an annular liquid stream, sprays into a quiescent environment at a fixed mass flow rate of water and nitrogen gas. The liquid is doped with bromine (in the form of NaBr) to create an x-ray fluorescence signal. This allows for reasonable absorption and fluorescence signals, and one or both diagnostics can be used to track the liquid distribution. The injector housing is fabricated from beryllium (Be), which allows the internal flowfield to be examined (as Be has relatively low x-ray attenuation coefficient). Two injector geometries are compared, illustrating the effects of aerating orifice size and location on the flow evolution. Time-averaged equivalent pathlength (EPL) and line-of-sight averaged density ρ(y) reveal the formation of the two-phase mixture, showing that the liquid film thickness along the injector walls is a function of the aerating tube geometry, though only upstream of the nozzle. These differences in gas and liquid distribution (between injectors with different aerating tube designs) are suppressed as the mixture traverses the nozzle contraction. The averaged liquid velocity (computed from the density and liquid mass flow rate) reveal a similar trend. This suggests that at least for the current configurations, the plume width, liquid mass distribution, and averaged liquid velocity for the time-averaged external spray are insensitive to the aerating tube geometry.

  9. Characterization of the external and internal flow structure of an aerated-liquid injector using X-ray radiography and fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Peltier, Scott J. [Aerospace Systems Directorate, Air Force Research Laboratory, Arnold AFB, TN (United States); Lin, Kuo-Cheng [Taitech, Inc., Beavercreek, OH (United States); Carter, Campbell D. [Aerospace Systems Directorate, Air Force Research Laboratory, Wright-Patterson AFB, OH (United States); Kastengren, Alan L. [Argonne National Laboratory, X-Ray Science Division, Advanced Photon Source, Argonne, IL (United States)

    2017-09-15

    In the present study, the internal flowfield of aerated-liquid fuel injectors is examined through X-ray radiography and X-ray fluorescence. An inside-out injector, consisting of a perforated aerating tube within an annular liquid stream, sprays into a quiescent environment at a fixed mass flow rate of water and nitrogen gas. The liquid is doped with bromine (in the form of NaBr) to create an X-ray fluorescence signal. This allows for reasonable absorption and fluorescence signals, and one or both diagnostics can be used to track the liquid distribution. The injector housing is fabricated from beryllium (Be), which allows the internal flowfield to be examined (as Be has relatively low X-ray attenuation coefficient). Two injector geometries are compared, illustrating the effects of aerating orifice size and location on the flow evolution. Time-averaged equivalent pathlength and line-of-sight averaged density ρ(y) reveal the formation of the two-phase mixture, showing that the liquid film thickness along the injector walls is a function of the aerating tube geometry, though only upstream of the nozzle. These differences in gas and liquid distribution (between injectors with different aerating tube designs) are suppressed as the mixture traverses the nozzle contraction. The averaged liquid velocity (computed from the density and liquid mass flow rate) reveals a similar trend. This suggests that at least for the current configurations, the plume width, liquid mass distribution, and averaged liquid velocity for the time-averaged external spray are insensitive to the aerating tube geometry. (orig.)

  10. Liquid velocity in upward and downward air-water flows

    International Nuclear Information System (INIS)

    Sun Xiaodong; Paranjape, Sidharth; Kim, Seungjin; Ozar, Basar; Ishii, Mamoru

    2004-01-01

    Local characteristics of the liquid phase in upward and downward air-water two-phase flows were experimentally investigated in a 50.8-mm inner-diameter round pipe. An integral laser Doppler anemometry (LDA) system was used to measure the axial liquid velocity and its fluctuations. No effect of the flow direction on the liquid velocity radial profile was observed in single-phase liquid benchmark experiments. Local multi-sensor conductivity probes were used to measure the radial profiles of the bubble velocity and the void fraction. The measurement results in the upward and downward two-phase flows are compared and discussed. The results in the downward flow demonstrated that the presence of the bubbles tended to flatten the liquid velocity radial profile, and the maximum liquid velocity could occur off the pipe centerline, in particular at relatively low flow rates. However, the maximum liquid velocity always occurred at the pipe center in the upward flow. Also, noticeable turbulence enhancement due to the bubbles in the two-phase flows was observed in the current experimental flow conditions. Furthermore, the distribution parameter and the void-weighted area-averaged drift velocity were obtained based on the definitions

  11. Scaling relation and regime map of explosive gas–liquid flow of binary Lennard-Jones particle system

    KAUST Repository

    Inaoka, Hajime; Yukawa, Satoshi; Ito, Nobuyasu

    2012-01-01

    liquid droplets, and gas particles, which remain supercritical gaseous states under the depressurization realized by simulations. The system has a pipe-like structure similar to the model of a shock tube. We observed physical quantities and flow regimes

  12. Solid and liquid 129Xe NMR signals enhanced by spin-exchange optical pumping under flow

    International Nuclear Information System (INIS)

    Zhou Xin; Luo Jun; Sun Xianping; Zeng Xizhi; Liu Maili; Liu Wuyang

    2002-01-01

    Laser-polarized 129 Xe gas was produced by spin-exchange with Cs atom optically pumped with diode laser array in a low field under flow. The nuclear spin polarizations of the solid and liquid 129 Xe frozen from the laser-polarized 129 Xe gas were 2.16% and 1.45% respectively in the SY-80M NMR spectrometer, which corresponded to the enhancements of 6000 and 5000 compared to those without optical pumping under the same conditions. It could provide the base and possibility for quantum computers using laser-enhanced solid and liquid 129 Xe. Polarization loss of transport and state change was also discussed

  13. Single-phase and two-phase gas-liquid turbulent mixing between subchannels in a simulated rod bundle

    International Nuclear Information System (INIS)

    Sadatomi, Michio; Kawahara, Akimaro; Sato, Yoshifusa; Tomino, Takayoshi.

    1996-01-01

    This study is concerned with turbulent mixing which is one of the three mechanisms of cross flows between subchannels in a nuclear fuel rod bundle. The channel used in this experiments was a vertical simulated rod bundle having two subchannels connected through 1 to 3 gaps between two rods and/or rod and channel wall. The number of the gaps was changed to investigate the effect of the number on the turbulent mixing. Turbulent mixing rates of air and water and fluctuations of pressure difference between the subchannels were measured for single-phase and two-phase gas-liquid flows under hydrodynamic equilibrium flow conditions. It has been confirmed that the turbulent mixing rate is affected strongly by the fluctuations especially for liquid phase in two-phase slug or churn flow. (author)

  14. Mathematical Investigation of Fluid Flow, Mass Transfer, and Slag-steel Interfacial Behavior in Gas-stirred Ladles

    Science.gov (United States)

    Cao, Qing; Nastac, Laurentiu

    2018-06-01

    In this study, the Euler-Euler and Euler-Lagrange modeling approaches were applied to simulate the multiphase flow in the water model and gas-stirred ladle systems. Detailed comparisons of the computational and experimental results were performed to establish which approach is more accurate for predicting the gas-liquid multiphase flow phenomena. It was demonstrated that the Euler-Lagrange approach is more accurate than the Euler-Euler approach. The Euler-Lagrange approach was applied to study the effects of the free surface setup, injected bubble size, gas flow rate, and slag layer thickness on the slag-steel interaction and mass transfer behavior. Detailed discussions on the flat/non-flat free surface assumption were provided. Significant inaccuracies in the prediction of the surface fluid flow characteristics were found when the flat free surface was assumed. The variations in the main controlling parameters (bubble size, gas flow rate, and slag layer thickness) and their potential impact on the multiphase fluid flow and mass transfer characteristics (turbulent intensity, mass transfer rate, slag-steel interfacial area, flow patterns, etc.,) in gas-stirred ladles were quantitatively determined to ensure the proper increase in the ladle refining efficiency. It was revealed that by injecting finer bubbles as well as by properly increasing the gas flow rate and the slag layer thickness, the ladle refining efficiency can be enhanced significantly.

  15. X-ray scattering on liquid-gas interfaces; Roentgenstreuung an Fluessigkeits-Gas Grenzflaechen

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, Michael

    2006-07-01

    In the framework of this thesis two different theme-fields were studied with dhe methods of the elastic, surface sensitive X-ray scattering. In the first part of the thesis the liquid-gas interfaces water-propane and glycerol-isobutane were studied concerning the structure formation on these interfaces. The system water-propane served for the study of the gas hydrate formation on the water-gas interface. Studies on this interface could give no hints on the formation of propane hydrates or propane-hydrate fragments. However the adsorption of molecularly thin propane films on the water surface was observed. The adsorption behaviour of gases on liquid surfaces was studied by further experiments on the glycerol-isobutane interface. In the second part of the thesis the surfaces of aqueous salt solutions and water were studied. The lateralstructure of these liquid-gas interfaces was studied by the method of the diffuse X-ray scattering.

  16. Flow boiling heat transfer at low liquid Reynolds number

    International Nuclear Information System (INIS)

    Weizhong Zhang; Takashi Hibiki; Kaichiro Mishima

    2005-01-01

    Full text of publication follows: In view of the significance of a heat transfer correlation of flow boiling at conditions of low liquid Reynolds number or liquid laminar flow, and very few existing correlations in principle suitable for such flow conditions, this study is aiming at developing a heat transfer correlation of flow boiling at low liquid Reynolds number conditions. The obtained results are as follows: 1. A new heat transfer correlation has been developed for saturated flow boiling at low liquid Reynolds number conditions based on superimposition of two boiling mechanisms, namely convective boiling and nucleate boiling. In the new correlation, two terms corresponding to the mechanisms of nucleate boiling and convective boiling are obtained from the pool boiling correlation by Forster and Zuber and the analytical annular flow model by Hewitt and Hall-Taylor, respectively. 2. An extensive database was collected for saturated flow boiling heat transfer at low liquid Reynolds number conditions, including data for different channels geometries (circular and rectangular), flow orientations (vertical and horizontal), and working fluids (water, R11, R12, R113). 3. An extensive comparison of the new correlation with the collected database shows that the new correlation works satisfactorily with the mean deviation of 16.6% for saturated flow boiling at low liquid Reynolds number conditions. 4. The detailed discussion reveals the similarity of the newly developed correlation for flow boiling at low liquid Reynolds number to the Chen correlation for flow boiling at high liquid Reynolds number. The Reynolds number factor F can be analytically deduced in this study. (authors)

  17. Gas Marbles: Much Stronger than Liquid Marbles

    Science.gov (United States)

    Timounay, Yousra; Pitois, Olivier; Rouyer, Florence

    2017-06-01

    Enwrapping liquid droplets with hydrophobic particles allows the manufacture of so-called "liquid marbles" [Aussillous and Quéré Nature (London) 411, 924 (2001); , 10.1038/35082026Mahadevan Nature (London)411, 895 (2001), 10.1038/35082164]. The recent intensive research devoted to liquid marbles is justified by their very unusual physical and chemical properties and by their potential for various applications, from microreactors to water storage, including water pollution sensors [Bormashenko Curr. Opin. Colloid Interface Sci. 16, 266 (2011), 10.1016/j.cocis.2010.12.002]. Here we demonstrate that this concept can be successfully applied for encapsulating and protecting small gas pockets within an air environment. Similarly to their liquid counterparts, those new soft-matter objects, that we call "gas marbles," can sustain external forces. We show that gas marbles are surprisingly tenfold stronger than liquid marbles and, more importantly, they can sustain both positive and negative pressure differences. This magnified strength is shown to originate from the strong cohesive nature of the shell. Those interesting properties could be exploited for imprisoning valuable or polluted gases or for designing new aerated materials.

  18. Radial flow gas dynamic laser

    International Nuclear Information System (INIS)

    Damm, F.C.

    1975-01-01

    The unique gas dynamic laser provides outward radial supersonic flow from a toroidal shaped stacked array of a plurality of nozzles, through a diffuser having ring shaped and/or linear shaped vanes, and through a cavity which is cylindrical and concentric with the stacked array, with the resultant laser beam passing through the housing parallel to the central axis of the diffuser which is coincident with the axis of the gas dynamic laser. Therefore, greater beam extraction flexibility is attainable, because of fewer flow shock disturbances, as compared to the conventional unidirectional flow gas dynamic laser in which unidirectional supersonic flow sweeps through a rectangular cavity and is exhausted through a two-dimensional diffuser. (auth)

  19. 1st European Conference on Gas Micro Flows (GasMems 2012)

    NARCIS (Netherlands)

    Frijns, A.J.H.; Valougeorgis, D.; Colin, S.; Baldas, L.

    2012-01-01

    PREFACE The aim of the 1st European Conference on Gas Micro Flows is to advance research in Europe and worldwide in the field of gas micro flows as well as to improve global fundamental knowledge and to enable technological applications. Gas flows in microsystems are of great importance and touch

  20. Liquid films and droplet deposition in a BWR fuel element

    International Nuclear Information System (INIS)

    Damsohn, M.

    2011-01-01

    In the upper part of boiling water reactors (BWR) the flow regime is dominated by a steam-water droplet flow with liquid films on the nuclear fuel rod, the so called (wispy) annular flow regime. The film thickness and liquid flow rate distribution around the fuel rod play an important role especially in regard to so called dryout, which is the main phenomenon limiting the thermal power of a fuel assembly. The deposition of droplets in the liquid film is important, because this process sustains the liquid film and delays dryout. Functional spacers with different vane shapes have been used in recent decades to enhance droplet deposition and thus create more favorable conditions for heat removal. In this thesis the behavior of liquid films and droplet deposition in the annular flow regime in BWR bundles is addressed by experiments in an adiabatic flow at nearly ambient pressure. The experimental setup consists of a vertical channel with the cross-section resembling a pair of neighboring subchannels of a fuel rod bundle. Within this double subchannel an annular flow is established with a gas-water mixture. The impact of functional spacers on the annular flow behavior is studied closely. Parameter variations comprise gas and liquid flow rates, gas density and spacer shape. The setup is instrumented with a newly developed liquid film sensor that measures the electrical conductance between electrodes flush to the wall with high temporal and spatial resolution. Advanced post-processing methods are used to investigate the dynamic behavior of liquid films and droplet deposition. The topic is also assessed numerically by means of single-phase Reynolds-Averaged-Navier-Stokes CFD simulations of the flow in the gas core. For this the commercial code STAR-CCM+ is used coupled with additional models for the liquid film distribution and droplet motion. The results of the experiments show that the liquid film is quite evenly distributed around the circumference of the fuel rods. The

  1. Gas-liquid reactor / separator: dynamics and operability characteristics

    NARCIS (Netherlands)

    Ranade, V.; Kuipers, J.A.M.; Versteeg, Geert

    1999-01-01

    A comprehensive mathematical model is developed to simulate gas¿liquid reactor in which both, reactants as well as products enter or leave the reactor in gas phase while the reactions take place in liquid phase. A case of first-order reaction (isothermal) was investigated in detail using the dynamic

  2. Effects of respiratory rate and tidal volume on gas exchange in total liquid ventilation.

    Science.gov (United States)

    Bull, Joseph L; Tredici, Stefano; Fujioka, Hideki; Komori, Eisaku; Grotberg, James B; Hirschl, Ronald B

    2009-01-01

    Using a rabbit model of total liquid ventilation (TLV), and in a corresponding theoretical model, we compared nine tidal volume-respiratory rate combinations to identify a ventilator strategy to maximize gas exchange, while avoiding choked flow, during TLV. Nine different ventilation strategies were tested in each animal (n = 12): low [LR = 2.5 breath/min (bpm)], medium (MR = 5 bpm), or high (HR = 7.5 bpm) respiratory rates were combined with a low (LV = 10 ml/kg), medium (MV = 15 ml/kg), or high (HV = 20 ml/kg) tidal volumes. Blood gases and partial pressures, perfluorocarbon gas content, and airway pressures were measured for each combination. Choked flow occurred in all high respiratory rate-high volume animals, 71% of high respiratory rate-medium volume (HRMV) animals, and 50% of medium respiratory rate-high volume (MRHV) animals but in no other combinations. Medium respiratory rate-medium volume (MRMV) resulted in the highest gas exchange of the combinations that did not induce choke. The HRMV and MRHV animals that did not choke had similar or higher gas exchange than MRMV. The theory predicted this behavior, along with spatial and temporal variations in alveolar gas partial pressures. Of the combinations that did not induce choked flow, MRMV provided the highest gas exchange. Alveolar gas transport is diffusion dominated and rapid during gas ventilation but is convection dominated and slow during TLV. Consequently, the usual alveolar gas equation is not applicable for TLV.

  3. Thermal behaviour of agitated gas-liquid reactors with a vaporizing solvent/air oxidation of hydrocarbons

    NARCIS (Netherlands)

    Westerterp, K.R.; Crombeen, P.R.J.J.

    1983-01-01

    Many highly exothermic gas-liquid reactions are carried out with a vaporizing solvent, which after condensation is returned to the reactor. In this way the liberated reaction heat for a large part is absorbed by the cooling water flowing through the condenser. In order to determine the influence of

  4. The influence of pH on gas-liquid mass transfer in non-Newtonian fluids

    OpenAIRE

    Li Shaobai; Fan Jungeng; Xu Shuang; Li Rundong; Luan Jingde

    2017-01-01

    In this study, the effect of pH on the mass transfer of oxygen bubble swarms in non-Newtonian fluids was experimentally studied. The volumetric liquid side mass transfer coefficient (kLa), liquid side mass transfer coefficient (kL), and specific interfacial area (a) were investigated. The pH was regulated by the addition of hydrochloric acid and sodium hydroxide (NaOH). It was found that the kLa increased with the gas flow rate increasing and decreased with the apparent viscosity of the liqui...

  5. The effect of geometry and operation conditions on the performance of a gas-liquid cylindrical cyclone separator with new structure

    Science.gov (United States)

    Han, Qing; Zhang, Chi; Xu, Bo; Chen, Jiangping

    2013-07-01

    The hydrodynamic flow behavior, effects of geometry and working conditions of a gas-liquid cylindrical cyclone separator with a new structure are investigated by computational fluid dynamic and experiment. Gas liquid cylindrical cyclone separator is widely used in oil industry, refrigeration system because of its simple structure, high separating efficiency, little maintenance and no moving parts nor internal devices. In this work, a gas liquid cylindrical cyclone separator with new structure used before evaporator in refrigeration system can remove the vapor from the mixture and make evaporator compact by improving its heat exchange efficiency with the lower inlet quality. It also decreases evaporator pressure drop and reduces compressor work. The two pipes are placed symmetrically which makes each of them can be treated as inlet. It means when the fluids flow reverse, the separator performance will not be influence. Four samples with different geometry parameters are tested by experiment with different inlet quality (0.18-0.33), inlet mass flow rate (65-100kg/h). Compared with the experimental data, CFD simulation results show a good agreement. Eulerian multiphase model and Reynolds Stress Turbulence model are applied in the CFD simulation and obtained the inner flow field such as phase path lines, tangential velocity profiles and pressure and volume of fraction distribution contours. The separator body diameter (24, 36, 48mm) and inlet diameter (3.84, 4.8, 5.76mm) decide the maximum tangential velocity which results in the centrifugal force. The tangential velocity profiles are simulated and compared among different models. The higher tangential velocity makes higher quality of gas outlet but high pressure drop at the same time. Decreasing the inlet diameter increases quality of gas outlet pipe and pressure drop. High gas outlet quality is cost at high pressure drop. Increasing of separator diameter makes gas outlet quality increase first and then decrease but

  6. Liquid film characterization in horizontal, annular, two-phase, gas-liquid flow using time-resolved laser-induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Farias, P.S.C.; Martins, F.J.W.A.; Azevedo, L.F.A. [PUC-Rio, Department of Mechanical Engineering, Rio de Janeiro (Brazil); Sampaio, L.E.B. [LMTA/PGMEC, UFF, Department of Mechanical Engineering, Laboratory of Theoretical and Applied Mechanics, Rio de Janeiro (Brazil); Serfaty, R. [Petrobras R and D Center, Rio de Janeiro (Brazil)

    2012-03-15

    A non-intrusive optical technique was developed to provide time-resolved longitudinal and cross-sectional images of the liquid film in horizontal annular pipe flow of air and water, revealing the interfacial wave behavior. Quantitative information on the liquid film dynamics was extracted from the time-resolved images. The planar laser-induced fluorescence technique was utilized to allow for optical separation of the light emitted by the film from that scattered by the air-water interface. The visualization test section was fabricated from a tube presenting nearly the same refractive index as water, which allowed the visualization of the liquid film at regions very close to the pipe wall. Longitudinal images of the liquid film were captured using a high-frame-rate digital video camera synchronized with a high-repetition-rate laser. An image processing algorithm was developed to automatically detect the position of the air-water interface in each image frame. The thickness of the liquid film was measured at two axial stations in each processed image frame, providing time history records of the film thickness at two different positions. Wave frequency information was obtained by analyzing the time-dependent signals of film thickness for each of the two axial positions recorded. Wave velocities were measured by cross-correlating the amplitude signals from the two axial positions. For the film cross-section observations, two high-speed digital video cameras were used in a stereoscopic arrangement. Comparisons with results from different techniques available in literature indicate that the technique developed presents equivalent accuracy in measuring the liquid film properties. Time-resolved images of longitudinal and cross-section views of the film were recorded, which constitute valuable information provided by the technique implemented. (orig.)

  7. Reduction of gas flow nonuniformity in gas turbine engines by means of gas-dynamic methods

    Science.gov (United States)

    Matveev, V.; Baturin, O.; Kolmakova, D.; Popov, G.

    2017-08-01

    Gas flow nonuniformity is one of the main sources of rotor blade vibrations in the gas turbine engines. Usually, the flow circumferential nonuniformity occurs near the annular frames, located in the flow channel of the engine. This leads to the increased dynamic stresses in blades and as a consequence to the blade damage. The goal of the research was to find an acceptable method of reducing the level of gas flow nonuniformity as the source of dynamic stresses in the rotor blades. Two different methods were investigated during this research. Thus, this study gives the ideas about methods of improving the flow structure in gas turbine engine. On the basis of existing conditions (under development or existing engine) it allows the selection of the most suitable method for reducing gas flow nonuniformity.

  8. Oscillating liquid flow ICF Reactor

    International Nuclear Information System (INIS)

    Petzoldt, R.W.

    1990-01-01

    Oscillating liquid flow in a falling molten salt inertial confinement fusion reactor is predicted to rapidly clear driver beam paths of residual liquid droplets. Oscillating flow will also provide adequate neutron and x-ray protection for the reactor structure with a short (2-m) fall distance permitting an 8 Hz repetition rate. A reactor chamber configuration is presented with specific features to clear the entire heavy-ion beam path of splashed molten salt. The structural components, including the structure between beam ports, are shielded. 3 refs., 12 figs

  9. Perspectives on continuum flow models for force-driven nano-channel liquid flows

    Science.gov (United States)

    Beskok, Ali; Ghorbanian, Jafar; Celebi, Alper

    2017-11-01

    A phenomenological continuum model is developed using systematic molecular dynamics (MD) simulations of force-driven liquid argon flows confined in gold nano-channels at a fixed thermodynamic state. Well known density layering near the walls leads to the definition of an effective channel height and a density deficit parameter. While the former defines the slip-plane, the latter parameter relates channel averaged density with the desired thermodynamic state value. Definitions of these new parameters require a single MD simulation performed for a specific liquid-solid pair at the desired thermodynamic state and used for calibration of model parameters. Combined with our observations of constant slip-length and kinematic viscosity, the model accurately predicts the velocity distribution and volumetric and mass flow rates for force-driven liquid flows in different height nano-channels. Model is verified for liquid argon flow at distinct thermodynamic states and using various argon-gold interaction strengths. Further verification is performed for water flow in silica and gold nano-channels, exhibiting slip lengths of 1.2 nm and 15.5 nm, respectively. Excellent agreements between the model and the MD simulations are reported for channel heights as small as 3 nm for various liquid-solid pairs.

  10. Numerical Method based on SIMPLE Algorithm for a Two-Phase Flow with Non-condensable Gas

    International Nuclear Information System (INIS)

    Kim, Jong Tae

    2009-08-01

    In this study, a numerical method based on SIMPLE algorithm for a two-phase flow with non-condensable gas has been developed in order to simulate thermal hydraulics in a containment of a nuclear power plant. As governing equations, it adopts a two-fluid three-field model for the two-phase flows. The three fields include gas, drops, and continuous liquid. The gas field can contains vapor and non-condensable gases such as air and hydrogen. In order to resolve mixing phenomena of gas species, gas transport equations for each species base on the gas mass fractions are solved with gas phase governing equations such as mass, momentum and energy equations. Methods to evaluate the properties of the gas species were implemented in the code. They are constant or polynomial function based a user input and a property library from Chemkin and JANAF table for gas specific heat. Properties for the gas mixture which are dependent on mole fractions of the gas species were evaluated by a mix rule

  11. Gage for gas flow measurement especially in gas-suction pipes

    International Nuclear Information System (INIS)

    Renner, K.; Stegmanns, W.

    1978-01-01

    The gage utilizes the differential pressure given by a differential pressure producer to generate, in a bypass, a partial gas flow measured by means of a direct-reading anemometer of windmill type. The partial gas flow is generated between pressure pick-up openings in the gas-suction pipe in front of a venturi insert and pressure pick-up openings at the bottleneck of the venturi insert. The reading of the anemometer is proportional to the main gas flow and independent of the variables of state and the properties of the gases to be measured. (RW) [de

  12. Simulating nonlinear steady-state traveling waves on the falling liquid film entrained by a gas flow

    Science.gov (United States)

    Tsvelodub, O. Yu; Bocharov, A. A.

    2017-09-01

    The article is devoted to the simulation of nonlinear waves on a liquid film flowing under gravity in the known stress field at the interface. The paper studies nonlinear waves on a liquid film, flowing under the action of gravity in a known stress field at the interface. In the case of small Reynolds numbers the problem is reduced to the consideration of solutions of the nonlinear integral-differential equation for film thickness deviation from the undisturbed level. The periodic and soliton steady-state traveling solutions of this equation have been numerically found. The analysis of branching of new families of steady-state traveling solutions has been performed. In particular, it is shown that this model equation has solutions in the form of solitons-humps.

  13. Identifying Liquid-Gas System Misconceptions and Addressing Them Using a Laboratory Exercise on Pressure-Temperature Diagrams of a Mixed Gas Involving Liquid-Vapor Equilibrium

    Science.gov (United States)

    Yoshikawa, Masahiro; Koga, Nobuyoshi

    2016-01-01

    This study focuses on students' understandings of a liquid-gas system with liquid-vapor equilibrium in a closed system using a pressure-temperature ("P-T") diagram. By administrating three assessment questions concerning the "P-T" diagrams of liquid-gas systems to students at the beginning of undergraduate general chemistry…

  14. Experiments in stratified gas-liquid pipe flow

    NARCIS (Netherlands)

    Birvalski, M.

    2015-01-01

    The growing demand for energy in the future will necessitate the production of natural gas from fields which are located farther offshore, in deep water and in very cold environments. This will confront us with difficulties in ensuring continuous production of the fluids (natural gas, condensate and

  15. Flow patterns in vertical two-phase flow

    International Nuclear Information System (INIS)

    McQuillan, K.W.; Whalley, P.B.

    1985-01-01

    This paper is concerned with the flow patterns which occur in upwards gas-liquid two-phase flow in vertical tubes. The basic flow patterns are described and the use of flow patter maps is discussed. The transition between plug flow and churn flow is modelled under the assumption that flooding of the falling liquid film limits the stability of plug flow. The resulting equation is combined with other flow pattern transition equations to produce theoretical flow pattern maps, which are then tested against experimental flow pattern data. Encouraging agreement is obtained

  16. Gas-Dynamic Methods to Reduce Gas Flow Nonuniformity from the Annular Frames of Gas Turbine Engines

    Science.gov (United States)

    Kolmakova, D.; Popov, G.

    2018-01-01

    Gas flow nonuniformity is one of the main sources of rotor blade vibrations in the gas turbine engines. Usually, the flow circumferential nonuniformity occurs near the annular frames, located in the flow channel of the engine. This leads to the increased dynamic stresses in blades and consequently to the blade damage. The goal of the research was to find an acceptable method of reducing the level of gas flow nonuniformity. Two different methods were investigated during this research. Thus, this study gives the ideas about methods of improving the flow structure in gas turbine engine. Based on existing conditions (under development or existing engine) it allows the selection of the most suitable method for reducing gas flow nonuniformity.

  17. Technological innovations to development remote gas reserves: gas-to-liquids; Inovacoes tecnologicas no desenvolvimento de reservas remotas de gas natural: gas-to-liquids

    Energy Technology Data Exchange (ETDEWEB)

    Maculan, Berenice D. [Agencia Nacional do Petroleo, Gas Natural e Biocombustiveis (ANP), Rio de Janeiro, RJ (Brazil); Falabella, Eduardo [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2004-07-01

    The GTL - gas to liquids technology was born in Germany, after the 20's with the goal to product liquid fuel from coal to supply the bellicose and domestic demand. The grow of the petroleum industry lead the world to the forgiveness of the GTL technology, except in South Africa. In the last two decades the number of news natural gas reserves and the perspectives of the increase demand from natural gas for the next 20 years change this scenario. Nearly 60% of this reserves are calling stranded or remote, meaning reserves which can't produce with conventional technologies (logistics and economics barriers). So, the oil and gas industry restart to analyze the economics and applicability of the GTL technology. The competitively and applicability of this technology were evaluated and compared to the traditional way of natural gas transport, as well as the solidification of the new environmental rules and the creation of niche to this kind of fuel - the cleans ones - seams the cause of this changes in the oil and gas industries. Which began to adjust to all this news rules and conditions, as show in the sum of investments in R and D area. So, is in this new scenario that the reappear of GTL technology is consider has a technological innovation. (author)

  18. Device for purifying exhaust gas

    International Nuclear Information System (INIS)

    Makita, Kiyoshi.

    1973-01-01

    Purpose: To ensure the reliability in collection of krypton even on accident in liquidizing distillation tower. Constitution: Exhaust gas flows through active carbon adsorption tower where short half-life rare gas in exhaust gas is separated by adsorption, then through heat exchanger, then continuous distillation tower where krypton 85 is separated, then through batch distillation tower where krypton 85 is condensed, and then flows into storing cylinder. On accident in liquidizing distillation tower, at the first period exhaust gas flows through series connected active carbon adsorption tower, krypton 85 adsorbed in adsorption tower being transferred to cooling type adsorption tower, at the next period exhaust gas flows through tower, krypton 85 adsorbed in adsorption tower being transferred to tower. (M. K.)

  19. Extending the accredited low flow liquid calibration range

    NARCIS (Netherlands)

    Platenkamp, Tom; Lötters, Joost Conrad

    2017-01-01

    There is an increasing demand for ISO/IEC 17025:2005 accredited liquid flow calibrations in the range of 1 g/h to 30 kg/h. The accredited Low Flow liquid Calibration Setup [1] (LFCS) at Bronkhorst® covers a flow range of 1 to 200 g/h, leaving a traceability gap in the flow range of 0.2 to 30 kg/h.

  20. A study of gas bubbles in liquid mercury in a vertical Hele-Shaw cell

    Energy Technology Data Exchange (ETDEWEB)

    Klaasen, B.; Blanpain, B. [KU Leuven, Research Group for High Temperature Processes and Industrial Ecology, Department of Metallurgy and Materials Engineering, Leuven (Belgium); Verhaeghe, F. [KU Leuven, Research Group for High Temperature Processes and Industrial Ecology, Department of Metallurgy and Materials Engineering, Leuven (Belgium); Umicore Group Research and Development, Olen (Belgium); Fransaer, J. [KU Leuven, Research Group for Materials with Novel Functionality, Department of Metallurgy and Materials Engineering, Leuven (Belgium)

    2014-01-15

    High-quality observations of mesoscopic gas bubbles in liquid metal are vital for a further development of pyrometallurgical gas injection reactors. However, the opacity of metals enforces the use of indirect imaging techniques with limited temporal or spatial resolution. In addition, accurate interface tracking requires tomography which further complicates the design of a high-temperature experimental setup. In this paper, an alternative approach is suggested that circumvents these two main restrictions. By injecting gas in a thin layer of liquid metal entrapped between two flat and closely spaced plates, bubbles in a Hele-Shaw flow regime are generated. The resulting quasi-2D multiphase flow phenomena can be fully captured from a single point of view and, when using a non-wetted transparent plate material, the bubbles can be observed directly. The feasibility of this approach is demonstrated by observations on buoyancy-driven nitrogen bubbles in liquid mercury in a vertical Hele-Shaw cell. By using a moving high-speed camera to make continuous close up recordings of individual bubbles, the position and geometry of these bubbles are quantified with a high resolution along their entire path. After a thorough evaluation of the experimental accuracy, this information is used for a detailed analysis of the bubble expansion along the path. While the observed bubble growth is mainly caused by the hydrostatic pressure gradient, a careful assessment of the volume variations for smaller bubbles shows that an accurate bubble description should account for significant dynamic pressure variations that seem to be largely regime dependent. (orig.)

  1. The Development of a Gas–Liquid Two-Phase Flow Sensor Applicable to CBM Wellbore Annulus

    Science.gov (United States)

    Wu, Chuan; Wen, Guojun; Han, Lei; Wu, Xiaoming

    2016-01-01

    The measurement of wellbore annulus gas–liquid two-phase flow in CBM (coalbed methane) wells is of great significance for reasonably developing gas drainage and extraction processes, estimating CBM output, judging the operating conditions of CBM wells and analyzing stratum conditions. Hence, a specially designed sensor is urgently needed for real-time measurement of gas–liquid two-phase flow in CBM wellbore annulus. Existing flow sensors fail to meet the requirements of the operating conditions of CBM wellbore annulus due to such factors as an inapplicable measurement principle, larger size, poor sealability, high installation accuracy, and higher requirements for fluid media. Therefore, based on the principle of a target flowmeter, this paper designs a new two-phase flow sensor that can identify and automatically calibrate different flow patterns of two-phase flows. Upon the successful development of the new flow sensor, lab and field tests were carried out, and the results show that the newly designed sensor, with a measurement accuracy of ±2.5%, can adapt to the operating conditions of CBM wells and is reliable for long-term work. PMID:27869708

  2. Study on the effect of distance between the two nozzle holes on interaction of high pressure combustion-gas jets with liquid

    International Nuclear Information System (INIS)

    Xue, Xiaochun; Yu, Yonggang; Zhang, Qi

    2014-01-01

    Highlights: • We design a five-stage cylindrical stepped-wall chamber to study twin combustion-gas jets. • We observe mixing processes of twin combustion-gases and liquid by high speed photographic system. • We discuss the influence of multiple parameters on expansion shape of the Taylor cavities. • The three-dimensional mathematics model is established to simulate the energy release process. • We obtain distribution characteristics of parameters under different nozzle distances. - Abstract: The combustion-gas generator and cylindrical stepped-wall observation chambers with five stages are designed to study the expansion characteristic of twin combustion-gas jets in liquid working medium under high temperature and high pressure. The expansion processes of Taylor cavities formed by combustion-gas jets and the mixing characteristics of gas–liquid are studied by means of high-speed digital camera system. The effects of the distance between the two nozzle holes, injection pressure and nozzle diameter on jet expansion processes are discussed. The experimental results indicate that, the velocity differences exist on the gas–liquid interface during expansion processes of twin combustion-gas jets, and the effect of Taylor–Helmholtz instability is intense, so interfaces between gas and liquid show turbulent folds and randomness. The strong turbulent mixing of gas and liquid leads to release of combustion-gas energy with the temperature decreasing. Moreover, the mixing effectiveness is obviously enhanced on the corners of each step of the cylindrical stepped-wall structure, forming radial expansion phenomenon. The reasonable matching of multi-parameter can restrain the jet instability and make the combustion-gas energy orderly release. Based on the experiments, the three-dimensional unsteady mathematical model of interaction of twin combustion-gas jets and liquid working medium is established to obtain the density, pressure, velocity and temperature

  3. Modeling of two-phase slug flow

    International Nuclear Information System (INIS)

    Fabre, J.; Line, A.

    1992-01-01

    When gas and liquid flow in a pipe, over a range of flow rates, a flow pattern results in which sequences of long bubbles, almost filling the pipe cross section, are successively followed by liquid slugs that may contain small bubbles. This flow pattern, usually called slug flow, is encountered in numerous practical situations, such as in the production of hydrocarbons in wells and their transportation in pipelines; the production of steam and water in geothermal power plants; the boiling and condensation in liquid-vapor systems of thermal power plants; emergency core cooling of nuclear reactors; heat and mass transfer between gas and liquid in chemical reactors. This paper provides a review of two phase slug flow modeling

  4. Multiphase flow in wells and pipelines

    International Nuclear Information System (INIS)

    Sharma, M.P.; Rohatgi, U.S.

    1992-01-01

    This conference focuses primarily on multi-phase flow modeling and calculation methods for oil and gas although two papers focus more on the fluid mechanics of fluidized beds. Papers include theoretical, numerical modeling, experimental investigation, and state-of-the-art review aspects of multiphase flow. The theme of the symposium being general, the papers reflect generality of gas-liquid, liquid-solid, and gas solid flows. One paper deals with nuclear reactor safety as it relates to fluid flow through the reactor

  5. Dynamic analysis of a liquid droplet and optimization of helical angles for vortex drainage gas recovery

    Directory of Open Access Journals (Sweden)

    Xiaodong Wu

    2016-10-01

    Full Text Available Downhole vortex drainage gas recovery is a new gas production technology. So far, however, the forces and motions of liquid phase in the swirling flow field of wellbores during its field application have not been figured out. In this paper, the forces of liquid droplets in the swirling flow field of wellbores were analyzed on the basis of two-phase fluid dynamics theories. Then, the motion equations of fluid droplets along axial and radical directions were established. Magnitude comparison was performed on several typical acting forces, including Basset force, virtual mass force, Magnus force, Saffman force and Stokes force. Besides, the formula for calculating the optimal helical angle of vortex tools was established according to the principle that the vertical resultant force on fluid droplets should be the maximum. And afterwards, each acting force was comprehensively analyzed in terms of its origin, characteristics and direction based on the established force analysis model. Magnitude comparison indicates that the forces with less effect can be neglected, including virtual mass force, Basset force and convection volume force. Moreover, the vertically upward centrifugal force component occurs on the fluid droplets in swirling flow field instead of those in the conventional flow field of wellbores, which is favorable for the fluid droplets to move upward. The reliability of optimal helical angle calculation formula was verified by means of case analysis. It is demonstrated that with the decrease of well depth, the fluid-carrying capability of gas and the optimal helical angle increase. The research results in this paper have a guiding significance to the optimization design of downhole vortex tools and the field application of downhole vortex drainage gas recovery technology.

  6. Efficient simulation of gas-liquid pipe flows using a generalized population balance equation coupled with the algebraic slip model

    KAUST Repository

    Icardi, Matteo; Ronco, Gianni; Marchisio, Daniele Luca; Labois, Mathieu

    2014-01-01

    The inhomogeneous generalized population balance equation, which is discretized with the direct quadrature method of moment (DQMOM), is solved to predict the bubble size distribution (BSD) in a vertical pipe flow. The proposed model is compared with a more classical approach where bubbles are characterized with a constant mean size. The turbulent two-phase flow field, which is modeled using a Reynolds-Averaged Navier-Stokes equation approach, is assumed to be in local equilibrium, thus the relative gas and liquid (slip) velocities can be calculated with the algebraic slip model, thereby accounting for the drag, lift, and lubrication forces. The complex relationship between the bubble size distribution and the resulting forces is described accurately by the DQMOM. Each quadrature node and weight represents a class of bubbles with characteristic size and number density, which change dynamically in time and space to preserve the first moments of the BSD. The predictions obtained are validated against previously published experimental data, thereby demonstrating the advantages of this approach for large-scale systems as well as suggesting future extensions to long piping systems and more complex geometries. © 2014 Elsevier Inc.

  7. Efficient simulation of gas-liquid pipe flows using a generalized population balance equation coupled with the algebraic slip model

    KAUST Repository

    Icardi, Matteo

    2014-09-01

    The inhomogeneous generalized population balance equation, which is discretized with the direct quadrature method of moment (DQMOM), is solved to predict the bubble size distribution (BSD) in a vertical pipe flow. The proposed model is compared with a more classical approach where bubbles are characterized with a constant mean size. The turbulent two-phase flow field, which is modeled using a Reynolds-Averaged Navier-Stokes equation approach, is assumed to be in local equilibrium, thus the relative gas and liquid (slip) velocities can be calculated with the algebraic slip model, thereby accounting for the drag, lift, and lubrication forces. The complex relationship between the bubble size distribution and the resulting forces is described accurately by the DQMOM. Each quadrature node and weight represents a class of bubbles with characteristic size and number density, which change dynamically in time and space to preserve the first moments of the BSD. The predictions obtained are validated against previously published experimental data, thereby demonstrating the advantages of this approach for large-scale systems as well as suggesting future extensions to long piping systems and more complex geometries. © 2014 Elsevier Inc.

  8. 21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid chromatography system for clinical use is a device intended to separate one or more drugs or compounds from a...

  9. Reduction of the suction pressure of a liquid ring vacuum pump with a supersonic gas ejector

    Directory of Open Access Journals (Sweden)

    Olšiak Róbert

    2018-01-01

    Full Text Available A supersonic gas ejector in conjunction with a liquid ring vacuum pump is used for creating and maintaining vacuum in a chamber for technological purposes. In this paper the authors submit an overview about the problematics of suction pressure reduction with a supersonic gas ejector used as a pre-stage of a liquid ring vacuum pump. This system has also the function of a cavitation protection due to the higher pressure present at the suction throat of the vacuum pump. A part of this paper is devoted to the governing equations used at the definition of the flow through an ejector. The experimental studies are then carried out in or own laboratory for verification purposes.

  10. Flue gas carbon capture using hollow fiber membrane diffuser-separator

    Science.gov (United States)

    Ariono, D.; Chandranegara, A. S.; Widodo, S.; Khoiruddin; Wenten, I. G.

    2018-01-01

    In this work, CO2 removal from flue gas using membrane diffuser-separator was investigated. Hollow fiber polypropylene membrane was used as the diffuser while pure water was used as the absorbent. Separation performance of the membrane diffuser-separator as a function of CO2 concentration (6-28%-vol.) and flow rate (gas: 0.8-1.55 L.min-1 and liquid: 0.2-0.7 L.min-1) was investigated and optimized. It was found that CO2 removal was significantly affected by CO2 concentration in the feed gas. On the other hand, CO2 flux was more influenced by flow rates of liquid and gas rather than concentration. The optimized CO2 removal (64%) and flux (1 x 10-4 mol.m-2.s-1) were obtained at the highest gas flow rate (1.55 L.min-1), the lowest liquid flow rate (0.2 L.min-1), and 6.2%-vol. of CO2 concentration. Outlet gas of the membrane diffuser system tends to carry some water vapor, which is affected by gas and liquid flow rate. Meanwhile, in the steady-state operation of the separator, the gas bubbles generated by the membrane diffuser take a long time to be completely degassed from the liquid phase, thus a portion of gas stream was exiting separator through liquid outlet.

  11. The influence of pH on gas-liquid mass transfer in non-Newtonian fluids

    Directory of Open Access Journals (Sweden)

    Li Shaobai

    2017-01-01

    Full Text Available In this study, the effect of pH on the mass transfer of oxygen bubble swarms in non-Newtonian fluids was experimentally studied. The volumetric liquid side mass transfer coefficient (kLa, liquid side mass transfer coefficient (kL, and specific interfacial area (a were investigated. The pH was regulated by the addition of hydrochloric acid and sodium hydroxide (NaOH. It was found that the kLa increased with the gas flow rate increasing and decreased with the apparent viscosity of the liquid increasing. In the case of pH 7 was attributed to the decomposition of the Xanthan molecular structure by the hydroxyl of NaOH.

  12. Performance of Hollow Fiber Membrane Gas-Liquid Contactors to Absorb CO2 Using Diethanolamine (Dea as a Solvent

    Directory of Open Access Journals (Sweden)

    Sutrasno Kartohardjono

    2010-10-01

    Full Text Available This study uses DEA solution to absorb CO2 from the gas flow through the hollow fiber membrane contactors. This study aims to evaluate the performance of hollow fiber membrane contactors to absorb CO2 gas using DEA solution as solvent through mass transfer and hydrodynamics studies. The use of DEA solution is to reduce the mass transfer resistance in the liquid phase, and on the other side, the large contact area of the membrane surface can cover the disadvantage of membrane contactors; additional mass transfer resistance in the membrane phase. During experiments, CO2 feed flows through the fiber lumens, while the 0.01 M DEA solution flows in the shell side of membrane contactors. Experimental results show that the mass transfer coefficients and fluxes of CO2 increase with an increase in both water and DEA solution flow rates. Increasing the amount of fibers in the contactors will decrease the mass transfer and fluxes at the same DEA solution flow rate. Mass transfer coefficients and CO2 fluxes using DEA solution can achieve 28,000 and 7.6 million times greater than using water as solvent, respectively. Hydrodynamics studies show that the liquid pressure drops in the contactors increase with increasing liquid flow rate and number of fibers in the contactors. The friction between water and the fibers in the contactor was more pronounced at lower velocities, and therefore, the value of the friction factor is also higher at lower velocities.

  13. Dual-mode nonlinear instability analysis of a confined planar liquid sheet sandwiched between two gas streams of unequal velocities and prediction of droplet size and velocity distribution using maximum entropy formulation

    Science.gov (United States)

    Dasgupta, Debayan; Nath, Sujit; Bhanja, Dipankar

    2018-04-01

    Twin fluid atomizers utilize the kinetic energy of high speed gases to disintegrate a liquid sheet into fine uniform droplets. Quite often, the gas streams are injected at unequal velocities to enhance the aerodynamic interaction between the liquid sheet and surrounding atmosphere. In order to improve the mixing characteristics, practical atomizers confine the gas flows within ducts. Though the liquid sheet coming out of an injector is usually annular in shape, it can be considered to be planar as the mean radius of curvature is much larger than the sheet thickness. There are numerous studies on breakup of the planar liquid sheet, but none of them considered the simultaneous effects of confinement and unequal gas velocities on the spray characteristics. The present study performs a nonlinear temporal analysis of instabilities in the planar liquid sheet, produced by two co-flowing gas streams moving with unequal velocities within two solid walls. The results show that the para-sinuous mode dominates the breakup process at all flow conditions over the para-varicose mode of breakup. The sheet pattern is strongly influenced by gas velocities, particularly for the para-varicose mode. Spray characteristics are influenced by both gas velocity and proximity to the confining wall, but the former has a much more pronounced effect on droplet size. An increase in the difference between gas velocities at two interfaces drastically shifts the droplet size distribution toward finer droplets. Moreover, asymmetry in gas phase velocities affects the droplet velocity distribution more, only at low liquid Weber numbers for the input conditions chosen in the present study.

  14. US crude oil, natural gas, and natural gas liquids reserves: 1990 annual report

    International Nuclear Information System (INIS)

    1991-09-01

    The primary focus of this report is to provide an accurate estimate of US proved reserves of crude oil, natural gas, and natural gas liquids. These estimates were considered essential to the development, implementation, and evaluation of natural energy policy and legislation. In the past, the government and the public relied upon industry estimates of proved reserves. These estimates were prepared jointly by the American Petroleum Institute (API) and the American Gas Association (AGA) and published in their annual report, Reserves of Crude Oil, Natural Gas Liquids, and Natural Gas in the United States and Canada. However, API and AGA ceased publication of reserves estimates after their 1979 report. By the mid-1970's, various federal agencies had separately established programs to collect data on, verify, or independently estimate domestic proved reserves of crude oil or natural gas. Each program was narrowly defined to meet the particular needs of the sponsoring agency. In response to recognized need for unified, comprehensive proved reserves estimates, Congress in 1977 required the Department of Energy to prepare such estimates. To meet this requirement, the EIA's reserves program was undertaken to establish a unified, verifiable, comprehensive, and continuing statistical series for proved reserves of crude oil and natural gas. The program was expanded to include proved reserves of natural gas liquids in the 1979 report. 36 refs., 11 figs., 16 tabs

  15. Effect of wall thermal conductivity on the heat transfer process in annular turbulent gas flow for constant wall temperature

    International Nuclear Information System (INIS)

    Groshev, A.I.; Anisimov, V.V.; Kashcheev, V.M.; Khudasko, V.V.; Yur'ev, Yu.S.

    1987-01-01

    The effect of wall material on convective heat transfer of turbulent gas flow in an annular tube with account of longitudinal diffusion both in the wall and in the liquid is studied numerically. The conjugated problem is solved for P r =0.7 (Re=10 4 -10 6 ). Based on numerical calculations it is stated that thermal conductivity of the wall and gas essentially affects the degree of preliminary heating of liquid in the range of a non-heated section

  16. Optimal design issues of a gas-to-liquid process

    Energy Technology Data Exchange (ETDEWEB)

    Rafiee, Ahmad

    2012-07-01

    Interests in Fischer-Tropsch (FT) synthesis is increasing rapidly due to the recent improvements of the technology, clean-burning fuels (low sulphur, low aromatics) derived from the FT process and the realization that the process can be used to monetize stranded natural gas resources. The economy of GTL plants depends very much on the natural gas price and there is a strong incentive to reduce the investment cost and in addition there is a need to improve energy efficiency and carbon efficiency. A model is constructed based on the available information in open literature. This model is used to simulate the GTL process with UNISIM DESIGN process simulator. In the FT reactor with cobalt based catalyst, Co2 is inert and will accumulate in the system. Five placements of Co2 removal unit in the GTL process are evaluated from an economical point of view. For each alternative, the process is optimized with respect to steam to carbon ratio, purge ratio of light ends, amount of tail gas recycled to syngas and FT units, reactor volume, and Co2 recovery. The results show that carbon and energy efficiencies and the annual net cash flow of the process with or without Co2 removal unit are not significantly different and there is not much to gain by removing Co2 from the process. It is optimal to recycle about 97 % of the light ends to the process (mainly to the FT unit) to obtain higher conversion of CO and H2 in the reactor. Different syngas configurations in a gas-to-liquid (GTL) plant are studied including auto-thermal reformer (ATR), combined reformer, and series arrangement of Gas Heated Reformer (GHR) and ATR. The Fischer-Tropsch (FT) reactor is based on cobalt catalyst and the degrees of freedom are; steam to carbon ratio, purge ratio of light ends, amount of tail gas recycled to synthesis gas (syngas) and Fischer-Tropsch (FT) synthesis units, and reactor volume. The production rate of liquid hydrocarbons is maximized for each syngas configuration. Installing a steam

  17. Investigation of H2S and CO2 Removal from Gas Streams Using Hollow Fiber Membrane Gas–liquid Contactors

    Directory of Open Access Journals (Sweden)

    S. M. Mirfendereski

    2017-07-01

    Full Text Available Chemical absorption of H2S and CO2 from CH4 was carried out in a polypropylene porous asymmetric hollow fiber membrane contactor (HFMC. A 0.5 mol L–1 aqueous solution of methyldiethanolamine (MDEA was used as chemical absorbent solution. Effects of gas flow rate, liquid flow rate, H2S concentration and CO2 concentration on the H2S outlet concentrations and CO2 removal percentage were investigated. The results showed that the removal of H2S with aqueous solution of MDEA was very high and indicated almost total removal of H2S. Experimental results also indicated that the membrane contactor was very efficient in the removal of trace H2S at high gas/ liquid flow ratio. The removal of H2S was almost complete with a recovery of more than 96 %. Using feed gas mixtures containing 5000 ppm H2S with CO2 concentrations in the range of 4–12 vol.%, the outlet H2S concentration of less than 1.0 ppm was attained with less than 4.0 vol.% of CO2 permeated and absorbed.

  18. The spray characteristic of gas-liquid coaxial swirl injector by experiment

    OpenAIRE

    Chen Chen; Zhihui Yan; Yang Yang; Hongli Gao; Shunhua Yang; Lei Zhang

    2017-01-01

    Using the laser phase Doppler particle analyzer (PDPA), the spray characteristics of gas-liquid coaxial swirl injector were studied. The Sauter mean diameter (SMD), axial velocity and size data rate were measured under different gas injecting pressure drop and liquid injecting pressure drop. Comparing to a single liquid injection, SMD with gas presence is obviously improved. So the gas presence has a significant effect on the atomization of the swirl injector. What’s more, the atomization eff...

  19. Investigations on high speed MHD liquid flow

    International Nuclear Information System (INIS)

    Yamasaki, Takasuke; Kamiyama, Shin-ichi.

    1982-01-01

    Lately, the pressure drop problem of MHD two-phase flow in a duct has been investigated theoretically and experimentally in conjunction with the problems of liquid metal MHD two-phase flow power-generating cycle or of liquid metal boiling two-phase flow in the blanket of a nuclear fusion reactor. Though many research results have been reported so far for MHD single-phase flow, the hydrodynamic studies on high speed two-phase flow are reported only rarely, specifically the study dealing with the generation of cavitation is not found. In the present investigation, the basic equation was derived, analyzing the high speed MHD liquid flow in a diverging duct as the one-dimensional flow of homogeneous two-phase fluid of small void ratio. Furthermore, the theoretical solution for the effect of magnetic field on cavitation-generating conditions was tried. The pressure distribution in MHD flow in a duct largely varies with load factor, and even if the void ratio is small, the pressure distribution in two-phase flow is considerably different from that in single-phase flow. Even if the MHD two-phase flow in a duct is subsonic flow at the throat, the critical conditions may be achieved sometimes in a diverging duct. It was shown that cavitation is more likely to occur as magnetic field becomes more intense if it is generated downstream of the throat. This explains the experimental results qualitatively. (Wakatsuki, Y.)

  20. Void fraction prediction in two-phase flows independent of the liquid phase density changes

    International Nuclear Information System (INIS)

    Nazemi, E.; Feghhi, S.A.H.; Roshani, G.H.

    2014-01-01

    Gamma-ray densitometry is a frequently used non-invasive method to determine void fraction in two-phase gas liquid pipe flows. Performance of flow meters using gamma-ray attenuation depends strongly on the fluid properties. Variations of the fluid properties such as density in situations where temperature and pressure fluctuate would cause significant errors in determination of the void fraction in two-phase flows. A conventional solution overcoming such an obstacle is periodical recalibration which is a difficult task. This paper presents a method based on dual modality densitometry using Artificial Neural Network (ANN), which offers the advantage of measuring the void fraction independent of the liquid phase changes. An experimental setup was implemented to generate the required input data for training the network. ANNs were trained on the registered counts of the transmission and scattering detectors in different liquid phase densities and void fractions. Void fractions were predicted by ANNs with mean relative error of less than 0.45% in density variations range of 0.735 up to 0.98 gcm −3 . Applying this method would improve the performance of two-phase flow meters and eliminates the necessity of periodical recalibration. - Highlights: • Void fraction was predicted independent of density changes. • Recorded counts of detectors/void fraction were used as inputs/output of ANN. • ANN eliminated necessity of recalibration in changeable density of two-phase flows

  1. A liquid helium saver

    International Nuclear Information System (INIS)

    Avenel, O.; Der Nigohossian, G.; Roubeau, P.

    1976-01-01

    A cryostat equipped with a 'liquid helium saver' is described. A mass flow rate M of helium gas at high pressure is injected in a counter-flow heat exchanger extending from room to liquid helium temperature. After isenthalpic expansion through a calibrated flow impedance this helium gas returns via the low pressure side of the heat exchanger. The helium boil-off of the cryostat represents a mass flow rate m, which provides additional precooling of the incoming helium gas. Two operating regimes appear possible giving nearly the same efficiency: (1) high pressure (20 to 25 atm) and minimum flow (M . L/W approximately = 1.5) which would be used in an open circuit with helium taken from a high pressure cylinder; and (2) low pressure (approximately = 3 atm), high flow (M . L/W > 10) which would be used in a closed circuit with a rubber diaphragm pumping-compressing unit; both provide a minimum theoretical boil-off factor of about 8%. Experimental results are reported. (U.K.)

  2. Characterizations of gas purge valves for liquid alignment and gas removal in a microfluidic chip

    International Nuclear Information System (INIS)

    Chuang, Han-Sheng; Thakur, Raviraj; Wereley, Steven T

    2012-01-01

    Two polydimethylsiloxane (PDMS) gas purge valves for excessive gas removal in general lab-on-a-chip applications are presented in this paper. Both valves are devised based on a three-layer configuration comprising a top layer for liquid channels, a membrane and a bottom layer for gas channels. The pneumatic valves work as a normal gateway for fluids when the membrane is bulged down (open state) by vacuum or pushed up (closed state) by pressure. In the closed state, the air in front of a liquid can be removed through a small notch or a permeable PDMS membrane by compressing the liquid. The purge valve with a small notch across its valve seat, termed surface-tension (ST) valve, can be operated with pressure under 11.5 kPa. The liquid is mainly retained by the surface tension resulting from the hydrophobic channel walls. In contrast, the purge valve with vacuum-filled grooves adjacent to a liquid channel, termed gas-permeation (GP) valve, can be operated at pressure above 5.5 kPa. Based on the principle of gas permeation, the excessive air can be slowly removed through the vent grooves. Detailed evaluations of both valves in a pneumatically driven microfluidic chip were conducted. Specifically, the purge valves enable users to remove gas and passively align liquids at desired locations without using sensing devices or feedback circuits. Finally, a rapid mixing reaction was successfully performed with the GP valves, showing their practicability as incorporated in a microfluidic chip. (paper)

  3. Stabilized ultrathin liquid membranes for gas separations

    International Nuclear Information System (INIS)

    Deetz, D.W.

    1987-01-01

    Although immobilized liquid membranes have the desirable properties of high selectivity and permeability, their practical application to gas phase separations is hindered because of the instability of the liquid phase and the relative thickness of current membranes. The problem of liquid instability, which is due to both liquid volatilization and flooding, can be reduced, or eliminated, by immobilizing the liquid phase in pores small enough to significantly reduce the molar free energy of the solution via the Kelvin effect. The obstacle of membrane thickness can be overcome by selectively immobilizing the liquid phase into the skin of a porous asymmetric membranes

  4. Dual-plane ultrasound flow measurements in liquid metals

    International Nuclear Information System (INIS)

    Büttner, Lars; Nauber, Richard; Burger, Markus; Czarske, Jürgen; Räbiger, Dirk; Franke, Sven; Eckert, Sven

    2013-01-01

    An ultrasound measurement system for dual-plane, two-component flow velocity measurements especially in opaque liquids is presented. Present-day techniques for measuring local flow structures in opaque liquids disclose considerable drawbacks concerning line-wise measurement of single ultrasound probes. For studying time-varying flow patterns, conventional ultrasound techniques are either limited by time-consuming mechanical traversing or by the sequential operation of single probes. The measurement system presented within this paper employs four transducer arrays with a total of 100 single elements which allows for flow mapping without mechanical traversing. A high frame rate of several 10 Hz has been achieved due to an efficient parallelization scheme using time-division multiplexing realized by a microcontroller-based electronic switching matrix. The functionality and capability of the measurement system are demonstrated on a liquid metal flow at room temperature inside a cube driven by a rotating magnetic field (RMF). For the first time, the primary and the secondary flow have been studied in detail and simultaneously using a configuration with two crossed measurement planes. The experimental data confirm predictions made by numeric simulation. After a sudden switching on of the RMF, inertial oscillations of the secondary flow were observed by means of a time-resolved measurement with a frame rate of 3.4 Hz. The experiments demonstrate that the presented measurement system is able to investigate complex and transient flow structures in opaque liquids. Due to its ability to study the temporal evolution of local flow structures, the measurement system could provide considerable progress for fluid dynamics research, in particular for applications in the food industry or liquid metal technologies. (paper)

  5. Dual-plane ultrasound flow measurements in liquid metals

    Science.gov (United States)

    Büttner, Lars; Nauber, Richard; Burger, Markus; Räbiger, Dirk; Franke, Sven; Eckert, Sven; Czarske, Jürgen

    2013-05-01

    An ultrasound measurement system for dual-plane, two-component flow velocity measurements especially in opaque liquids is presented. Present-day techniques for measuring local flow structures in opaque liquids disclose considerable drawbacks concerning line-wise measurement of single ultrasound probes. For studying time-varying flow patterns, conventional ultrasound techniques are either limited by time-consuming mechanical traversing or by the sequential operation of single probes. The measurement system presented within this paper employs four transducer arrays with a total of 100 single elements which allows for flow mapping without mechanical traversing. A high frame rate of several 10 Hz has been achieved due to an efficient parallelization scheme using time-division multiplexing realized by a microcontroller-based electronic switching matrix. The functionality and capability of the measurement system are demonstrated on a liquid metal flow at room temperature inside a cube driven by a rotating magnetic field (RMF). For the first time, the primary and the secondary flow have been studied in detail and simultaneously using a configuration with two crossed measurement planes. The experimental data confirm predictions made by numeric simulation. After a sudden switching on of the RMF, inertial oscillations of the secondary flow were observed by means of a time-resolved measurement with a frame rate of 3.4 Hz. The experiments demonstrate that the presented measurement system is able to investigate complex and transient flow structures in opaque liquids. Due to its ability to study the temporal evolution of local flow structures, the measurement system could provide considerable progress for fluid dynamics research, in particular for applications in the food industry or liquid metal technologies.

  6. Hg⁰ removal from flue gas by ionic liquid/H₂O₂.

    Science.gov (United States)

    Cheng, Guangwen; Bai, Bofeng; Zhang, Qiang; Cai, Ming

    2014-09-15

    1-Alkyl-3-methylimidazolium chloride ionic liquids ([Cnmim] Cl, n=4, 6, 8) were prepared. The ionic liquid was then mixed with hydrogen peroxide (H2O2) to form an absorbent. The Hg(0) removal performance of the absorbent was investigated in a gas/liquid scrubber using simulated flue gas. It was found that the ionic liquid/H2O2 mixture was an excellent absorbent and could be used to remove Hg(0) from flue gas. When the mass ratio of H2O2 to ionic liquid was 0.5, the absorbent showed high Hg(0) removal efficiency (up to 98%). The Hg(0) removal efficiency usually increased with the absorption temperature, while decreased with the increase of alkyl chain length in ionic liquid molecule. The Hg(0) removal mechanism involved with Hg(0) oxidation by H2O2 and Hg(2+) transfer from aqueous phase to ionic liquid phase. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Measurements of liquid-phase turbulence in gas–liquid two-phase flows using particle image velocimetry

    International Nuclear Information System (INIS)

    Zhou, Xinquan; Doup, Benjamin; Sun, Xiaodong

    2013-01-01

    Liquid-phase turbulence measurements were performed in an air–water two-phase flow loop with a circular test section of 50 mm inner diameter using a particle image velocimetry (PIV) system. An optical phase separation method-–planar laser-induced fluorescence (PLIF) technique—which uses fluorescent particles and an optical filtration technique, was employed to separate the signals of the fluorescent seeding particles from those due to bubbles and other noises. An image pre-processing scheme was applied to the raw PIV images to remove the noise residuals that are not removed by the PLIF technique. In addition, four-sensor conductivity probes were adopted to measure the radial distribution of the void fraction. Two benchmark tests were performed: the first was a comparison of the PIV measurement results with those of similar flow conditions using thermal anemometry from previous studies; the second quantitatively compared the superficial liquid velocities calculated from the local liquid velocity and void fraction measurements with the global liquid flow rate measurements. The differences of the superficial liquid velocity obtained from the two measurements were bounded within ±7% for single-phase flows and two-phase bubbly flows with the area-average void fraction up to 18%. Furthermore, a preliminary uncertainty analysis was conducted to investigate the accuracy of the two-phase PIV measurements. The systematic uncertainties due to the circular pipe curvature effects, bubble surface reflection effects and other potential uncertainty sources of the PIV measurements were discussed. The purpose of this work is to facilitate the development of a measurement technique (PIV-PLIF) combined with image pre-processing for the liquid-phase turbulence in gas–liquid two-phase flows of relatively high void fractions. The high-resolution data set can be used to more thoroughly understand two-phase flow behavior, develop liquid-phase turbulence models, and assess high

  8. Inhalational anaesthesia with low fresh gas flow

    Directory of Open Access Journals (Sweden)

    Christian Hönemann

    2013-01-01

    Full Text Available During the inhalation of anaesthesia use of low fresh gas flow (0.35-1 L/min has some important advantages. There are three areas of benefit: pulmonary - anaesthesia with low fresh gas flow improves the dynamics of inhaled anaesthesia gas, increases mucociliary clearance, maintains body temperature and reduces water loss. Economic - reduction of anaesthesia gas consumption resulting in significant savings of > 75% and Ecological - reduction in nitrous oxide consumption, which is an important ozone-depleting and heat-trapping greenhouse gas that is emitted. Nevertheless, anaesthesia with high fresh gas flows of 2-6 L/min is still performed, a technique in which rebreathing is practically negligible. This special article describes the clinical use of conventional plenum vaporizers, connected to the fresh gas supply to easily perform low (1 L/min, minimal (0.5 L/min or metabolic flow anaesthesia (0.35 L/min with conventional Primus Draeger® anaesthesia machines in routine clinical practice.

  9. Two-phase flow through small branches in a horizontal pipe with stratified flow

    International Nuclear Information System (INIS)

    Smoglie, C.

    1984-12-01

    This report presents the description and results of experiments designed to determine the mass flow rate and quality through a small break at the bottom, the top or the side of a main pipe with stratified gas-liquid flow. If the interface level is far below (above) the branch, only single-phase gas (liquid) flow enters the branch. For smaller distances the interface is locally deformed because of the pressure decrease due to the fluid acceleration near the branch inlet (Bernoulli effect) and liquid (gas) can be entrained. This report contains photographs illustrating the flow phenomena as well as a general correlation to determine the beginning of entrainment. Results are presented on the branch mass flow rate and quality as a function of a normalized distance between the interface and the branch inlet. A model was developed which enables to predict the branch quality and mass flux. Results from air-water flow through horizontal branches, were extrapolated for steam water flow at high pressure with critical branch mass flux. (orig./HP) [de

  10. Transient Flow Dynamics in Optical Micro Well Involving Gas Bubbles

    Science.gov (United States)

    Johnson, B.; Chen, C. P.; Jenkins, A.; Spearing, S.; Monaco, L. A.; Steele, A.; Flores, G.

    2006-01-01

    The Lab-On-a-Chip Application Development (LOCAD) team at NASA s Marshall Space Flight Center is utilizing Lab-On-a-Chip to support technology development specifically for Space Exploration. In this paper, we investigate the transient two-phase flow patterns in an optic well configuration with an entrapped bubble through numerical simulation. Specifically, the filling processes of a liquid inside an expanded chamber that has bubbles entrapped. Due to the back flow created by channel expansion, the entrapped bubbles tend to stay stationary at the immediate downstream of the expansion. Due to the huge difference between the gas and liquid densities, mass conservation issues associated with numerical diffusion need to be specially addressed. The results are presented in terms of the movement of the bubble through the optic well. Bubble removal strategies are developed that involve only pressure gradients across the optic well. Results show that for the bubble to be moved through the well, pressure pulsations must be utilized in order to create pressure gradients across the bubble itself.

  11. The Development of a Gas–Liquid Two-Phase Flow Sensor Applicable to CBM Wellbore Annulus

    Directory of Open Access Journals (Sweden)

    Chuan Wu

    2016-11-01

    Full Text Available The measurement of wellbore annulus gas–liquid two-phase flow in CBM (coalbed methane wells is of great significance for reasonably developing gas drainage and extraction processes, estimating CBM output, judging the operating conditions of CBM wells and analyzing stratum conditions. Hence, a specially designed sensor is urgently needed for real-time measurement of gas–liquid two-phase flow in CBM wellbore annulus. Existing flow sensors fail to meet the requirements of the operating conditions of CBM wellbore annulus due to such factors as an inapplicable measurement principle, larger size, poor sealability, high installation accuracy, and higher requirements for fluid media. Therefore, based on the principle of a target flowmeter, this paper designs a new two-phase flow sensor that can identify and automatically calibrate different flow patterns of two-phase flows. Upon the successful development of the new flow sensor, lab and field tests were carried out, and the results show that the newly designed sensor, with a measurement accuracy of ±2.5%, can adapt to the operating conditions of CBM wells and is reliable for long-term work.

  12. Flow regimes in vertical gas-solid contact systems

    Energy Technology Data Exchange (ETDEWEB)

    Yerushalmi, J.; Cankurt, N. T.; Geldart, D.; Liss, B.

    1976-01-01

    The flow characteristics in fluidized beds, i.e., gas-solid systems, was studied to determine the flow regimes, the interaction of gas and solid in the various flow regimes and the dependence of this interaction and of transition between flow regimes on the properties of the gas and solid, on the gas and solid flow rates, and on the containing vessel. Fluidized beds with both coarse and fine particles are considered. Test results using high speed photography to view the operation of a 2-dimensional bed are discussed. (LCL)

  13. Modelling of Dispersed Gas-Liquid Flow using LBGK and LPT Approach

    Science.gov (United States)

    Agarwal, Alankar; Prakash, Akshay; Ravindra, B.

    2017-11-01

    The dynamics of gas bubbles play a significant, if not crucial, role in a large variety of industrial process that involves using reactors. Many of these processes are still not well understood in terms of optimal scale-up strategies.An accurate modeling of bubbles and bubble swarms become important for high fidelity bioreactor simulations. This study is a part of the development of robust bubble fluid interaction modules for simulation of industrial-scale reactors. The work presents the simulation of a single bubble rising in a quiescent water tank using current models presented in the literature for bubble-fluid interaction. In this multiphase benchmark problem, the continuous phase (water) is discretized using the Lattice Bhatnagar-Gross and Krook (LBGK) model of Lattice Boltzmann Method (LBM), while the dispersed gas phase (i.e. air-bubble) modeled with the Lagrangian particle tracking (LPT) approach. The cheap clipped fourth order polynomial function is used to model the interaction between two phases. The model is validated by comparing the simulation results for terminal velocity of a bubble at varying bubble diameter and the influence of bubble motion in liquid velocity with the theoretical and previously available experimental data. This work is supported by the ``Centre for Development of Advanced Computing (C-DAC), Pune'' by providing the advanced computational facility in PARAM Yuva-II.

  14. Synthesis gas production via hybrid steam reforming of natural gas and bio-liquids

    OpenAIRE

    Balegedde Ramachandran, P.

    2013-01-01

    This thesis deals with (catalytic) steam reforming of bio-liquids for the production of synthesis gas. Glycerol, both crude from the biodiesel manufacturing and refined, and pyrolysis oil are tested as bio-based feedstocks. Liquid bio-based feeds could be preferred over inhomogeneous fibrous solid biomass because of their logistic advantages, better mineral balance, and better processability. Especially the ease of pressurization, which is required for large scale synthesis gas production, is...

  15. Study of the instability of a film streaming on a vertical plane plate and submitted to a gas counter-current. Transition towards the co-current upward flow

    International Nuclear Information System (INIS)

    Bachir, Aziz

    1987-01-01

    This research thesis addresses the study of a liquid film flowing on a vertical wall in presence of a counter-current gas flow, and of its transition towards an upward co-current flow due to the increase of gas rate, such transition being herein called flooding. In the first part, the author addresses this flooding phenomenon and reports a bibliographical study of experimental and theoretical works. In the second part, he proposes an original theoretical approach to the modelling of a counter-current flow evolving towards a co-current flow: main methods of study of liquid film stability without gas flow, elaboration of the proposed model, study of the linear stability, numerical resolution, and presentation of an original theoretical criterion defining the limits of counter-current flow. The next part reports the experimental works: visualisations of mechanisms resulting in flooding in a rectangular duct, development of an experimental installation, comparison between theoretical and experimental results [fr

  16. Theoretical study on bubble formation and flow condensation in downflow channel with horizontal gas injection

    Science.gov (United States)

    Zhu, Kang; Li, Yanzhong; Wang, Jiaojiao; Ma, Yuan; Wang, Lei; Xie, Fushou

    2018-05-01

    Bubble formation and condensation in liquid pipes occur widely in industrial systems such as cryogenic propellant feeding system. In this paper, an integrated theoretical model is established to give a comprehensive description of the bubble formation, motion and condensation process. The model is validated by numerical simulations and bubble condensation experiments from references, and good agreements are achieved. The bubble departure diameter at the orifice and the flow condensation length in the liquid channel are predicted by the model, and effects of various influencing parameters on bubble behaviors are analyzed. Prediction results indicate that the orifice diameter, the gas feeding rate, and the liquid velocity are the primary influence factors on the bubble departure diameter. The interfacial heat transfer as well as the bubble departure diameter has a direct impact on the bubble flow condensation length, which increases by 2.5 times over a system pressure range of 0.1 0.4 MPa, and decreases by 85% over a liquid subcooling range of 5 30 K. This work could be beneficial to the prediction of bubble formation and flow condensation processes and the design of cryogenic transfer pipes.

  17. A review of solid-fluid selection options for optical-based measurements in single-phase liquid, two-phase liquid-liquid and multiphase solid-liquid flows

    Science.gov (United States)

    Wright, Stuart F.; Zadrazil, Ivan; Markides, Christos N.

    2017-09-01

    Experimental techniques based on optical measurement principles have experienced significant growth in recent decades. They are able to provide detailed information with high-spatiotemporal resolution on important scalar (e.g., temperature, concentration, and phase) and vector (e.g., velocity) fields in single-phase or multiphase flows, as well as interfacial characteristics in the latter, which has been instrumental to step-changes in our fundamental understanding of these flows, and the development and validation of advanced models with ever-improving predictive accuracy and reliability. Relevant techniques rely upon well-established optical methods such as direct photography, laser-induced fluorescence, laser Doppler velocimetry/phase Doppler anemometry, particle image/tracking velocimetry, and variants thereof. The accuracy of the resulting data depends on numerous factors including, importantly, the refractive indices of the solids and liquids used. The best results are obtained when the observational materials have closely matched refractive indices, including test-section walls, liquid phases, and any suspended particles. This paper reviews solid-liquid and solid-liquid-liquid refractive-index-matched systems employed in different fields, e.g., multiphase flows, turbomachinery, bio-fluid flows, with an emphasis on liquid-liquid systems. The refractive indices of various aqueous and organic phases found in the literature span the range 1.330-1.620 and 1.251-1.637, respectively, allowing the identification of appropriate combinations to match selected transparent or translucent plastics/polymers, glasses, or custom materials in single-phase liquid or multiphase liquid-liquid flow systems. In addition, the refractive indices of fluids can be further tuned with the use of additives, which also allows for the matching of important flow similarity parameters such as density and viscosity.

  18. Liquid ultrasonic flow meters for crude oil measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kalivoda, Raymond J.; Lunde, Per

    2005-07-01

    Liquid ultrasonic flow meters (LUFMs) are gaining popularity for the accurate measurement of petroleum products. In North America the first edition of the API standard ''Measurement of liquid hydrocarbons by ultrasonic flow meters using transit time technology'' was issued in February 2005. It addresses both refined petroleum products and crude oil applications. Its field of application is mainly custody transfer applications but it does provide general guidelines for the installation and operation of LUFM's other applications such as allocation, check meters and leak detection. As with all new technologies performance claims are at times exaggerated or misunderstood and application knowledge is limited. Since ultrasonic meters have no moving parts they appear to have fewer limitations than other liquid flow meters. Liquids ultrasonic flow meters, like turbine meters, are sensitive to fluid properties. It is increasingly more difficult to apply on high viscosity products then on lighter hydrocarbon products. Therefore application data or experience on the measurement of refined or light crude oil may not necessarily be transferred to measuring medium to heavy crude oils. Before better and more quantitative knowledge is available on how LUFMs react on different fluids, the arguments advocating reduced need for in-situ proving and increased dependency on laboratory flow calibration (e.g. using water instead of hydrocarbons) may be questionable. The present paper explores the accurate measurement of crude oil with liquid ultrasonic meters. It defines the unique characteristics of the different API grades of crude oils and how they can affect the accuracy of the liquid ultrasonic measurement. Flow testing results using a new LUFM design are discussed. The paper is intended to provide increased insight into the potentials and limitations of crude oil measurement using ultrasonic flow meters. (author) (tk)

  19. Liquid metal flow measurement by neutron radiography

    International Nuclear Information System (INIS)

    Takenaka, N.; Ono, A.; Matsubayashi, M.; Tsuruno, A.

    1996-01-01

    Visualization of a liquid metal flow and image processing methods to measure the vector field are carried out by real-time neutron radiography. The JRR-3M real-time thermal neutron radiography facility in the Japan Atomic Energy Research Institute was used. Lead-bismuth eutectic was used as a working fluid. Particles made from a gold-cadmium intermetallic compound (AuCd 3 ) were used as the tracer for the visualization. The flow vector field was obtained by image processing methods. It was shown that the liquid metal flow vector field was obtainable by real-time neutron radiography when the attenuation of neutron rays due to the liquid metal was less than l/e and the particle size of the tracer was larger than one image element size digitized for the image processing. (orig.)

  20. Numerical simulation of gas flow through unsaturated fractured rock at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Cooper, C.A.

    1990-01-01

    Numerical analysis is used to identify the physical phenomena associated with barometrically driven gas (air and water vapor) flow through unsaturated fractured rock at Yucca Mountain, Nevada. Results from simple finite difference simulations indicate that for a fractured rock scenario, the maximum velocity of air out of an uncased 10 cm borehole is 0.002 m s -1 . An equivalent porous medium (EPM) model was incorporated into a multiphase, multicomponent simulator to test more complex conceptual models. Results indicate that for a typical June day, a diurnal pressure wave propagates about 160 m into the surrounding Tiva Canyon hydrogeologic unit. Dry air that enters the formation evaporates water around the borehole which reduces capillary pressure. Multiphase countercurrent flow develops in the vicinity of the hole; the gas phase flows into the formation while the liquid phase flows toward the borehole. The effect occurs within 0.5 m of the borehole. The amount of water vapor leaving the formation during 1 day is 900 cm 3 . This is less than 0.1% of the total recharge into the formation, suggesting that the barometric effect may be insignificant in drying the unsaturated zone. However, gas phase velocities out of the borehole (3 m s -1 ), indicating that observed flow rates from wells along the east flank of Yucca Mountain were able to be simulated with a barometric model

  1. Flow transition criteria of a liquid jet into a liquid pool

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Shimpei, E-mail: s1630195@u.tsukuba.ac.jp [Graduate School of Systems and Information Engineering, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Abe, Yutaka [Faculty of Engineering, Information and Systems, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Koyama, Kazuya [Reactor Core and Safety Design Department, Mitsubishi FBR Systems, Inc., 2-34-17 Jingumae, Shibuya, Tokyo 150-0001 (Japan)

    2017-04-15

    Highlights: • Jet breakup and droplet formation in immiscible liquid-liquid systems was studied experimentally. • The observed jet breakup behavior was classified into characteristic regimes. • The droplet size distribution was analyzed using image processing. • The variation of droplet size was compared with available melt-jet experiments. • Extrapolation to the expected SFR conditions implied that most of the hydrodynamic conditions would be the atomization regime. - Abstract: To better understand the fundamental interactions between melt jet and coolant during a core-disruptive accident at a sodium-cooled fast reactor, the jet breakup and droplet formation in immiscible liquid-liquid systems were studied experimentally. Experiments using two different pairs of test fluids were carried out at isothermal conditions. The observed jet breakup behavior was classified into characteristic regimes based on the classical Ohnesorge classification in liquid-gas systems. The variation in breakup length obtained in the present liquid-liquid system was similar to that in a liquid-gas system. The droplet size distribution in each breakup regime was analyzed using image processing and droplet formation via pinch-off, satellite formation, and entrainment was observed. The measured droplet size was compared with those available from melt jet experiments. Based on the observation and analysis results, the breakup regimes were organized on a dimensionless operating diagram, with the derived correlations representing the criteria for regime boundaries of a liquid-liquid system. Finally, the experimental data were extrapolated to the expected conditions of a sodium-cooled fast reactor. From this, it was implied that most of the hydrodynamic conditions during an accident would be close to the atomization regime, in which entrainment is the dominant process for droplet formation.

  2. Modeling of radial gas fraction profiles for bubble flow in vertical pipes

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, D.; Krepper, E.; Prasser, H.-M. [Forschungszentrum Rossendorf e.V., Institute of Safety Research, Dresden (Germany)

    2001-07-01

    The paper presents a method for the prediction of radial gas fraction profiles from a given bubble size distribution. The method is based on the assumption of the equilibrium of the forces acting on a bubble perpendicularly to the flow direction. Assuming a large number of bubble size classes radial distributions are calculated separately for all bubble classes. The sum of these distributions is the radial profile of the gas fraction. The results of the model are compared with experimental data for a number of gas and liquid volume flow rates. The experiments were performed at a vertical test loop (inner diameter 50 mm) in FZ-Rossendorf using a wire mesh sensor. The sensor enables the determination of void distributions in the cross section of the loop. A special evaluation procedure supplies bubble size distributions as well as local distributions of bubbles within a predefined interval of bubble sizes. There is a good agreement between experimental and calculated data. In particular the change from wall peaking to core peaking is well predicted. (authors)

  3. Modeling of radial gas fraction profiles for bubble flow in vertical pipes

    International Nuclear Information System (INIS)

    Lucas, D.; Krepper, E.; Prasser, H.-M.

    2001-01-01

    The paper presents a method for the prediction of radial gas fraction profiles from a given bubble size distribution. The method is based on the assumption of the equilibrium of the forces acting on a bubble perpendicularly to the flow direction. Assuming a large number of bubble size classes radial distributions are calculated separately for all bubble classes. The sum of these distributions is the radial profile of the gas fraction. The results of the model are compared with experimental data for a number of gas and liquid volume flow rates. The experiments were performed at a vertical test loop (inner diameter 50 mm) in FZ-Rossendorf using a wire mesh sensor. The sensor enables the determination of void distributions in the cross section of the loop. A special evaluation procedure supplies bubble size distributions as well as local distributions of bubbles within a predefined interval of bubble sizes. There is a good agreement between experimental and calculated data. In particular the change from wall peaking to core peaking is well predicted. (authors)

  4. Mechanics of liquids and gases

    CERN Document Server

    Loitsyanskii, L G; Jones, W P

    1966-01-01

    Mechanics of Liquids and Gases, Second Edition is a 10-chapter text that covers significant revisions concerning the dynamics of an ideal gas, a viscous liquid and a viscous gas.After an expanded introduction to the fundamental properties and methods of the mechanics of fluids, this edition goes on dealing with the kinetics and general questions of dynamics. The next chapters describe the one-dimensional pipe flow of a gas with friction, the elementary theory of the shock tube; Riemann's theory of the wave propagation of finite intensity, and the theory of plane subsonic and supersonic flows.

  5. Behaviour and design considerations for continuous flow closed-open-closed liquid microchannels.

    Science.gov (United States)

    Melin, Jessica; van der Wijngaart, Wouter; Stemme, Göran

    2005-06-01

    This paper introduces a method of combining open and closed microchannels in a single component in a novel way which couples the benefits of both open and closed microfluidic systems and introduces interesting on-chip microfluidic behaviour. Fluid behaviour in such a component, based on continuous pressure driven flow and surface tension, is discussed in terms of cross sectional flow behaviour, robustness, flow-pressure performance, and its application to microfluidic interfacing. The closed-open-closed microchannel possesses the versatility of upstream and downstream closed microfluidics along with open fluidic direct access. The device has the advantage of eliminating gas bubbles present upstream when these enter the open channel section. The unique behaviour of this device opens the door to applications including direct liquid sample interfacing without the need for additional and bulky sample tubing.

  6. Fuel gas production by microwave plasma in liquid

    International Nuclear Information System (INIS)

    Nomura, Shinfuku; Toyota, Hiromichi; Tawara, Michinaga; Yamashita, Hiroshi; Matsumoto, Kenya

    2006-01-01

    We propose to apply plasma in liquid to replace gas-phase plasma because we expect much higher reaction rates for the chemical deposition of plasma in liquid than for chemical vapor deposition. A reactor for producing microwave plasma in a liquid could produce plasma in hydrocarbon liquids and waste oils. Generated gases consist of up to 81% hydrogen by volume. We confirmed that fuel gases such as methane and ethylene can be produced by microwave plasma in liquid

  7. Two-Phase Quality/Flow Meter

    Science.gov (United States)

    Moerk, J. Steven (Inventor); Youngquist, Robert C. (Inventor); Werlink, Rudy J. (Inventor)

    1999-01-01

    A quality and/or flow meter employs a capacitance probe assembly for measuring the dielectric constant of flow stream, particularly a two-phase flow stream including liquid and gas components.ne dielectric constant of the flow stream varies depending upon the volume ratios of its liquid and gas components, and capacitance measurements can therefore be employed to calculate the quality of the flow, which is defined as the volume ratio of liquid in the flow to the total volume ratio of gas and liquid in the flow. By using two spaced capacitance sensors, and cross-correlating the time varying capacitance values of each, the velocity of the flow stream can also be determined. A microcontroller-based processing circuit is employed to measure the capacitance of the probe sensors.The circuit employs high speed timer and counter circuits to provide a high resolution measurement of the time interval required to charge each capacitor in the probe assembly. In this manner, a high resolution, noise resistant, digital representation of each of capacitance value is obtained without the need for a high resolution A/D converter, or a high frequency oscillator circuit. One embodiment of the probe assembly employs a capacitor with two ground plates which provide symmetry to insure that accurate measurements are made thereby.

  8. Interfacial instability induced by a shock wave in a gas-liquid horizontal stratified system

    International Nuclear Information System (INIS)

    Sutradhar, S.C.; Chang, J.S.; Yoshida, H.

    1987-01-01

    The experiments are performed in a rectangular lucite duct equipped with the facility of generating shock waves. Piezo-type pressure transducers are used to monitor the strength and propagation velocity of the shock wave. As the liquid phase has high sound velocity, a prepulse wave system of flow amplitude travels in this phase at a speed faster than the principal shock wave. The magnitude of the transmitted wave in the liquid phase is estimated using a transmission coefficient for gas-liquid system. From the initial pressure ratio of the shock wave, the amplitude of the prepulse as well as the induced interfacial fluid velocity are calculated. The wave length and height of the ripples during the passage of the shock wave are estimated for a specific strength of shock wave moving through the phases. From the high speed photographs, the wave length of the ripples can be assessed. The interfacial friction factor is calculated using colebrook's equation for high speed flow. At least five distinct phenomena are observed to exist during the propagation of a shock wave. These are - (1) the energy carried by the pre-pulse is utilized in perturbing the interface; (2) shock wave induces a mass velocity at the interface; (3) the wavelength of the ripples at the interface is the product of induced interfacial mass velocity and the time period of the prepulse; (4) a portion of the liquid mass of the perturbed interface is entrained in the gas phase may be due to the hydrodynamic lift in that phase; and finally (5) waves with long wavelength are established at the interface

  9. Churn-annular foam flow: experiments and modelling

    NARCIS (Netherlands)

    Westende, J.M.C. van 't; Shoeibi Omrani, P.; Vercauteren, F.F.; Nennie, E.D.

    2016-01-01

    Foam assisted lift is a deliquification method in the oil and gas industry, which aims to prevent or postpone countercurrent gas-liquid flow in maturing gas wells or to assist in removing downhole accumulated liquids. The creation of foam reduces the density of the liquid that needs to be

  10. Gas liquid sampling for closed canisters in KW Basin - test plan

    International Nuclear Information System (INIS)

    Pitkoff, C.C.

    1995-01-01

    Test procedures for the gas/liquid sampler. Characterization of the Spent Nuclear Fuel, SNF, sealed in canisters at KW-Basin is needed to determine the state of storing SNF wet. Samples of the liquid and the gas in the closed canisters will be taken to gain characterization information. Sampling equipment has been designed to retrieve gas and liquid from the closed canisters in KW basin. This plan is written to outline the test requirements for this developmental sampling equipment

  11. Liquid-intake flow around the tip of butterfly proboscis.

    Science.gov (United States)

    Lee, Sang Joon; Lee, Seung Chul; Kim, Bo Heum

    2014-05-07

    Butterflies drink liquid through a slender proboscis using a large pressure gradient induced by the systaltic operation of a muscular pump inside their head. Although the proboscis is a naturally well-designed coiled micro conduit for liquid uptake and deployment, it has been regarded as a simple straw connected to the muscular pump. There are few studies on the transport of liquid food in the proboscis of a liquid-feeding butterfly. To understand the liquid-feeding mechanism in the proboscis of butterflies, the intake flow around the tip of the proboscis was investigated in detail. In this study, the intake flow was quantitatively visualized using a micro-PIV (particle image velocimetry) velocity field measurement technique. As a result, the liquid-feeding process consists of an intake phase, an ejection phase and a rest phase. When butterflies drink pooled liquid, the liquid is not sucked into the apical tip of the proboscis, but into the dorsal linkage aligned longitudinally along the proboscis. To analyze main characteristics of the intake flow around a butterfly proboscis, a theoretical model was established by assuming that liquid is sucked into a line sink whose suction rate linearly decreases proximally. In addition, the intake flow around the tip of a female mosquito׳s proboscis which has a distinct terminal opening was also visualized and modeled for comparison. The present results would be helpful to understand the liquid-feeding mechanism of a butterfly. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Counter current 'emulsion flow' extractor for continuous liquid-liquid extraction from suspended solutions

    International Nuclear Information System (INIS)

    Yanase, Nobuyuki; Naganawa, Hirochika; Nagano, Tetsushi; Noro, Junji

    2011-01-01

    A single current 'emulsion flow' liquid-liquid extraction apparatus has a head with a number of holes from which micrometer-sized droplets of an aqueous phase spout into an organic phase to mix the two liquid phases. For practical use, however, a fatal problem can occur when particulate components in the aqueous phase plug the holes. In the present study, we have succeeded in solving the problem by applying a counter current-type emulsion flow extractor where micrometer-sized droplets of the organic phase are generated. (author)

  13. Numerical study of wave disturbance in liquid cooling film

    Directory of Open Access Journals (Sweden)

    S.R. Shine

    2013-06-01

    Full Text Available Transient numerical simulations are carried out to investigate the liquid-gas interface characteristics associated with liquid film cooling flows. A two-dimensional axisymmetric multi-phase numerical model using finite volume formulation is developed. The model has been validated against available experimental data for liquid-film cooling flows inside tubes. The model has been used to predict the interface characteristics for a variety of imposed parameters and momentum flux ratios under cold flow conditions wherein both the coolant and mainstream are maintained at the same temperature. Disturbance waves are observed at the liquid-gas interface for coolant flows above a critical value and after a finite distance from the inlet. The distance toward the wave inception point increased with the increase of momentum flux ratio. However, at higher momentum flux ratios, the properties of the disturbance waves did not vary significantly. The parameters related to the liquid-gas interface waves, namely, wave velocity, frequency, amplitude and wave length have been analyzed in detail. Analysis indicates that the liquid entrainment is due to the shearing of the disturbance wave crest.

  14. Gas condensate--raw material for producing liquid paraffin hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Aliyeva, R.B.; Alikishi-Zade, G.Yu.; Kuliyev, A.M.; Leonidov, A.N.; Pereverzev, A.N.

    1980-01-01

    The problem of efficient utilization of gas condensates as raw material for removal of a valuable product, liquid paraffins, is examined. A classification of gas condensates is given which is used as raw material for removing these hydrocarbons: gas condensate with high content of n-alkanes (25-40 mass percent), with average content (18-25 mass percent), with low content (12-18 mass percent), light weight fractions compositions, which do not contain fractions up to 200/sup 0/, and also, content ofless than 12% n-alkanes. Gas condensate I-III groups are 30% of the total reserve of gas condensate. Liquid paraffins hydrocarbons, produced from fractions of diesel fuel, which has been removed from Shatlyk gas condensate under conditions which simulate virtual processes of caramide deparaffinization meet all requirements without additional refining.

  15. Modeling of the fluid dynamics and SO{sub 2} absorption in a gas-liquid reactor

    Energy Technology Data Exchange (ETDEWEB)

    Marocco, L. [Alstom Power Italy, Milan (Italy)

    2010-08-01

    This paper illustrates a computational fluid dynamic (CFD) model of a counter-current Open Spray Tower desulphurisation reactor and its application in the simulation of a full-scale industrial equipment. The raw flue gas flows upward while a suspension of water and limestone is sprayed downward from different heights. Thereby sulfur dioxide is washed out of the gas. The two-phase gas-liquid flow inside the equipment has been simulated with an Euler-Lagrange approach using a commercial CFD code, while a model for the SO{sub 2} absorption has been developed and implemented in the software through dedicated modules. Physical absorption is modeled using dual-film theory and appropriate empirical and semi-empirical correlations. The aqueous phase chemistry accounts for the instantaneous equilibrium reactions of eight dissolved species into a slurry droplet. The model is used to simulate an industrial plant at different operating conditions. The numerical results are in good agreement with the measured values of pressure drop and sulphur removal efficiency.

  16. Flow visualization and relative permeability measurements in rough-walled fractures

    International Nuclear Information System (INIS)

    Persoff, P.; Pruess, K.

    1993-01-01

    Two-phase (gas-liquid) flow experiments were done in a natural rock fracture and transparent replicas of natural fractures. Liquid was injected at constant volume flow rate, and gas was injected at either constant mass flow rate or constant pressure. When gas was injected at constant mass flow rate, the gas inlet pressure, and inlet and outlet capillary pressures, generally did not reach steady state but cycled irregularly. Flow visualization showed that this cycling was due to repeated blocking and unblocking of gas flow paths by liquid. Relative permeabilities calculated from flow rate and pressure data show that the sum of the relative permeabilities of the two phases is much less than 1, indicating that each phase interferes strongly with the flow of the other. Comparison of the relative permeability curves with typical curves for porous media (Corey curves) show that the phase interference is stronger in fractures than in typical porous media

  17. Study on condensation of biomass pyrolysis gas by spray bio-oil droplets

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Kun; Cheng, Wen-Long [University of Science and Technology of China (China)], email: wlcheng@ustc.edu.cn; Chen, Jing [Anhui Electric Power Design Institute (China); Shi, Wen-Jing [Anhui Heli Co., Ltd (China)

    2011-07-01

    This is a study of bio-oil generated by fast pyrolysis; a biomass feedstock is heated to pyrolyze at a rapid rate, the gas pyrolyzed is then condensed rapidly. The interesting result is a potential alternative fuel oil. An analysis was made of the effects of the initial pyrolysis gas temperatures, the initial bio-oil droplets temperatures and diameters, and the flow ratio of the gas and the liquid droplets on the heat and mass transfer between the gas and the liquid droplets. A few criterion equations were achieved with respect to the spray condenser. This paper established the gas-liquid phase equilibrium of an aqueous multi-composition system and the spray condensation model coupling heat and mass transfer. Model calculation and analysis showed that: spray condensation can effectively cool the high-temperature pyrolysis gas quickly; with gas liquid flowing, mass transfer rate reduces; and the relationship of gas and liquid flow ratio can achieve good accuracy.

  18. The Liquid Film Flow with Evaporation: Numerical Modelling

    Directory of Open Access Journals (Sweden)

    Rezanova Ekaterina

    2016-01-01

    Full Text Available The flow of thin liquid layer on an inclined substrate is investigated numerically. The mathematical modelling is based on the Oberbeck-Boussinesq equations and the generalized conditions on the thermocapillary boundary simplified during the parametrical analysis. In the framework of the long-wave approximation the evolution equation which determines the thickness of the liquid layer in the case of moderate Reynolds numbers is derived. The results of numerical modelling of the liquid flow with evaporation at the interface are obtained.

  19. Hydrodynamic characteristics of the two-phase flow field at gas-evolving electrodes: numerical and experimental studies

    Science.gov (United States)

    Liu, Cheng-Lin; Sun, Ze; Lu, Gui-Min; Yu, Jian-Guo

    2018-05-01

    Gas-evolving vertical electrode system is a typical electrochemical industrial reactor. Gas bubbles are released from the surfaces of the anode and affect the electrolyte flow pattern and even the cell performance. In the current work, the hydrodynamics induced by the air bubbles in a cold model was experimentally and numerically investigated. Particle image velocimetry and volumetric three-component velocimetry techniques were applied to experimentally visualize the hydrodynamics characteristics and flow fields in a two-dimensional (2D) plane and a three-dimensional (3D) space, respectively. Measurements were performed at different gas rates. Furthermore, the corresponding mathematical model was developed under identical conditions for the qualitative and quantitative analyses. The experimental measurements were compared with the numerical results based on the mathematical model. The study of the time-averaged flow field, three velocity components, instantaneous velocity and turbulent intensity indicate that the numerical model qualitatively reproduces liquid motion. The 3D model predictions capture the flow behaviour more accurately than the 2D model in this study.

  20. Modeling of annular two-phase flow using a unified CFD approach

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haipeng, E-mail: haipengl@kth.se; Anglart, Henryk, E-mail: henryk@kth.se

    2016-07-15

    Highlights: • Annular two-phase flow has been modeled using a unified CFD approach. • Liquid film was modeled based on a two-dimensional thin film assumption. • Both Eulerian and Lagrangian methods were employed for the gas core flow modeling. - Abstract: A mechanistic model of annular flow with evaporating liquid film has been developed using computational fluid dynamics (CFD). The model is employing a separate solver with two-dimensional conservation equations to predict propagation of a thin boiling liquid film on solid walls. The liquid film model is coupled to a solver of three-dimensional conservation equations describing the gas core, which is assumed to contain a saturated mixture of vapor and liquid droplets. Both the Eulerian–Eulerian and the Eulerian–Lagrangian approach are used to describe the droplet and vapor motion in the gas core. All the major interaction phenomena between the liquid film and the gas core flow have been accounted for, including the liquid film evaporation as well as the droplet deposition and entrainment. The resultant unified framework for annular flow has been applied to the steam-water flow with conditions typical for a Boiling Water Reactor (BWR). The simulation results for the liquid film flow rate show good agreement with the experimental data, with the potential to predict the dryout occurrence based on criteria of critical film thickness or critical film flow rate.

  1. Modeling of annular two-phase flow using a unified CFD approach

    International Nuclear Information System (INIS)

    Li, Haipeng; Anglart, Henryk

    2016-01-01

    Highlights: • Annular two-phase flow has been modeled using a unified CFD approach. • Liquid film was modeled based on a two-dimensional thin film assumption. • Both Eulerian and Lagrangian methods were employed for the gas core flow modeling. - Abstract: A mechanistic model of annular flow with evaporating liquid film has been developed using computational fluid dynamics (CFD). The model is employing a separate solver with two-dimensional conservation equations to predict propagation of a thin boiling liquid film on solid walls. The liquid film model is coupled to a solver of three-dimensional conservation equations describing the gas core, which is assumed to contain a saturated mixture of vapor and liquid droplets. Both the Eulerian–Eulerian and the Eulerian–Lagrangian approach are used to describe the droplet and vapor motion in the gas core. All the major interaction phenomena between the liquid film and the gas core flow have been accounted for, including the liquid film evaporation as well as the droplet deposition and entrainment. The resultant unified framework for annular flow has been applied to the steam-water flow with conditions typical for a Boiling Water Reactor (BWR). The simulation results for the liquid film flow rate show good agreement with the experimental data, with the potential to predict the dryout occurrence based on criteria of critical film thickness or critical film flow rate.

  2. Two-phase flow through small branches in a horizontal pipe with stratified flow

    International Nuclear Information System (INIS)

    Smoglie, C.

    1985-02-01

    In the field of reactor safety the occurrence of a small break in a horizontal primary coolant pipe is of great importance. This report presents the description and results of experiments designed to determine the mass flow rate and quality through a small break at the bottom, the top or the side of a main pipe with stratified gas-liquid flow. If the interface level is far below (above) the branch, only single-phase gas (liquid) flow enters the branch. For smaller distances the interface is locally deformed because of the pressure decrease due to the fluid acceleration near the branch inlet (Bernoulli effect) and liquid (gas) can be entrained. This report contains photographs illustrating the flow phenomena as well as a general correlation to determine the beginning of entrainment. Results are presented on the branch mass flow rate and quality as a function of a normalized distance between the interface and the branch inlet. A model was developed which enables to predict the branch quality and mass flux. Results from air-water flow through horizontal branches, were extrapolated for steam water flow at high pressure with critical branch mass flux. (orig./HS) [de

  3. Plasmachemical oxidation processes in a hybrid gas-liquid electrical discharge reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lukes, Petr; Locke, Bruce R [Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, 2525 Pottsdamer Street, Tallahassee, Florida (United States)

    2005-11-21

    Oxidation processes induced in water by pulsed electrical discharges generated simultaneously in the gas phase in close proximity to the water surface and directly in the liquid were investigated in a hybrid series gas-liquid electrical discharge reactor. The mechanism of phenol degradation was studied through its dependence on the gas phase and liquid phase compositions using pure argon and oxygen atmospheres above the liquid and different initial pH values in the aqueous solution. Phenol degradation was significantly enhanced in the hybrid-series reactor compared with the phenol removal by the single-liquid phase discharge reactor. Under an argon atmosphere the mechanism of phenol degradation was mainly caused by the electrophilic attack of OH{center_dot} radicals produced by the liquid phase discharge directly in water and OH{center_dot} radicals produced by the gas phase discharge at the gas-liquid interface. Under an oxygen atmosphere the formation of gaseous ozone dominated over the formation of OH{center_dot} radicals, and the contribution of the gas phase discharge in this case was determined mainly by the dissolution of gaseous ozone into the water and its subsequent interaction with phenol. At high pH phenol was degraded, in addition to the direct attack by ozone, also through indirect reactions of OH{center_dot} radicals formed via a peroxone process by the decomposition of dissolved ozone by hydrogen peroxide produced by the liquid phase discharge. Such a mechanism was proved by the detection of cis,cis-muconic acid and pH-dependent degradation of phenol, which resulted in significantly higher removal of phenol from alkaline solution observed under oxygen atmosphere than in argon.

  4. Plasmachemical oxidation processes in a hybrid gas-liquid electrical discharge reactor

    International Nuclear Information System (INIS)

    Lukes, Petr; Locke, Bruce R

    2005-01-01

    Oxidation processes induced in water by pulsed electrical discharges generated simultaneously in the gas phase in close proximity to the water surface and directly in the liquid were investigated in a hybrid series gas-liquid electrical discharge reactor. The mechanism of phenol degradation was studied through its dependence on the gas phase and liquid phase compositions using pure argon and oxygen atmospheres above the liquid and different initial pH values in the aqueous solution. Phenol degradation was significantly enhanced in the hybrid-series reactor compared with the phenol removal by the single-liquid phase discharge reactor. Under an argon atmosphere the mechanism of phenol degradation was mainly caused by the electrophilic attack of OH· radicals produced by the liquid phase discharge directly in water and OH· radicals produced by the gas phase discharge at the gas-liquid interface. Under an oxygen atmosphere the formation of gaseous ozone dominated over the formation of OH· radicals, and the contribution of the gas phase discharge in this case was determined mainly by the dissolution of gaseous ozone into the water and its subsequent interaction with phenol. At high pH phenol was degraded, in addition to the direct attack by ozone, also through indirect reactions of OH· radicals formed via a peroxone process by the decomposition of dissolved ozone by hydrogen peroxide produced by the liquid phase discharge. Such a mechanism was proved by the detection of cis,cis-muconic acid and pH-dependent degradation of phenol, which resulted in significantly higher removal of phenol from alkaline solution observed under oxygen atmosphere than in argon

  5. Gas-water two-phase flow characterization with Electrical Resistance Tomography and Multivariate Multiscale Entropy analysis.

    Science.gov (United States)

    Tan, Chao; Zhao, Jia; Dong, Feng

    2015-03-01

    Flow behavior characterization is important to understand gas-liquid two-phase flow mechanics and further establish its description model. An Electrical Resistance Tomography (ERT) provides information regarding flow conditions at different directions where the sensing electrodes implemented. We extracted the multivariate sample entropy (MSampEn) by treating ERT data as a multivariate time series. The dynamic experimental results indicate that the MSampEn is sensitive to complexity change of flow patterns including bubbly flow, stratified flow, plug flow and slug flow. MSampEn can characterize the flow behavior at different direction of two-phase flow, and reveal the transition between flow patterns when flow velocity changes. The proposed method is effective to analyze two-phase flow pattern transition by incorporating information of different scales and different spatial directions. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  6. Quantitative tomographic measurements of opaque multiphase flows

    Energy Technology Data Exchange (ETDEWEB)

    GEORGE,DARIN L.; TORCZYNSKI,JOHN R.; SHOLLENBERGER,KIM ANN; O' HERN,TIMOTHY J.; CECCIO,STEVEN L.

    2000-03-01

    An electrical-impedance tomography (EIT) system has been developed for quantitative measurements of radial phase distribution profiles in two-phase and three-phase vertical column flows. The EIT system is described along with the computer algorithm used for reconstructing phase volume fraction profiles. EIT measurements were validated by comparison with a gamma-densitometry tomography (GDT) system. The EIT system was used to accurately measure average solid volume fractions up to 0.05 in solid-liquid flows, and radial gas volume fraction profiles in gas-liquid flows with gas volume fractions up to 0.15. In both flows, average phase volume fractions and radial volume fraction profiles from GDT and EIT were in good agreement. A minor modification to the formula used to relate conductivity data to phase volume fractions was found to improve agreement between the methods. GDT and EIT were then applied together to simultaneously measure the solid, liquid, and gas radial distributions within several vertical three-phase flows. For average solid volume fractions up to 0.30, the gas distribution for each gas flow rate was approximately independent of the amount of solids in the column. Measurements made with this EIT system demonstrate that EIT may be used successfully for noninvasive, quantitative measurements of dispersed multiphase flows.

  7. Effect of gas quantity on two-phase flow characteristics of a mixed-flow pump

    Directory of Open Access Journals (Sweden)

    Qiang Fu

    2016-04-01

    Full Text Available The inlet gas quantity has a great influence on the performance and inner flow characteristics of a mixed-flow pump. In this article, both numerical and experimental methods are used to carry out this research work. The effects under the steady gas volume fraction state and the transient gas quantity variation process on the mixed-flow pump are investigated and compared in detail. It could be concluded that the head of the mixed-flow pump shows slight decline at the low gas volume fraction state, while it decreases sharply at the high gas volume fraction state and then decreases with the increasing gas quantity. There is an obvious asymmetric blade vapor density on the blade suction side under each cavitation state. The cavities can be weakened obviously by increasing the inlet gas volume fraction within a certain range. It has little influence on the internal unsteady flow of the mixed-flow pump when the gas volume fraction is less than 10%, but the pump starts to operate with a great unsteady characteristic when the inlet gas volume fraction increases to 15%.

  8. SUBTASK 3.12 – GASIFICATION, WARM-GAS CLEANUP, AND LIQUID FUELS PRODUCTION WITH ILLINOIS COAL

    Energy Technology Data Exchange (ETDEWEB)

    Stanislowski, Joshua; Curran, Tyler; Henderson, Ann

    2014-06-30

    The goal of this project was to evaluate the performance of Illinois No. 6 coal blended with biomass in a small-scale entrained-flow gasifier and demonstrate the production of liquid fuels under three scenarios. The first scenario used traditional techniques for cleaning the syngas prior to Fischer–Tropsch (FT) synthesis, including gas sweetening with a physical solvent. In the second scenario, the CO2 was not removed from the gas stream prior to FT synthesis. In the third scenario, only warm-gas cleanup techniques were used, such that the feed gas to the FT unit contained both moisture and CO2. The results of the testing showed that the liquid fuels production from the FT catalyst was significantly hindered by the presence of moisture and CO2 in the syngas. Further testing would be needed to determine if this thermally efficient process is feasible with other FT catalysts. This subtask was funded through the EERC–U.S. Department of Energy (DOE) Joint Program on Research and Development for Fossil Energy-Related Resources Cooperative Agreement No. DE-FC26-08NT43291. Nonfederal funding was provided by the Illinois Clean Coal Institute.

  9. Heat transfer to accelerating gas flows

    International Nuclear Information System (INIS)

    Kennedy, T.D.A.

    1978-01-01

    The development of fuels for gas-cooled reactors has resulted in a number of 'gas loop' experiments in materials-testing research reactors. In these experiments, efforts are made to reproduce the conditions expected in gas-cooled power reactors. Constant surface temperatures are sought over a short (300 mm) fuelled length, and because of entrance effects, an accelerating flow is required to increase the heat transfer down-stream from the entrance. Strong acceleration of a gas stream will laminarise the flow even at Reynolds Numbers up to 50000, far above values normally associated with laminar flow. A method of predicting heat transfer in this situation is presented here. An integral method is used to find the velocity profile; this profile is then used in an explicit finite-difference solution of the energy equation to give a temperature profile and resultant heat-transfer coefficient values. The Kline criterion, which compares viscous and disruptive forces, is used to predict whether the flow will be laminar. Experimental results are compared with predictions, and good agreement is found to exist. (author)

  10. Real-Time, Non-Intrusive Detection of Liquid Nitrogen in Liquid Oxygen at High Pressure and High Flow

    Science.gov (United States)

    Singh, Jagdish P.; Yueh, Fang-Yu; Kalluru, Rajamohan R.; Harrison, Louie

    2012-01-01

    An integrated fiber-optic Raman sensor has been designed for real-time, nonintrusive detection of liquid nitrogen in liquid oxygen (LOX) at high pressures and high flow rates in order to monitor the quality of LOX used during rocket engine ground testing. The integrated sensor employs a high-power (3-W) Melles Griot diode-pumped, solid-state (DPSS), frequency-doubled Nd:YAG 532- nm laser; a modified Raman probe that has built-in Raman signal filter optics; two high-resolution spectrometers; and photomultiplier tubes (PMTs) with selected bandpass filters to collect both N2 and O2 Raman signals. The PMT detection units are interfaced with National Instruments Lab- VIEW for fast data acquisition. Studies of sensor performance with different detection systems (i.e., spectrometer and PMT) were carried out. The concentration ratio of N2 and O2 can be inferred by comparing the intensities of the N2 and O2 Raman signals. The final system was fabricated to measure N2 and O2 gas mixtures as well as mixtures of liquid N2 and LOX

  11. Gas and Oil Flow through Wellbore Flaws

    Science.gov (United States)

    Hatambeigi, M.; Anwar, I.; Reda Taha, M.; Bettin, G.; Chojnicki, K. N.; Stormont, J.

    2017-12-01

    We have measured gas and oil flow through laboratory samples that represent two important potential flow paths in wellbores associated with the Strategic Petroleum Reserve (SPR): cement-steel interfaces (microannuli) and cement fractures. Cement fractures were created by tensile splitting of cement cores. Samples to represent microannuli were created by placing thin steel sheets within split cement cores so flow is channeled along the cement-steel interface. The test sequence included alternating gas and oil flow measurements. The test fluids were nitrogen and silicone oil with properties similar to a typical crude oil stored in the SPR. After correcting for non-linear (inertial) flow when necessary, flows were interpreted as effective permeability and hydraulic aperture using the cubic law. For both samples with cement fractures and those with cement-steel interfaces, initial gas and oil permeabilities were comparable. Once saturated with oil, a displacement pressure had to be overcome to establish gas flow through a sample, and the subsequent gas permeability were reduced by more than 50% compared to its initial value. Keywords: wellbore integrity, leakage, fracture, microannulus, SPR. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of NTESS/Honeywell, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2017-8168 A

  12. Gas-rise velocities during kicks

    Energy Technology Data Exchange (ETDEWEB)

    White, D.B. (Sedco Forex (FR))

    1991-12-01

    This paper reports on experiments to examine gas migration rates in drilling muds that were performed in a 15-m-long, 200-mm-ID inclinable flow loop where air injection simulates gas entry during a kick. These tests were conducted using a xanthum gum (a common polymer used in drilling fluids) solution to simulate drilling muds as the liquid phase and air as the gas phase. This work represents a significant extension of existing correlations for gas/liquid flows in large pipe diameters with non- Newtonian fluids. Bubbles rise faster in drilling muds than in water despite the increased viscosity. This surprising result is caused by the change in the flow regime, with large slug-type bubbles forming at lower void fractions. The gas velocity is independent of void fraction, thus simplifying flow modeling. Results show that a gas influx will rise faster in a well than previously believed. This has major implications for kick simulation, with gas arriving at the surface earlier than would be expected and the gas outflow rate being higher than would have been predicted. A model of the two-phase gas flow in drilling mud, including the results of this work, has been incorporated into the joint Schlumberger Cambridge Research (SCR)/BP Intl. kick model.

  13. Natural gas purification using supported ionic liquid membrane

    NARCIS (Netherlands)

    Althuluth, M.A.M.; Overbeek, J.P.; Wees, H.J.; Zubeir, L.F.; Haije, W.G.; Berrouk, A.S.; Peters, C.J.; Kroon, M.C.

    2015-01-01

    This paper examines the possibility of the application of a supported ionic liquid membrane (SILM) for natural gas purification. The ionic liquid (IL) 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([emim][FAP]) was impregnated successfully in the ¿-alumina layer of a tubular

  14. Plasma-catalytic reforming of liquid hydrocarbons

    International Nuclear Information System (INIS)

    Nedybaliuk, O.A.; Chernyak, V.Ya; Kolgan, V.V.; Iukhymenko, V.V.; Solomenko, O.V.; Fedirchyk, I.I.; Martysh, E.V.; Demchina, V.P.; Klochok, N.V.; Dragnev, S.V.

    2015-01-01

    The series of experiments studying the plasma-catalytic reforming of liquid hydrocarbons was carried out. The dynamic plasma-liquid system based on a low-power rotating gliding arc with solid electrodes was used for the investigation of liquid hydrocarbons reforming process. Conversion was done via partial oxidation. A part of oxidant flow was activated by the discharge. Synthesis-gas composition was analysed by means of mass-spectrometry and gas-chromatography. A standard boiler, which operates on natural gas and LPG, was used for the burning of synthesis-gas

  15. Stirling Engine with Unidirectional Gas Flow

    OpenAIRE

    Blumbergs, Ilmars

    2014-01-01

    In this study, a Stirling engine with unidirectional gas flow configuration of beta type Stirling engine is described and studied from kinematic and thermodynamics points of view. Some aspects of the Stirling engine with unidirectional gas flow engine are compared to classic beta type Stirling engines. The aim of research has been to develop a new type of Stirling engine, using SolidWorks 3D design software and Flow Simulation software. In the development process, special attention has been d...

  16. Unsteady numerical simulation for gas–liquid two-phase flow in self-priming process of centrifugal pump

    International Nuclear Information System (INIS)

    Huang, Si; Su, Xianghui; Guo, Jing; Yue, Le

    2014-01-01

    Highlights: • The transient gas–liquid two-phase flow fields in the self-priming centrifugal pump are simulated. • The self-priming time and performance are estimated. • The air void fraction and two phase distribution are obtained.· The hole on the volute plays a significant role for gas exhausting. • The frequency of the impulsive pressure basically conforms to that of the air exhausted out of the pump. - Abstract: Self-priming pumps start up without pre-irrigation, and then work as common pumps when air in the pump is exhausted. The transient gas–liquid flow at the start-up stage inside a self-priming pump is an interesting process which greatly influences performance of the pump. In this paper, a conventional vertical self-priming centrifugal pump was selected as the object. Using unsteady numerical simulation, the authors investigated the transient gas–liquid two-phase flow in the self-priming centrifugal pump during the self-priming process. The main innovation in the simulation was that a section of the suction pipe filled with air was set as the initial condition, which conformed to the actual self-priming conditions. The gas–liquid two-phase distribution, the pressure and velocity in relation to time were computed and analyzed. Flow rates of both phases with time at the pump inlet and outlet were obtained based on the simulation, which could be used to estimate the self-priming time and other performance parameters. Finally, the numerical method and results for gas–liquid two-phase flow in the self-priming pump was partly validated by the pump performance test

  17. Effect of inlet and outlet flow conditions on natural gas parameters in supersonic separation process.

    Directory of Open Access Journals (Sweden)

    Yan Yang

    Full Text Available A supersonic separator has been introduced to remove water vapour from natural gas. The mechanisms of the upstream and downstream influences are not well understood for various flow conditions from the wellhead and the back pipelines. We used a computational model to investigate the effect of the inlet and outlet flow conditions on the supersonic separation process. We found that the shock wave was sensitive to the inlet or back pressure compared to the inlet temperature. The shock position shifted forward with a higher inlet or back pressure. It indicated that an increasing inlet pressure declined the pressure recovery capacity. Furthermore, the shock wave moved out of the diffuser when the ratio of the back pressure to the inlet one was greater than 0.75, in which the state of the low pressure and temperature was destroyed, resulting in the re-evaporation of the condensed liquids. Natural gas would be the subsonic flows in the whole supersonic separator, if the mass flow rate was less than the design value, and it could not reach the low pressure and temperature for the condensation and separation of the water vapor. These results suggested a guidance mechanism for natural gas supersonic separation in various flow conditions.

  18. Method and device for characterization of two-phase flow in pipes

    International Nuclear Information System (INIS)

    Skarsvaag, K.; Sunde, A.J.

    1993-01-01

    Gamma radiation transmission measurements are made with one-shot-collimation to determine the distribution of voids within a gas-liquid mixture flowing in a pipe. The distribution of voids in selected portions of the pipe, taken together with statistical and logical tests applied thereto, provides information from which are determined: type of flow pattern or flow regime, the profile of a large gas bubble in slug flow, and the gas and the liquid volume flow rates in slug flow. 4 refs

  19. Liquid-phase turbulence measurements in air-water two-phase flows over a wide range of void fractions

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xinquan [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, 201 W. 19th Ave., Columbus, OH 43210 (United States); Sun, Xiaodong, E-mail: sun.200@osu.edu [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, 201 W. 19th Ave., Columbus, OH 43210 (United States); Liu, Yang [Nuclear Engineering Program, Department of Mechanical Engineering, Virginia Tech, 635 Prices Fork Road, Blacksburg, VA 24061 (United States)

    2016-12-15

    This paper focuses on liquid-phase turbulence measurements in air-water two-phase flows over a wide range of void fractions and flow regimes, spanning from bubbly, cap-bubbly, slug, to churn-turbulent flows. The measurements have been conducted in two test facilities, the first one with a circular test section and the second one with a rectangular test section. A particle image velocimetry-planar laser-induced fluorescence (PIV-PLIF) system was used to acquire local liquid-phase turbulence information, including the time-averaged velocity and velocity fluctuations in the streamwise and spanwise directions, and Reynolds stress. An optical phase separation method using fluorescent particles and optical filtration technique was adopted to extract the liquid-phase velocity information. An image pre-processing scheme was imposed on the raw PIV images acquired to remove noise due to the presence of bubble residuals and optically distorted particles in the raw PIV images. Four-sensor conductivity probes and high-speed images were also used to acquire the gas-phase information, which was aimed to understand the flow interfacial structure. The highest area-averaged void fraction covered in the measurements for the circular and rectangular test sections was about 40%.

  20. Liquid-phase turbulence measurements in air-water two-phase flows over a wide range of void fractions

    International Nuclear Information System (INIS)

    Zhou, Xinquan; Sun, Xiaodong; Liu, Yang

    2016-01-01

    This paper focuses on liquid-phase turbulence measurements in air-water two-phase flows over a wide range of void fractions and flow regimes, spanning from bubbly, cap-bubbly, slug, to churn-turbulent flows. The measurements have been conducted in two test facilities, the first one with a circular test section and the second one with a rectangular test section. A particle image velocimetry-planar laser-induced fluorescence (PIV-PLIF) system was used to acquire local liquid-phase turbulence information, including the time-averaged velocity and velocity fluctuations in the streamwise and spanwise directions, and Reynolds stress. An optical phase separation method using fluorescent particles and optical filtration technique was adopted to extract the liquid-phase velocity information. An image pre-processing scheme was imposed on the raw PIV images acquired to remove noise due to the presence of bubble residuals and optically distorted particles in the raw PIV images. Four-sensor conductivity probes and high-speed images were also used to acquire the gas-phase information, which was aimed to understand the flow interfacial structure. The highest area-averaged void fraction covered in the measurements for the circular and rectangular test sections was about 40%.