Phase Superficial Velocity Research Articles

Bubble Plume Behavior and Turbulence Characteristics of Gas–Liquid Phase in Power‐Law Fluids

AbstractThe turbulent characteristics of bubble plumes in power‐law fluids are studied by experiments and numerical simulations. The effects of liquid phase rheological properties and superficial gas velocity on liquid phase velocity, shear stress, turbulent kinetic energy, turbulent scale, and gas holdup of the bubble plume are investigated. The velocity, shear stress, and turbulent kinetic energy of the liquid phase are distributed in a circular pattern during the generation stage, forming stage, and free‐surface interaction stage of the bubble plume. The average shear stress and average turbulence kinetic energy that decomposed turbulent scales in CMC aqueous solution are 31–50 times and 1.4–2 times than that in tap water environment. The gas holdup in the flow field decreases with the increase of concentration of liquid phase and increases with the increase of superficial gas velocity. The flow pattern of the bubble plume is significantly affected by the superficial gas velocity and the rheological properties of the liquid phase that affect the transfer of mass and momentum between phases.

An effective droplet sieving method by a trapezoidal stepped microchannel

An effective droplet sieving method by a trapezoidal stepped microchannel

Investigation of the Static Pressure Drop and Production that Occurs due to Flow Patterns in a Perforated Horizontal Wellbore

This study examined the intricate interaction between flow patterns and production within a perforated horizontal wellbore. The study precisely assessed the behavior of static pressure drop by utilizing an array of flow regimes encompassing bubble, dispersed bubble, transitional bubble/slug, slug, stratified, transitional slug/stratified wave, and stratified wave. Remarkably, an upward trend in static pressure drop was observed with increasing water phase presence, while the converse was true for the air phase. Besides, the air phase superficial velocity exhibited a direct correlation with the magnitude of pressure drop fluctuations. The liquid production demonstrated a peak during bubble and slug flow regimes, followed by a descent during the transition to stratified and stratified wave flow. This decline can be attributed to mixing pressure drops localized during the perforations. Furthermore, an upward trend in average liquid production was observed with increasing mixture superficial velocity, primarily due to the dominant presence of the water phase. Additionally, the percentage of liquid production was positively associated with the water's superficial velocity when the air's superficial velocity was held constant. While the experimental and numerical results were in agreement for slugs and structured flows, there were discrepancies in the behavior of static pressure for bubbles, small bubbles, and structured waves.

Revisiting the mechanism responsible for the stratified-slug transition in two-phase flows

Revisiting the mechanism responsible for the stratified-slug transition in two-phase flows

Experimental study on wax deposition of highly paraffinic oil in intermittent gas-oil flow in pipelines

Experimental study on wax deposition of highly paraffinic oil in intermittent gas-oil flow in pipelines

Effects of flow characteristics on the heat transfer mechanism in Taylor flow

Effects of flow characteristics on the heat transfer mechanism in Taylor flow

An optimize empirical correlations for liquid film thickness and interfacial friction factor in vertical gas-liquid annular flow

An optimize empirical correlations for liquid film thickness and interfacial friction factor in vertical gas-liquid annular flow

Measurement of Liquid–Liquid Flows Using Turbine Flowmeter and Conductance Sensor With Multiheight Electrodes in Vertical Pipes

Liquid–liquid two-phase flows are common industrial processes in chemical, petroleum, and other related fields. It is a great challenge for the flow measurement using the turbine flowmeter (TFM) in low-velocity liquid–liquid flows due to the serious slippage effect between the oil and water phases. The complex physical discrepancies between the two phases make the response of TFM vastly different from that in single-phase flow. This study proposes a system combining TFM and conductance sensors with multiheight electrodes (CSMHEs) to determine liquid–liquid two-phase flows. This study investigates the effects of phase distribution and slippage on the wheel hub drag torque. The model of wheel hub drag torque in different flow patterns is established, and a new variable meter factor model of TFM in liquid–liquid flows is constructed. Experiments in 20-mm simulated well reveal that the TFM can make accurate predictions of total flow rate and enable online measurements of individual phase superficial velocities. The absolute average percentage deviations (AAPDs) of superficial water and oil velocities are 2.01% and 7.24%, respectively.

Characterizing two-phase flow-induced vibration in piping structures with U-bends

• Two-phase flow-induced vibration in U-bends has been experimentally investigated. • Local void fraction and vibration signals were analyzed simultaneously. • The maximum response was found for depend on the flow patterns. • A mathematical model was proposed to predict the impact force on the U-bend. • Void fraction and the slip are the key parameters in modelling the dynamic forces. The current work investigates flow-induced vibrations for air-water two-phase passing through bends. The vibration of a 90° U-bend structure with a radius to diameter ratio of 0.4 was investigated experimentally in the vertical, horizontal and axial directions for various upstream flow patterns including bubbly, slug, wavy and annular-dispersed flows. Measurements of the local void fractions at various locations along the U-bend, the upstream piping and at the location of the vibration measurements were used to evaluate the tube vibration response. Both vibration amplitude and frequency were correlated with the two-phase flow parameters such as the superficial phase velocities, slip ratio and the mass quality. The U-bend was found to vibrate due to the redistribution of the two-phases along the flow channel creating three main geometric orientations including vertical, horizontal, and an inclination of 45 o . The vibration response of the U-bend in these three positions was investigated. The results show that the excitation forces of a two-phase flow in a piping structure are highly dependent on the flow pattern and the two-phase flow conditions upstream of the U-bend. In order to understand the complex interaction between the structure vibration and the redistribution of two-phase flow-in flow channels, a mathematical model was proposed to predict the impact force on the U- bend and verified for the slug flow pattern. The fully developed void fraction and the slip between the phases are found to be the key parameters in modelling the dynamic forces affecting the U-bends. The developed slug flow model (SFM) was found to provide an acceptable prediction of the peak impact force on the U-bend for design purposes.

Measurement of Oil–Gas–Water Flows in Vertical Pipes Using Electromagnetic Flowmeter and Dual-Conductance Sensors

Three-phase flows are significantly complicated in comparison to single-phase flows and gas–liquid two-phase flows. So far, faced with the presence of two nonconductive dispersed phases in oil–gas–water three-phase flows, the measurement characteristics of electromagnetic flowmeter (EMF) in three-phase flows are an unresolved problem. The flowrate of three-phase flows is difficult to measure due to the nonuniformity arising from interactions between dispersed phases. Aiming at the difficult problem of production logging in oil wells of three-phase flows, this article reports an experimental study on measuring three-phase flows via the EMF and the dual-conductance sensors. Among them, the phase holdups of three-phase flow in vertical pipe are extracted through newly designed distributed coaxial double-ring conductance sensor (DRCS) and rotating electric field conductance sensor (REFCS). A three-phase flow loop test in a pipe of 20 mm inner diameter is carried out. The results show that the EMF has the ability to substantively measure the flowrate of water phase under three flow patterns (bubble, slug, and churn flows) when the water cut is above 60%, and the average absolute percentage deviation (AAPD) for prediction of superficial water velocity is 3.55%. The measurement of superficial gas and oil velocities is implemented by solving the drift-flux models of three-phase flow based on the phase holdups and superficial water velocity, and the AAPDs for predictions of superficial gas and oil velocities are 4.33% and 5.95%, respectively. This research provides a new measurement strategy for production logging of oil, gas, and water three-phase flow production profile by combining the EMF with dual-conductance sensors.

A Distributed Conductance Cross-Correlation Method for Measuring Low-Velocity and High Water-Cut Oil-Water Flows

Oil-water two-phase flow widely exists in the oil production and transportation. The flow pattern presents obvious complexity due to non-uniform distribution of water and oil. When the onshore oilfields are on a middle-late stage of oil recovery, the oil production gradually decreases and the water-cut increases. Accurate measurement of oil-water two-phase flow is a significant issue to improve oil production performance and optimize oil reservoir management. Therefore, we propose a distributed four-sector conductance cross-correlation sensor to realize the flow pattern classification and the measurement of flow velocity and water holdup for low-velocity and high water-cut oil-water flows in a 20 mm inner diameter pipe. The geometry dimension is optimized according to the sensitive field distributions of the sensor. In the flow loop test of vertical upward oil-water two-phase flow, the output signals measured from upstream and downstream electrodes are used to figure out three flow patterns combining with a high-speed camera, and the cross-correlation velocity. Then we use the kinematic wave theory to connect the relationship between the cross-correlation flow velocity and the mixture flow velocity considering water- cut and flow patterns. In addition, according to Maxwell equation, we calculate the water holdup. Finally, a drift velocity model based on three flow patterns is constructed to measure the oil phase superficial velocity.

FLOW PATTERN, PRESSURE DROP, AND VOID FRACTUION IN VERTICAL TWO COMPONENT TWO-PHASE PIPE FLOW

Two-phase flow pattern, pressure drop, and void fraction in vertical transparent pipe of x m internal diameter and y m length is investigated experimentally. The rig is designed to achieve the measurements of pressure drop and void fraction for different combinations of phase superficial velocities such that the regimes encountered are bubbly, slug and annular, which required a wide range of water and air superficial velocities.

Review of Factors Affecting the Phase-Redistribution in the Branching T-Junction

Whenever T-junctions are used in chemical processes and petroleum industries for two-phase separation, a maldistribution of phases is observed between outlets of the junction. Currently, the regular T-junctions are utilized in the industry due to which equipment downstream faces high liquid carryovers. Unfortunately, downstream equipment is not capable of handling high liquid carryovers and they trip frequently, consequently. This review manuscript summarizes the effect of different factors that influence phase separation in the T-junction. This article refers to the geometrical parameters, phase superficial velocity flow regimes encounter during the separation process, and different side arm modifications. This article is a contribution to this field as it summarizes and concludes all these factors comprehensively, to give a verdict on ways to improve phase separation. It is also recommended that the effect of side arm modifications or combinations must be explored for further understanding.

Measurement of Three-Dimensional Characteristics of Slug Flow

Gas-liquid slug flow in horizontal pipes occurs frequently in industrial applications and is harmful to the piping systems owing to its intermittent structures. Therefore, it is essential to accurately describe the flow structure and investigate the flow mechanism. A non-intrusive fluorescence imaging method is employed to quantitatively reconstruct the slug bubble in a 15mm ID horizontal pipe in this article. Optical distortion correction method is firstly developed to improve the measurement accuracy of the instantaneous gas holdup, and then the time-average axial bubble velocity is simultaneously measured according to the feature matching of cross-sectional images. Additionally, the influence of phase superficial velocity on the interface stability is investigated through the phase holdup and the circumferential curvature distribution analysis. The typical three-dimensional structures of slug bubble are finally reconstructed through the velocity-based bicubic interpolation and median fusion algorithm. Previous correlations and reference instrumentation are used to evaluate the proposed method. Comparison results show that the method can effectively measure the flow parameters and reconstruct slug bubbles.

Experimental Investigation of the Flow Characteristics in Crude Oil Containing Sand and Gas Flowing Along Vertical Pipelines

An experimental study on the flow behavior of crude oil containing sand and air in a vertical pipe with 50 mm diameter was carried out. The experiments were conducted under the following input superficial phase velocities: oil from 0.1 to 2.23 m/s and gas from 0 to 0.34 m/s. Oil was blended with sand in three different volume concentrations, namely, 0.7, 2, and 3%. Two different types of sand were used to investigate the effect of sand size distribution. A comparison between rheological measurements and pipe flow data showed that the stress–strain relationship obtained by the rheometer could be used to predict the transport characteristics in the vertical pipe flow. It was demonstrated that a small gas injection and sand addition can decrease the total pressure and friction pressure gradients. In the oil flow, the injection of air generally increased the friction factor compared to the single-phase flow, especially at low Reynolds numbers. However, the friction factor decreased by adding a small amount of fine sand. The accuracy of the correlation developed in this study was compared with other three correlations widely used in gas–liquid vertical pipe flow.

Surface hydrophobicity change on adiabatic two-phase flow pattern transitions in horizontal tubes

Abstract The effect of surface hydrophobicity on the air-water two-phase flow pattern transition was experimentally investigated. Experiments and the two-phase flow visualization were carried out in a hydrophobic polymer tube (4.76 mm ID). The tube material is fluorinated ethylene propylene (FEP) with a hydrophobic surface, and the static contact angle of a water droplet on a smooth surface is 97.28°. The channel surface was roughened to increase the hydrophobicity. The increased surface roughness results in a microstructured surface texture that forms a fine air trapped layer below the liquid droplet on the polymer surface. The channel surface was rotary ground by sandpaper number grit 400, 320, 100, and 80 to develop microstructure textured surface. The measured static contact angle of the roughened surface was 110.7°, 113.26°, 121.03°, and, 126.28° in order of increasing surface roughness. The two-phase flow of the channels with different contact angles was visualized by a high-speed camera and the flow pattern maps were constructed. Even under the same phase superficial velocity conditions, differences in the degree of hydrophobicity lead to transitions to entirely different patterns. The two-phase flow pattern map with the change in hydrophobicity is partitioned by the change in the modified Weber number as a factor indicative of the degree of surface hydrophobicity. The modified Weber number is defined as the ratio of flow inertia to adhesion force, and the new pattern map of the two-phase flow is redefined to take into account the wall hydrophobicity change.

Review on gas–liquid–liquid three–phase flow patterns, pressure drop, and liquid holdup in pipelines

• Classification and structure of the three-phase flow patterns. • Three-phase flow regime transition maps. • Pressure drop and liquid holdup during three-phase flow. • Modeling and simulation of three-phase flow characteristics. Gas–liquid–liquid three–phase co-current flow commonly occurs in the oil & gas production pipelines. The dynamics of three-phase flow are more complex than single and two-phase flow. High pressure drop and liquid holdup are common flow assurance problems in the upstream oil and gas production pipelines. These problems increase the energy consumption of the flow system, especially in the process of enhanced oil recovery (EOR). Three-phase flow behavior is highly dependent on the flow patterns. For an economical and energy-efficient production process, the flow pattern with less pressure drop and liquid holdup needs to be identified. In this article, three-phase flow patterns’ classification and structures are critically reviewed and discussed in detail. Flow regime transition with the change in volumetric fractions and superficial velocities of phases are also elaborated. The prediction models for flow regime transition and stability, pressure drop, liquid holdup, and three-phase flow characteristics are presented.

Planar dynamics of inclined curved flexible riser carrying slug liquid–gas flows

Abstract Flexible risers transporting hydrocarbon liquid–gas flows may be subject to internal dynamic fluctuations of multiphase densities, velocities and pressure changes. Previous studies have mostly focused on single-phase flows in oscillating pipes or multiphase flows in static pipes whereas understanding of multiphase flow effects on oscillating pipes with variable curvatures is still lacking. The present study aims to numerically investigate fundamental planar dynamics of a long flexible catenary riser carrying slug liquid–gas flows and to analyse the mechanical effects of slug flow characteristics including the slug unit length, translational velocity and fluctuation frequencies leading to resonances. A two-dimensional continuum model, describing the coupled horizontal and vertical motions of an inclined flexible/extensible curved riser subject to the space–time varying fluid weights, flow centrifugal momenta and Coriolis effects, is presented. Steady slug flows are considered and modelled by accounting for the mass–momentum balances of liquid–gas phases within an idealized slug unit cell comprising the slug liquid (containing small gas bubbles) and elongated gas bubble (interfacing with the liquid film) parts. A nonlinear hydrodynamic film profile is described, depending on the pipe diameter, inclination, liquid–gas phase properties, superficial velocities and empirical correlations. These enable the approximation of phase fractions, local velocities and pressure variations which are employed as the time-varying, distributed parameters leading to the slug flow-induced vibration (SIV) of catenary riser. Several key SIV features are numerically investigated, highlighting the slug flow-induced transient drifts due to the travelling masses, amplified mean displacements due to the combined slug weights and flow momenta, extensibility or tension changes due to a reconfiguration of pipe equilibrium, oscillation amplitudes and resonant frequencies. Single- and multi-modal patterns of riser dynamic profiles are determined, enabling the evaluation of associated bending/axial stresses. Parametric studies reveal the individual effect of the slug unit length and the translational velocity on SIV response regardless of the slug characteristic frequency being a function of these two parameters. This key observation is practically useful for the identification of critical maximum response.

An assessment of gas void fraction prediction models in highly viscous liquid and gas two-phase vertical flows

Abstract Gas void fraction plays a significant role in determination of several multiphase flow parameters. Good insight of its behaviour coupled with accurate prediction is imperative for design of efficient equipment which has the potential to translate to higher production rates in the petroleum industry. Against the background of the prevalence of higher viscous and imminent application of highly viscous liquids in the petroleum industry, air-water and air-low viscous liquid mixtures dominate gas void fraction research in vertical pipes. In this work, gas-liquid ( μ l = 100 − 7000 m P a s ) mixtures are used to investigate the behaviour of gas void fraction in vertical pipes. The influence of superficial phase velocities and liquid viscosity are observed. Further, a combined database consisting of experimental and the reported data of Schmidt et al. (2008) is employed to evaluate the predictions of 100 existing correlations. The results indicate that the Hibiki and Ishii (2003) and Bestion (1990) correlations are the overall best and second-best performing correlations. In the absence good performing correlations for churn and annular flows, two correlations each, based on drift flux and slip ratio, are developed respectively. Predictions from these correlations show good agreement with the database and comparable performance with the overall best correlations.

A direct comparison between membrane adsorber and packed column chromatography performance

The purpose of this work was to compare side by side the performance of packed bed and membrane chromatography adsorption processes for protein purification. The comparison was performed using anion exchange media with the same ligand immobilized on the adsorbing surface, namely the strong Q quaternary ammonium group, R-CH2-N+-(CH3)3, and bovine serum albumin (BSA) as a model protein. In addition, the stationary phase volume was held constant for each geometry (3mL) and runs were executed using the same mobile phase superficial velocity. As expected, the packed bed column showed higher equilibrium binding of BSA at 66.9mg/mL versus 43.04mg/mL for the membrane adsorber. Dynamic binding capacities were also higher in the packed bed; for example, at 97.5cm/h, a capacity of 62.8mg/mL was measured for the packed bed versus 20.7mg/mL for the membrane adsorber. The higher equilibrium and dynamic capacities of the packed bed are likely due to the higher surface area per unit volume of the resin. However, the maximum productivity for the membrane adsorber was 111mg/(mLh), a value that was 3.3 times higher than the one of the packed column. The bed utilization - defined as the ratio of the dynamic binding capacity at 10% breakthrough to the saturation binding capacity - was also higher for the packed column at long residence times and lower at short residence times confirming the better performance of membrane chromatography at high flow rates.