Showing papers on "Slug flow published in 2000"
TL;DR: In this paper, the basic concept of two-group interfacial area transport equations has been demonstrated, and the analysis of bubble interactions between spherical/distorted bubbles and cap/slug bubbles has been carried out.
172 citations
TL;DR: In this paper, the transition characteristics of flow pattern and phase distribution were studied experimentally in upward air-water two-phase flow along a large vertical pipe (inner diameter D: 0.2 m, the ratio of pipe length to diameter L/D: 61.5).
160 citations
TL;DR: In this article, an imidazoline-based corrosion inhibitor is applied in a large diameter flow loop system and the Warburg diffusion parameter, b f =σω −1/2 was used to qualitatively analyze inhibitor films formed on the metal surface.
100 citations
96 citations
Journal Article•
TL;DR: In this article, a prototype feedback control algorithm developed jointly by ABB and BP to remove terrain-induced slug flow in the pipeline has been operating at the site since January 2000, with interesting results.
Abstract: The development of slugs of liquid in multiphase pipelines is a major, and expensive, headache for oil producers. For example, in the Hod-Valhall field operated by BP in the North See, problems caused by a drop in oil production have led to terrain-induced slug flow in the pipeline between the wellhead platform and the production platform. The irregular flow results in poor oil/water separation, limits the production capacity, and causes flaring. A prototype feedback control algorithm developed jointly by ABB and BP to remove terrain-induced slug flow in the pipeline has been operating at the site since January, 2000, with interesting results.
90 citations
TL;DR: In this article, the authors report on recent research into magnetohydrodynamic (MHD) phenomena applicable to fusion technology and show that the maximum enhancement for liquid Lithium occurs for values of the interaction parameter in the N=10-20 range.
84 citations
TL;DR: In this article, the authors investigated multiphase flow in basaltic volcanic conduits using analog experiments and theoretical approaches and demonstrated that the growth of gas slugs due to hydrostatic decompression does not affect their ascent velocity and that excess pressure in the slugs remain negligible.
Abstract: Multiphase flow in basaltic volcanic conduits is investigated using analog experiments and theoretical approaches. Depending on gas supply, large gas bubbles (gas slugs) may rise through basaltic magma in regimes of distinct fluid-dynamical behavior: ascent of single slugs, supplied slugs fed from the gas source during ascent, and periodic slug flow. An annular flow regime commences at the highest gas supply rates. A first set of experiments demonstrates that the growth of gas slugs due to hydrostatic decompression does not affect their ascent velocity and that excess pressure in the slugs remain negligible. The applicability of theoretical formulae describing slug ascent velocity as a function of liquid and conduit properties is evaluated in a second set of experiments. A third set of experiments with continuous gas supply into a cylindrical conduit are scaled to basaltic conditions over Morton, Eotvos, Reynolds, and Froude numbers. Gas flow rate and liquid viscosity are varied over the whole range of flow regimes to observe flow dynamics and to measure gas and liquid eruption rates. Foam generation by slug bursting at the surface and partial slug disruption by wake turbulence can modify the bubble content and size distribution of the magma. At the transition from slug to annular flow, when the liquid bridges between the gas slugs disappear, pressure at the conduit entrance drops by ∼60% from the hydrostatic value to the dynamic-flow resistance of the annular flow, which may trigger further degassing in a stored magma to maintain the annular flow regime until the gas supply is exhausted and the eruption ends abruptly. Magma discharge may also terminate when magma ascent is hindered by wall friction in long volcanic conduits and the annular gas flow erodes all magma from the conduit. Supplied slugs are found to reach much higher rise velocities than unsupplied slugs and to collapse to turbulent annular flow upon bursting at the surface. A fourth set of experiments uses a conduit partially blocked by built-in obstacles providing traps for gas pockets. Once gas pockets are filled, rising gas slugs deform but remain intact as they move around obstacles without coalescence or significant velocity changes. Bursting of bubbles coalescing with trapped gas pockets causes pressure signals at least 3 orders of magnitude more powerful than gas pocket oscillation induced by passing liquid. Our experiments suggest a refined classification of Strombolian and Hawaiian eruptions according to time-dependant behavior into sporadically pulsating lava fountains (driven by stochastic rise of single slugs), periodically pulsating lava fountains (resulting from slug flow), and quasi-steady lava fountains (oscillating at the frequency of annular-flow turbulence).
83 citations
TL;DR: In this paper, a model adapted for horizontal flow that assumes a random distribution of slug lengths at the pipe entrance and calculates the evolution of the slug length distribution along a pipe is presented.
76 citations
TL;DR: In this article, a new empirical equation for estimating liquid slug holdup in horizontal and slightly inclined two-phase flow is developed as a function of mixture velocity, liquid viscosity and inclination angle.
72 citations
68 citations
TL;DR: In this article, the effect of small downward inclinations on the formation of slugs was examined with air and water at atmospheric pressure, in a pipe with a diameter of 0.0763 m, a length of 23 m and inclinations of − 0.2, −0.5, and −0 8°.
TL;DR: In this article, a drift-flux model is applied to determine the gas void fraction near the transition region, which is compared with previous models and experimental data, and the results show the improvement in explanation of experimental results.
TL;DR: In this paper, the authors studied the behavior of the trailing air bubbles in a vertical pipe filled with water and quantitatively using video imaging of the flow and subsequent digital image processing of the recorded sequence of images.
TL;DR: In this article, the effect of bubbling on particle deposition on hollow fibre membranes was studied in a specially designed cross-flow cell in which the fibres were arranged with well-controlled spacing such that slug flow could form between fibres.
TL;DR: In this paper, a theoretical approach for the prediction of flow pattern transitions is proposed to achieve more satisfactory results for capillary tubes/channels for upward vertical two-phase air-water flow through one circular and four different non-circular channels with an equivalent (hydraulic) diameter of dh ≥ 6 mm.
TL;DR: In this paper, the characterization of slug-flow hydrodynamics in two sizes of tubular membrane diameters (6 and 15 mm) to quantify the main mechanical phenomena involved in the limitation of particle fouling during cross-flow filtration of suspensions is presented.
Abstract: This article focuses on the characterization of slug-flow hydrodynamics in two sizes of tubular membrane diameters (6 and 15 mm) to quantify the main mechanical phenomena involved in the limitation of particle fouling during cross-flow filtration of suspensions. By using a conductance probe technique, the flow structure was accurately identified for two geometries, and noticeable differences were observed in terms of void fractions, velocities and lengths of Taylor bubbles, and liquid slugs. This characterization allowed some data to be theoretically estimated (wall shear stress, “falling” film velocity, film thickness) thanks to the application of a phenomenological model initially developed for oil pipes. The results obtained in a 15-mm tube showed that the ultrafiltration flux improvement, experimentally achieved with bentonite and yeast suspensions, was partly due to the increase in the wall shear stress, induced by continuous gas sparging inside the tubular filtration module. Other hydrodynamic phenomena linked to the quasi-periodic succession of Taylor bubbles and liquid slugs were also involved in the control of the particle entrainment: intermittency frequency, reversal of the wall shear stress, instantaneous pressure variations in the long bubble wake with a higher level of turbulence, and an enhanced local mixing.
TL;DR: In this article, the effects of multiphase flow on the corrosion product formed on the surface of 1018 C-steel coupons in oil and gas lines in presence of inhibitor oleic imidazoline were reported.
TL;DR: In this paper, a detailed description of the slug dissipation process in a downhill section and the calculation of the dissipation distance are discussed. But the authors do not discuss the physical meaning of these conditions.
TL;DR: In this paper, a mechanistic model for predicting the flow behavior for upward vertical and inclined two-phase slug flow is proposed based on measured void fraction data, which exhibits better performance than the existing models.
TL;DR: In this paper, a comprehensive treatment of all sources of pressure drop within intermittent gas-liquid flows is presented, and the presence of dispersed bubbles in a slug is accounted for, without recourse to the widely used assumption of homogenous flow.
TL;DR: In this paper, the continuity and momentum equations for fully developed and spatially developing slug flows are established by considering the entire film zone as the control volume, and they are used for the calculations of pressure gradient, slug frequency, liquid holdup in the film flow pattern transition, slug dissipation, and slug tracking.
Abstract: The continuity and momentum equations for fully developed and spatially developing slug flows are established by considering the entire film zone as the control volume. They are used for the calculations of pressure gradient, slug frequency, liquid holdup in the film flow pattern transition, slug dissipation, and slug tracking. Comparison with available experimental results shows that these equations correctly describe the slug dynamics in gas-liquid pipe flow.
TL;DR: In this article, experiments on the magnetohydrodynamic (MHD) heat transfer under fusion relevant conditions have been performed in order to quantify the heat transfer capability of such flows especially of the highly heat loaded first wall of a self-cooled liquid metal blanket.
TL;DR: In this paper, the thermal patterns on a heated wall, as related to the flow regime, were studied by using the heated foil infrared technique, and the level of these fluctuations was discussed together with the data about the average heat transfer.
TL;DR: In this paper, an analytical model that includes steam condensation effect has been derived and a parametric study has been performed to predict the onset of countercurrent flow limiting (CCFL) in nearly horizontal countercurrent two-phase flow for various flow rates of water.
TL;DR: In this paper, the use of finite element techniques and Taguchi method to optimize package design for PQFPs with and without a heat slug assembled is discussed. But, it was found that larger Young's modulus of heat slug material and smaller values of temperature coefficient of expansions of mold compound, die pad, and die attachment would yield the least warpage.
Patent•
21 Jun 2000
TL;DR: In this article, a method for manufacturing products by means of an alcoxylation reaction, characterised in that it at leastconsumingconsists of putting the reagents together in the liquid phase, and subsequently leading the reaction medium in the greater part through one or several slug flow reactors (2-3-4;19), also called tube reactors.
Abstract: Method for manufacturing products by means of an
alcoxylation reaction, characterised in that it at least
consists of putting the reagents together in the liquid
phase, and of subsequently leading the reaction medium in
which the reaction takes place at least for the greater
part through one or several slug flow reactors (2-3-4;19),
also called tube reactors.
TL;DR: In this paper, the velocity of a single bubble in a uniform tube of finite length is computed by means of a boundary integral technique, where the velocity at the entrance to the tube is assumed constant and uniform across the pipe, as is the pressure at the outlet.
Patent•
07 Nov 2000
TL;DR: In this article, a method and system for suppressing and controlling liquid slugs and gas surges in a multiphase fluid flow line make use of a gas liquid separator (9) and a gas valve (16) in the gas outlet of said separators, which valves are adjusted automatically in response to variations of one of more selected control variables, such as QGAS, QLiquid, Q Liquid+Qgas, Lliquid, P, and the control variable is changed automatically from time to time if one or more selected variable reaches a pre-set threshold value.
Abstract: A method and system for suppressing and controlling liquid slugs and gas surges in a multiphase fluid flow line make use of a gas liquid separator (9) and a gas valve (16) in the gas outlet (14) and a liquid valve (15) in the liquid outlet (13) of said separators, which valves (15, 16) are adjusted automatically in response to variations of one of more selected control variables, such as QGAS, QLiquid, QLiquid+Qgas, Lliquid, P, and the control variable is changed automatically from time to time if one or more selected control variables reaches a pre-set threshold value.
TL;DR: In this article, the authors investigated the asymmetric phase distribution across a cross-section through extensive experimentation by using the conductivity probe technique and their probability density function analysis have indicated that this feature is initiated in the bubbly-slug flow regime and persists in the entire range of slug and churn flow patterns.