Gas-Liquid Two-Phase Research Articles

A Sensitive Frequency Band Study for Distributed Acoustical Sensing Monitoring Based on the Coupled Simulation of Gas–Liquid Two-Phase Flow and Acoustic Processes

The sensitivity of gas and water phases to DAS acoustic frequency bands can be used to interpret the production profile of horizontal wells. DAS typically collects acoustic signals in the kilohertz range, presenting a key challenge in identifying the sensitive frequency bands of the gas and water phases in the production well for accurate interpretation. In this study, a gas–water two-phase flow–acoustic coupling model for a horizontal well is developed by integrating a gas–water separation flow model with a pipeline acoustic model. The model simulates the sound pressure level (SPL) and amplitude variations of acoustic waves under different flow patterns, spatial locations, and gas–water ratio schemes. The results demonstrate that within the same flow pattern, an increase in the gas–water ratio significantly elevates acoustic amplitude and SPL peaks within the 5–50 Hz frequency band. Analysis of oil field DAS data reveals that the amplitude response range for stages with a lower gas–water ratio falls within 5–10 Hz, whereas stages with a higher gas–water ratio exhibit an amplitude response range of 10–50 Hz.

On hydromagnetic two-phase gas-liquid flow in ciliary channel: An application of a metachronal rhythm

On hydromagnetic two-phase gas-liquid flow in ciliary channel: An application of a metachronal rhythm

Study on the Impact of Porous Media on Condensate Gas Depletion: A Case Study of Reservoir in Xihu Sag.

During the depletion and pressure reduction process in condensate gas reservoirs, the precipitation of condensate oil transforms the single-phase gas flow into a two-phase gas-liquid flow, significantly reducing the permeability. Currently, microscopic studies of the phase behavior of condensate gas in porous media mainly focus on observing and describing the occurrence of condensate oil, lacking quantitative calculations and direct observations of condensate oil throughout the entire depletion cycle. This paper uses a microvisualization method to simulate the depletion process of condensate gas reservoirs. Condensate gases with oil contents of 175.3 and 505.5 g/cm3 were prepared by mixing methane, ethane, hexane, and decane in specific proportions. Pore structures were extracted from thin sections of real core casts, and microfluidic chips with a minimum pore diameter of 20 μm and an areal porosity of 20.75% were fabricated by using a chemical wet etching method. Subsequently, microfluidic condensate gas depletion experiments were conducted with chip images recorded during the depletion process. Grayscale analysis of the depletion images was performed using ImageJ software to quantitatively calculate condensate oil saturation and recovery rates, analyzing the effects of different condensate oil contents on condensate gas depletion, and comparing the differences between depletion in porous media and in a PVT cell. The conclusions drawn are as follows: the dew points of high and low in the porous media are 3.15% and 1.85% higher than those in the PVT cell, respectively. In the early stages of depletion, condensate oil saturation in porous media is higher than that in the PVT cell, while in the middle to late stages, condensate oil saturation in porous media is lower than that in the PVT cell. The condensate oil recovery rate in porous media is significantly higher than the depletion recovery rate in the PVT cell. Condensate oil tends to precipitate and disperse at blind ends and corners, while it easily forms patches in mainstream large pores.

Development and validation of a 1D gas–liquid model for dissolved Mn(II) removal by oxidation process in a square bubble column

Modeling multiphase reactors requires an in-depth multidisciplinary analysis of various phenomena including the chemical kinetics, oxygen mass transfer, as well as the simulation of flows within these contactors. In this study, a 1D model of two-phase flow for Mn(II) removal from drinking water by aeration process is developed and validated. This model is based on the Eulerian description of two-phase gas–liquid flow with the comparison between a one-medium bubble size and a two-bubble class description to represent the bubble population in the heterogeneous flow regime. All the relevant chemical species are simulated by coupling hydrodynamics, gas–liquid mass transfer, and reaction kinetic. A pseudo-first-order model accounting for homogeneous and heterogeneous kinetics is considered for Mn(II) oxidation. The performance of the developed 1D model is compared and validated with experimental data. The 1D model was able to predict quantitatively Mn oxidation as a function of pH, initial Mn(II) and initial Mn(IV) concentrations.

Gas liquid flow pattern prediction in horizontal and slightly inclined pipes: From mechanistic modelling to machine learning

This paper investigates the prediction of two-phase gas-liquid flow regimes in both horizontal and slightly inclined pipes. For this purpose, the mechanistic model of Taitel et al. (1976) and the machine learning approach have been adopted. First, the mechanistic model was implemented, tested and optimised by introducing factors in the transition equations to determine the configuration that gives the highest prediction accuracy for a specific two-phase system for which experimental data points are available. Second, several machine learning models are trained, tested and additionally validated. This is done by splitting the experimental data set corresponding to the pipe inclination range (−10∘ to 10∘) into training, test and validation sets. The best classifier achieved an accuracy of 95.5% after the test step and up to 98.9% after the validation step. Finally, the Taitel et al. model with the optimal configuration and the best machine learning classifier (XGB classifier) are used to generate the two-dimensional flow regime map.

Investigating of vibration and noise characteristics in two-phase gas-liquid flow through a spiral capillary tube

The vaporization of refrigerant in the liquid-phase in spiral capillary tube induces complex two-phase flow that causes vibrations and noise, which affect the performance and stability of refrigeration systems. Therefore, the flow patterns, vibrations, flow-borne and structure-borne noises in spiral capillary tube are explored, and the effects of coil diameters, pitches and temperatures are analyzed. The results showed that the flow upstream the vaporization point was dominant by liquid-phase, then changed to bubbly flow downstream the vaporization point under various structures, and further changed to mist flow near the outlet, while it changed to gas-phase flow near the outlet under high temperature. The flow-borne noise was mainly affected by the flow turbulence, and the total sound pressure level (TSPL) increased by 17.1 % on average as the temperature increased from 309.6 to 317.6 K, and rose with the increase in pitch. As the coil diameter increased, the TSPL first increased and then decreased. Moreover, the maximum deformation of structure increased by 58.33 % as the diameter increased from 35 to 50 mm, but changed little with various pitches. The changing trends of vibration intensity caused the similar variations of structure-borne noise. The TSPL of structure-borne noise increased by 9.14 % with the diameter increasing from 35 to 50 mm, but it changed little at various pitches. The TSPL of structure-borne noise was much higher than flow-borne noise, which meant that improving the structural vibration can control the noise of refrigerant flow in spiral capillary tube.

Gas–Liquid Two-Phase Stirring Dynamics and Droplet Splashing Characteristics in Top-Blown Process

Gas–Liquid Two-Phase Stirring Dynamics and Droplet Splashing Characteristics in Top-Blown Process

A Flow Rate Estimation Method for Gas–Liquid Two-Phase Flow Based on Transformer Neural Network

A Flow Rate Estimation Method for Gas–Liquid Two-Phase Flow Based on Transformer Neural Network

Progress on Numerical Simulation of Gas-Liquid Two-Phase Flow in Self-Priming Pump

The fundamentals of the design and operation of self-priming pumps, as indispensable equipment in industry, have been the focus of research in the field of fluid mechanics. This paper begins with a comprehensive background on self-priming pumps and gas-liquid two-phase flow, and it outlines recent advances in the field. Self-priming pumps within the gas-liquid two-phase flow state and the spatial and temporal evolution of the transient characteristics of self-priming pumps determine the self-priming pump self-absorption performance. Through mastery of the self-absorption mechanism, high-performance self-absorption pump products can be formed to provide theoretical support for the development of products. In current research, numerical simulation has become an important tool for analyzing and predicting the behavior of gas-liquid two-phase flow in self-priming pumps. This paper reviews existing numerical models of gas-liquid two-phase flow and categorizes them. Reviewing these models not only provides us with a comprehensive understanding of the existing research but also offers possible directions for future research. The complexity of gas–liquid interactions and their impact on pump performance is analyzed. Through these detailed discussions, we are able to identify the challenges in the simulation process and summarize what has been achieved. In order to further improve the accuracy and reliability of simulations, this paper introduces the latest simulation techniques and research methodologies, which provide new perspectives for a deeper understanding of gas-liquid two-phase flow. In addition, this paper investigates a variety of factors which affect the operating efficiency of self-priming pumps, including the design parameters, fluid properties, and operating conditions. Comprehensive consideration of these factors is crucial for optimizing pump performance. Finally, this paper summarizes the current research results and identifies the main findings and deficiencies. Based on this, the need to improve the accuracy of numerical simulations and to study the design parameters in depth to improve pump performance is emphasized.

Physical modeling of two-phase liquid–gas processes occurring in the refining ladle for Fe–Si alloy refining process

The article presents the results of research carried out using a water model of a refining ladle for the Fe–Si ferroalloys treatment. These studies were aimed at improving the efficiency of refining and homogenization of liquid Fe–Si ferroalloy in the refining ladle by using a new method of blowing gas through a system of nozzles installed at the bottom of the ladle. The obtained results allowed to determine the proper location of the plug at the bottom of the refining ladle and the possibility of using combined blowing. The tests were carried out for a refining ladle with a capacity of 3 m3 using a physical model on a linear scale of 1:3. The gas flow rate used in the model corresponded proportionally to the value previously used in industrial practice and amounted to 26.8 l/min. Experiments were performed for both combined blowing applications and through a purging plug at the bottom of the ladle. In the case of combined blowing, the volume of the gas stream was divided into two blowing sources (lance and purging plug). As a result of laboratory tests, one of the variants was selected and tested in industrial conditions. These studies confirmed the improvement in the efficiency of refining treatment of the FeSi alloy in terms of reducing the carbon and aluminum content in the alloy.x

Artificial Intelligence Techniques for the Hydrodynamic Characterization of Two-Phase Liquid–Gas Flows: An Overview and Bibliometric Analysis

Accurately and instantly estimating the hydrodynamic characteristics in two-phase liquid–gas flow is crucial for industries like oil, gas, and other multiphase flow sectors to reduce costs and emissions, boost efficiency, and enhance operational safety. This type of flow involves constant slippage between gas and liquid phases caused by a deformable interface, resulting in changes in gas volumetric fraction and the creation of structures known as flow patterns. Empirical and numerical methods used for prediction often result in significant inaccuracies during scale-up processes. Different methodologies based on artificial intelligence (AI) are currently being applied to predict hydrodynamic characteristics in two-phase liquid–gas flow, which was corroborated with the bibliometric analysis where AI techniques were found to have been applied in flow pattern recognition, volumetric fraction determination for each fluid, and pressure gradient estimation. The results revealed that a total of 178 keywords in 70 articles, 29 of which reached the threshold (machine learning, flow pattern, two-phase flow, artificial intelligence, and neural networks as the high predominance), were published mainly in Flow Measurement and Instrumentation. This journal has the highest number of published articles related to the studied topic, with nine articles. The most relevant author is Efteknari-Zadeh, E, from the Institute of Optics and Quantum Electronics.

Upwind Scheme Using Preconditioned Artificial Dissipation for Unsteady Gas-liquid Two-phase Flow and Its Application to Shock Tube Flow

Upwind Scheme Using Preconditioned Artificial Dissipation for Unsteady Gas-liquid Two-phase Flow and Its Application to Shock Tube Flow

Three-Dimensional Numerical Simulation of Gas–Liquid Two-Phase Flow in the Izena Hole, Middle Okinawa Trough, to Clarify the Generation Process of Seafloor Hydrothermal Deposits

Three-Dimensional Numerical Simulation of Gas–Liquid Two-Phase Flow in the Izena Hole, Middle Okinawa Trough, to Clarify the Generation Process of Seafloor Hydrothermal Deposits

Characterization of Gas-Liquid Two-Phase Slug Flow Using Distributed Acoustic Sensing in Horizontal Pipes.

This article discusses the use of distributed acoustic sensing (DAS) for monitoring gas-liquid two-phase slug flow in horizontal pipes, using standard telecommunication fiber optics connected to a DAS integrator for data acquisition. The experiments were performed in a 14 m long, 5 cm diameter transparent PVC pipe with a fiber cable helically wrapped around the pipe. Using mineral oil and compressed air, the system captured various flow rates and gas-oil ratios. New algorithms were developed to characterize slug flow using DAS data, including slug frequency, translational velocity, and the lengths of slug body, slug unit, and the liquid film region that had never been discussed previously. This study employed a high-speed camera next to the fiber cable sensing section for validation purposes and achieved a good correlation among the measurements under all conditions tested. Compared to traditional multiphase flow sensors, this technology is non-intrusive and offers continuous, real-time measurement across long distances and in harsh environments, such as subsurface or downhole conditions. It is cost-effective, particularly where multiple measurement points are required. Characterizing slug flow in real time is crucial to many industries that suffer slug-flow-related issues. This research demonstrated the DAS's potential to characterize slug flow quantitively. It will offer the industry a more optimal solution for facility design and operation and ensure safer operational practices.

Characterization of Bubble Size of Gas–Liquid Two-Phase Flow Using Ultrasonic Signals

Characterization of Bubble Size of Gas–Liquid Two-Phase Flow Using Ultrasonic Signals

Comprehensive analysis of two-phase liquid-gas flow structures in varied channel geometries and thermal environments

Two-phase liquid-gas flows are very often used in practice. It is a branch of knowledge that has been extensively studied for many years. The extensiveness of the topic results from the fact that two-phase flows differ quite significantly, depending on the geometry, hydraulic diameter orientation of the channel, and possible thermal processes occurring in the flow. These differences affect the formation of various flow structures and thus flow resistance and heat transfer if the flow is non-adiabatic. In addition to the impact on the energy consumption of the machines in which the phenomenon occurs, the flow structures affect the stability of the equipment operation. This article presents a literature review and knowledge analysis of flow structures in both adiabatic and non-adiabatic flows in channels of different dimensions, geometry, and orientation. The authors also present the results of their research in flow structures in the liquefaction process, carried out in minichannels, as well as a summary of knowledge in the field of liquid-gas flow structures.

Numerical Simulation Study of Gas-Liquid Two-Phase Flow in a Pressurized Leaching Stirred Tank

The gas-liquid flow and oxygen content in a pressurized leaching stirred tank significantly influence the chemical reaction rates, while the specific dynamics of gas-liquid flow in the sulfuric acid system remain largely unexplored. In this study, a mathematical model of gas-liquid flow within a stirred tank is developed using the Euler-Euler approach, with the turbulence and drag force models being validated against experimental data. Utilizing this validated and reliable model, this study investigates the impacts of the sulfuric acid concentration, baffles, air inlet velocity, and bubble diameter on the flow field and gas holdup in a two-phase system consisting of a sulfuric acid solution and oxygen. The findings indicate that introducing a specific concentration of sulfuric acid decreases the solution velocity and increases the gas holdup within the tank. However, once the sulfuric acid concentration reaches a certain threshold, further increases have a diminished effect on the gas-liquid phases. The installation of baffles enhances the turbulent kinetic energy and increases the gas holdup while only resulting in a minimal 1.2% increase in power consumption. Additionally, the inlet velocity and bubble diameter have a relatively minor impact on the tank’s flow field. However, increasing the inlet velocity significantly boosts the gas holdup, whereas an increase in the bubble diameter marginally reduces it. Furthermore, introducing a sulfuric acid solution into the tank can enhance the gas holdup when the gas inlet velocity is low. Conversely, when the gas inlet velocity is high, the addition of sulfuric acid results in a decrease in the gas holdup. The conclusions from this study contribute to enhancing the mixing effectiveness and oxygen content within the tank, providing a substantial theoretical basis for optimizing the design and operating conditions of pressurized leaching stirred tanks.

Gas–Liquid Two-Phase Flow Measurement Based on Optical Flow Method with Machine Learning Optimization Model

Gas–Liquid two-phase flows are a common flow in industrial production processes. Since these flows inherently consist of discrete phases, it is challenging to accurately measure the flow parameters. In this context, a novel approach is proposed that combines the pyramidal Lucas-Kanade (L–K) optical flow method with the Split Comparison (SC) model measurement method. In the proposed approach, videos of gas–liquid two-phase flows are captured using a camera, and optical flow data are acquired from the flow videos using the pyramid L–K optical flow detection method. To address the issue of data clutter in optical flow extraction, a dynamic median value screening method is introduced to optimize the corner point for optical flow calculations. Machine learning algorithms are employed for the prediction model, yielding high flow prediction accuracy in experimental tests. Results demonstrate that the gradient boosted regression (GBR) model is the most effective among the five preset models, and the optimized SC model significantly improves measurement accuracy compared to the GBR model, achieving an R2 value of 0.97, RMSE of 0.74 m3/h, MAE of 0.52 m3/h, and MAPE of 8.0%. This method offers a new approach for monitoring flows in industrial production processes such as oil and gas.

An experimental investigation on the fluid–structure coupling in horizontal pipes conveying two-phase intermittent flow

Two-phase flow is typically found in several industrial applications, such as in the production and transportation of oil and gas in the petrochemical industry, in the catalytic cracking and microreactors in the chemical industry, and in nuclear reactor cooling pumps. Measurement of two-phase flow features is usually necessary and has been done in several ways, including pressure probes, resistive sensors, gamma-ray, wire-mesh sensor and many others. However, these are either intrusive or invasive techniques, which might be of challenging application in industrial environments, or rely on a hazardous radioactive source. Vibration-based measurement of two-phase flow in pipes stands out as a non-invasive/non-intrusive approach and, consequently, multiphase-flow induced vibration in pipes has receiving increasing attention in recent years. In this work, the dynamic behaviour of a horizontal tube conveying an intermittent two-phase gas-liquid flow is investigated based on indirect approaches. The phenomenon of fluid–structure coupling is investigated using acceleration and pressure measurement. Moreover, the bubble size distribution is estimated from high-speed camera images and a deep learning model for image segmentation, along with its spectral content and time modulation. Focus is given at frequency bands around the cut-on frequencies of the circumferential wave modes of the pipe. An approach based on the estimation of frequency response function of the pressure and vibration at the liquid slug and elongated bubble is proposed, such that the coherence function can be used as quantitative measure of the coupling. Two experimental conditions with intermittent flow are investigated as representative cases. It is shown that there is a great vibration amplification at the cut-on frequencies of circumferential wave modes in pipes due to the corresponding structural wave and pressure coupling. Consequently, the frequency of passage of bubble can be estimated from the demodulation of vibration response filtered at the cut-on modes. The experimental results pave the way for innovative vibration-based measurement approaches.

An Analytical Relative Permeability Model Considering Flow Path Structural Characteristics for Gas-Liquid Two-Phase Flow in Shale Fracture

Summary Relative permeability models are essential in describing the multiphase fluid flow in reservoir rocks. Literature work has shown that the existing theoretical models of relative permeability cannot perfectly describe the two-phase flow experimental data in fractures because those models are mostly developed for porous media (such as sandstone) or proposed without fully taking the specific characteristics of two-phase flow into consideration. In this paper, we propose a theoretical two-phase flow relative permeability model based on the tortuous flow channels, considering the structural characteristics of two-phase flow in the fractures. This model considers that the gas and liquid flow through different channels of different shapes and sizes at the same time. The formula for two-phase relative permeability was derived from cubic law in fracture and Darcy’s law, with the influence of the slip effect of the gas phase also considered. The results from different models were compared using several series of experimental data. The model proposed in this paper has a better fit than the others for the raw experimental data. This study demonstrates that it is crucial to take the flow paths and distribution of the two phases into consideration to model the two-phase flow in fracture accurately. This work also found that the tortuosity of the gas channel at the irreducible liquid saturation has a negative effect on gas relative permeability but positive to liquid relative permeability. Moreover, the model demonstrates that the decrease in aperture leads to an increase in the gas relative permeability due to gas slippage, while the impact of gas slippage reduces under high pressure.