Comparison of the Performance of Commercial Flow Improvers in Wet Gas Horizontal Pipelines

2004 ◽  
Author(s):  
Cheolho Kang ◽  
Parimal P. More ◽  
William Paul Jepson
Keyword(s):  
Pressure Gradient ◽  
Liquid Film ◽  
Liquid Velocity ◽  
Flow Loop ◽  
Gas Phases ◽  
Wet Gas ◽  
Wide Range ◽  
Superficial Gas Velocity ◽  
Flow Improver ◽  
Commercial Oil

There is a conspicuous absence of flow improver work for wet gas pipeline environments. The tests were carried out in a 44 m long, 10.16 cm diameter, industrial scale multiphase flow loop with a wide range of superficial liquid and gas velocities ranging from 0.03 to 0.1 m/s and 4 to 10 m/s, respectively. Oil with a viscosity of 2 cP and carbon dioxide were used as the liquid and gas phases, respectively. Two commercial oil soluble flow improvers (FI-1 and FI-2) were used for the tests. This paper discusses the comparison of the performance of these flow improvers in wet gas pipelines. FI-1 and FI-2 were able to decrease the pressure gradient in most of the cases. At the same superficial liquid velocity, the pressure gradient reduction increased with an increase in the superficial gas velocity. This was due to the increase in turbulence level at the liquid and gas interface. At superficial liquid and gas velocities of 0.1 and 10 m/s, FI-1 showed a maximum effectiveness of 13% with the reduction of pressure gradient from 86 to 75 Pa/m. Whereas, FI-2 achieved the maximum effectiveness of 25% as the pressure gradient decreased to 65 Pa/m at the same conditions. Flow improver-2 showed a better performance than Flow improver-1 at all conditions. The decrease in the height of the liquid film was accompanied with spread of the liquid film around the pipe circumference with the addition of both the flow improvers. The changes in the height of the liquid film were more significant with FI-2 than FI-1. At certain superficial gas velocities, it was seen that a transition in flow pattern occurred from wavy to smooth stratified flow with the addition of both the flow improves. This was because the flow was much smoother at the gas-liquid interface with flow improvers.

Experimental Investigation of Liquid Entrainment in Gas in Horizontal Pipes

2009 ◽  
Author(s):  
I. Mantilla ◽  
L. Gomez ◽  
R. Mohan ◽  
O. Shoham ◽  
G. Kouba ◽  
...  
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Solution Viscosity ◽  
Gas Velocity ◽  
Flow Loop ◽  
Horizontal Pipes ◽  
Wave Characteristics ◽  
Liquid Entrainment ◽  
Wide Range ◽  
Superficial Gas Velocity

The objective of this project is to investigate experimentally the phenomena of liquid entrainment in gas in horizontal pipes. This report contains the results of an experimental study on wave characterization. Entrainment in annular flow in horizontal pipes has been studied experimentally. It has been found out that wave characteristics and entrainment fraction are strongly interrelated and must be utilized together in any related analysis. Two experimental facilities, 2-inch and 6-inch diameter, have been designed, constructed and utilized for entrainment measurements in stratified and annular horizontal flow. For the 2-inch flow loop, the range of superficial liquids velocities are 0.35 cm/s to 10 cm/s, and from 2 m/s to 80 m/s for the superficial gas velocities. For the 6-inch flow loop, the ranges of the superficial liquid velocities and superficial gas velocities are from 0.35 cm/s to 10 cm/s and from 2 m/s to 20 m/s, respectively. Appropriate instrumentation for entrainment (adjustable liquid film extractor) and liquid film characteristics (conductance probes and multi-channel conductivity meter) measurements have been developed and implemented. The effects of fluid properties on entrainment and wave characteristics have been studied by utilizing air-water-Butanol solution (surface tension effects) and air-water-Glycerin solution (viscosity effects). Simultaneous measurements have been carried out for both wave characteristics and entrainment for a wide range of flow conditions. Closure relationships have been developed based on the data for wave celerity, frequency, amplitude and spacing. The entrainment fraction has been normalized with the maximum entrainment fraction and correlated with the ratio of the superficial gas velocity to the superficial gas velocity at the onset. The wave amplitude (Δhw) normalized by the film thickness (hL) tends to values of Δhw / hL = 0.2 to 0.3 for high gas rates. The wave spacing (Lw) for air-water normalized by the mean film thickness (hL) exhibits a clear linear behavior with gas velocity, almost independent of the liquid velocity.

Effect of Drag-Reducing Agent on Slug Characteristics in Multiphase Flow in Inclined Pipes

1999 ◽  
Vol 121 (2) ◽  
pp. 86-90 ◽  
Author(s):  
C. Kang ◽  
W. P. Jepson ◽  
M. Gopal
Keyword(s):  
Pressure Drop ◽  
Multiphase Flow ◽  
Liquid Film ◽  
Froude Number ◽  
Liquid Velocity ◽  
Translational Velocity ◽  
Gas Velocity ◽  
Superficial Gas Velocity ◽  
Inclined Pipes ◽  
Superficial Liquid Velocity

The effect of drag-reducing agent (DRA) on multiphase flow in upward and downward inclined pipes has been studied. The effect of DRA on pressure drop and slug characteristics such as slug translational velocity, the height of the liquid film, slug frequency, and Froude number have been determined. Experiments were performed in 10-cm i.d., 18-m long plexiglass pipes at inclinations of 2 and 15 deg for 50 percent oil-50 percent water-gas. The DRA effect was examined for concentrations ranging from 0 to 50 ppm. Studies were done for superficial liquid velocities between 0.5 and 3 m/s and superficial gas velocities between 2 and 10 m/s. The results indicate that the DRA was effective in reducing the pressure drop for both upflow and downflow in inclined pipes. Pressure gradient reduction of up to 92 percent for stratified flow with a concentration of 50 ppm DRA was achieved in ±2 deg downward inclined flow. The effectiveness of DRA for slug flow was 67 percent at a superficial liquid velocity of 0.5 m/s and superficial gas velocity of 2 m/s in 15 deg upward inclined pipes. Slug translational velocity does not change with DRA concentrations. The slug frequency decreases from 68 to 54 slugs/min at superficial liquid velocity of 1 m/s and superficial gas velocity of 4 m/s in 15 deg upward inclined pipes as the concentration of 50 ppm was added. The height of the liquid film decreased with the addition of DRA, which leads to an increase in Froude number.

Design and Performance of Slug Damper

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Antonio Reinoso ◽  
Luis E. Gomez ◽  
Shoubo Wang ◽  
Ram S. Mohan ◽  
Ovadia Shoham ◽  
...  
Keyword(s):  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate ◽  
Liquid Velocity ◽  
Flow Behavior ◽  
Mechanistic Model ◽  
Gas Velocity ◽  
Flow Loop ◽  
Two Phase ◽  
Superficial Gas Velocity

This study investigates theoretically and experimentally the slug damper as a novel flow conditioning device, which can be used upstream of compact separation systems. In the experimental part, a 3 in. ID slug damper facility has been installed in an existing 2 in. diameter two-phase flow loop. This flow loop includes an upstream slug generator, a gas-liquid cylindrical cyclone (GLCC©, ©The University of Tulsa, 1994) attached to the slug damper downstream and a set of conductance probes for measuring the propagation of the dissipated slug along the damper. Over 200 experimental runs were conducted with artificially generated inlet slugs of 50 ft length (Ls/d=300) that were dumped into the loop upstream of the slug damper, varying the superficial liquid velocity between 0.5 ft/s and 2.5 ft/s and superficial gas velocity between 10 ft/s and 40 ft/s (in the 2 in. inlet pipe) and utilizing segmented orifice opening heights of 1 in., 1.5 in., 2 in., and 3 in. For each experimental run, the measured data included propagation of the liquid slug front in the damper, differential pressure across the segmented orifice, GLCC liquid level, GLCC outlet liquid flow, and static pressure in the GLCC. The data show that the slug damper/GLCC system is capable of dissipating long slugs, narrowing the range of liquid flow rate from the downstream GLCC. Also, the damper capacity to process large slugs is a strong function of the superficial gas velocity (and mixture velocity). The theoretical part includes the development of a mechanistic model for the prediction of the hydrodynamic flow behavior in the slug damper. The model enables the predictions of the outlet liquid flow rate and the available damping time, and in turn the prediction of the slug damper capacity. Comparison between the model predictions and the acquired data reveals an accuracy of ±30% with respect to the available damping time and outlet liquid flow rate. The developed model can be used for design of slug damper units.

scholarly journals Effects of Liquid Velocity on Pressure Gradient, Slip and Interfacial Friction Factor in Annular Flow in Horizontal Pipe

2018 ◽  
Vol 3 (8) ◽  
pp. 5
Author(s):  
Uche Osokogwu
Keyword(s):  
Pressure Gradient ◽  
Friction Factor ◽  
Annular Flow ◽  
Liquid Velocity ◽  
Interfacial Friction ◽  
Gas Velocity ◽  
Horizontal Pipe ◽  
Mixture Density ◽  
Superficial Gas Velocity ◽  
Superficial Liquid Velocity

Experimental investigations on annular flow behaviour in two-phase (air/water) flow in horizontal pipe were conducted using 2-inch (0.0504m) with a total length of 28.68m closed loop system. The emphasis from the experiments were on pressure gradient, slip and interfacial friction factor in annular flow. For interfacial friction factor, the entrainment, gas quality, the droplets and slip mixture density values were obtained through the experimental results which were substituted to determine it. In all, effects of liquid velocity were felt, as increase in superficial liquid velocity, increases the interfacial friction factor and pressure gradient in annular flow in horizontal pipes. More so, increase in superficial gas velocity, reduces the interfacial friction factor. Thus, interfacial friction factor decreases with increases in superficial gas velocity, while the pressure gradient increases with increase in superficial liquid velocity. The lower the superficial liquid velocity, the higher the slip but the lower the pressure gradient. Likewise, the lower the superficial liquid velocity, the more ripple waves obtained while the higher the superficial liquid velocity, the more disturbance waves in annular flow in horizontal pipe from the experiments.

Variation of Flow Regimes in +2 Degree Inclined Wet Gas Environments and Drag Reduction

2006 ◽  
Author(s):  
Cheolho Kang ◽  
Parimal More
Keyword(s):  
Pressure Gradient ◽  
Gas Phase ◽  
Slug Flow ◽  
Flow Characteristics ◽  
Phase Variation ◽  
Flow Patterns ◽  
Upward Flow ◽  
Wet Gas ◽  
Wave Forms ◽  
Flow Improver

Experiments were carried out to examine the study of flow patterns and the performance of drag reducing agents in a 40 m long, 10.16 cm diameter, + 2 degree inclined wet gas pipeline environments. Superficial liquid velocities ranging from 0.03 to 0.1 m/s and gas velocities from 2 to 10 m/s were investigated with the commercial DRA concentration of 0, 25 and 50 ppm. Light viscosity oil was used as the liquid phase and carbon dioxide was used as the gas phase. Variation of flow patterns in horizontal and +2 degree pipes are reported in this paper. The effect of inclinations on the pressure gradient is also presented. The stratified flow was dominant flow pattern in horizontal wet gas pipelines. However, for certain conditions, slug flow along with big wave forms was observed in 2 degree upward flow. The pressure gradient for 2 degree upward flow was higher than horizontal flow since the height of the liquid film was higher in case of upward flow. The pressure gradient decreased significantly as drag reducing agent was added in the pipeline. For slug flow in + 2 degree inclination, the pressure gradient reduction of 19 % was achieved for superficial liquid and gas velocities of 0.03 and 2 m/s at a flow improver concentration of 50 ppm. This was because the flow characteristics such as slug frequency and wave activity were changed with the addition of DRA.

Design and Performance of Slug Damper

2007 ◽  
Author(s):  
Antonio Reinoso ◽  
Luis E. Gomez ◽  
Shoubo Wang ◽  
Ram S. Mohan ◽  
Ovadia Shoham ◽  
...  
Keyword(s):  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate ◽  
Liquid Velocity ◽  
Flow Behavior ◽  
Mechanistic Model ◽  
Gas Velocity ◽  
Flow Loop ◽  
Two Phase ◽  
Superficial Gas Velocity

A novel flow conditioning device, namely, the slug damper, which can be used upstream of compact separation systems, is investigated theoretically and experimentally. In the experimental part, a 3” ID slug damper facility has been installed in an existing 2” diameter two-phase flow loop. This flow loop includes an upstream slug generator, a Gas-Liquid Cylindrical Cyclone (GLCC©) attached to the slug damper downstream, and a set of conductance probes for measuring the propagation of the dissipated slug along the damper. Over 200 experimental runs were conducted with artificially generated inlet slugs of 50 ft length (Ls/d = 300) that were dumped into the loop upstream of the slug damper, varying the superficial liquid velocity from 0.5 to 2.5 ft/s and superficial gas velocity between 10 to 40 ft/ (in the 2” inlet pipe) and utilizing segmented orifice opening heights of 1”, 1.5”, 2” and 3”. For each experimental run, the measured data included: propagation of the liquid slug front in the damper, differential pressure across the segmented orifice, GLCC liquid level, GLCC outlet liquid flow and static pressure in the GLCC. The data prove that the slug damper is capable of dissipating long slugs, ensuring fairly constant liquid flow rate into the downstream GLCC. Also, the damper capacity to process large slugs is a strong function of the superficial gas velocity (and mixture velocity). The theoretical part includes the development of a mechanistic model for the prediction of the hydrodynamic flow behavior in the slug damper. The model enables the predictions of the outlet liquid flow rate and the available damping time, and in turn the prediction of the slug damper capacity. Comparison between the model predictions and the acquired data reveals an accuracy of 30% with respect to the available damping time and outlet liquid flow rate. The developed model can be used for design of slug damper units in the field.

The dominant frequency analysis of interfacial wave in wet-gas pipeline transportation based on NIR absorption

2021 ◽  
pp. 1-10
Author(s):  
Zhiyue Zhao ◽  
Ning Zhao ◽  
Lide Fang ◽  
Xiaoting Li
Keyword(s):  
Liquid Film ◽  
Predictive Accuracy ◽  
Film Surface ◽  
Dominant Frequency ◽  
Wave Frequency ◽  
Interfacial Wave ◽  
Long Distance ◽  
Wet Gas ◽  
The Mean ◽  
Predictive Correlation

During the long-distance transportation of wet-gas, the dominant frequency is of great significance for the study of pipeline fatigue and damage, and the safety production. Therefore, the theoretical and experimental researches for dominant frequency are carried out increasingly. However, most of the current prediction correlation of dominant frequency are mainly applicable to atmospheric pressure conditions (0.1 MPa), and the prediction accuracy is not accurate enough. The paper obtains the time series signal of liquid film thickness by near-infrared (NIR) sensor, and then calculates the wave frequency by the power spectrum density (PSD). The performance of typical predictive correlation is evaluated and analyzed by utilizing the experimental data at different flow and pressure conditions (0.1–0.8) MPa. The structure of Strouhal number and Lockhart-Martinelli (L-M) parameter are optimized reasonably, the mean velocity of the liquid film surface, the density increment of gas core, the gas core mass flow and average liquid film velocity are considered in the L-M parameter, a modified interfacial wave frequency correlation is proposed. The results indicate that the mean absolute error of the predictive correlation is 9.06% (current data) and 25.64% (literature data). The new correlation has a better predictive accuracy.

scholarly journals Determinants of valve gating in collecting lymphatic vessels from rat mesentery

2011 ◽  
Vol 301 (1) ◽  
pp. H48-H60 ◽  
Author(s):  
Michael J. Davis ◽  
Elaheh Rahbar ◽  
Anatoliy A. Gashev ◽  
David C. Zawieja ◽  
James E. Moore
Keyword(s):  
Pressure Gradient ◽  
Muscle Tone ◽  
Lymphatic Vessels ◽  
Vessel Diameter ◽  
Intraluminal Pressure ◽  
Pressure Gradients ◽  
Rat Mesentery ◽  
Temporal Relationships ◽  
Wide Range ◽  
Valve Opening

Secondary lymphatic valves are essential for minimizing backflow of lymph and are presumed to gate passively according to the instantaneous trans-valve pressure gradient. We hypothesized that valve gating is also modulated by vessel distention, which could alter leaflet stiffness and coaptation. To test this hypothesis, we devised protocols to measure the small pressure gradients required to open or close lymphatic valves and determine if the gradients varied as a function of vessel diameter. Lymphatic vessels were isolated from rat mesentery, cannulated, and pressurized using a servo-control system. Detection of valve leaflet position simultaneously with diameter and intraluminal pressure changes in two-valve segments revealed the detailed temporal relationships between these parameters during the lymphatic contraction cycle. The timing of valve movements was similar to that of cardiac valves, but only when lymphatic vessel afterload was elevated. The pressure gradients required to open or close a valve were determined in one-valve segments during slow, ramp-wise pressure elevation, either from the input or output side of the valve. Tests were conducted over a wide range of baseline pressures (and thus diameters) in passive vessels as well as in vessels with two levels of imposed tone. Surprisingly, the pressure gradient required for valve closure varied >20-fold (0.1–2.2 cmH2O) as a passive vessel progressively distended. Similarly, the pressure gradient required for valve opening varied sixfold with vessel distention. Finally, our functional evidence supports the concept that lymphatic muscle tone exerts an indirect effect on valve gating.

Performance of Corrosion Inhibitors at High CO2 Pressures

2008 ◽  
Author(s):  
Patchareeporn Sintoorahat ◽  
Aree Wairatpanich ◽  
Suchada Chimam ◽  
Dayin Mongkholkhajornsilp ◽  
Cheolho Kang
Keyword(s):  
Corrosion Inhibitors ◽  
Liquid Velocity ◽  
Flow Characteristics ◽  
Stratified Flow ◽  
Inhibitor Concentration ◽  
Flow Loop ◽  
Corrosion Rates ◽  
Offshore Pipeline ◽  
Carbon Dioxide Pressure ◽  
Corrosion Rate Measurement

The objective of this study was to evaluate the performance of two corrosion inhibitors (CI-A and CI-B) under conditions similar to the second PTT’s offshore pipeline. The experiments were carried out in flow-loop system, 36 m long, 10.16 cm diameter at 10.5 and 14 bar of carbon dioxide pressure, a temperature at 50°C. The performances of corrosion inhibitors were examined under conditions of superficial liquid velocity of 0.03 m/s and gas velocities of 6, 8 and 10 m/s in 0 and 3 degree inclinations using the ER probe and X65 weight-loss coupons for corrosion rate measurement at the top and bottom of pipe. According to flow characteristics, it was found that the smooth and wavy stratified flow occurred in 0 degree. For 3 degree inclination, wavy stratified flow with big waves was dominantly presented for all conditions. Corrosion inhibitor B showed a better performance than inhibitor A in all cases. For inhibitor B, the target corrosion rates of less than 0.1 mm/yr were achieved in all conditions with 50 ppm of inhibitor concentration whereas the amount of 75 ppm inhibitor concentration was required for CI-A. The color, turbidity, and emulsion tendency with corrosion inhibitors will be also discussed in this paper.

Experimental Measurements and CFD Evaluation of the Onset Flow Boiling at Low Pressure and High Subcooling Flow of R-11 Within Vertical Annulus

2014 ◽  
Author(s):  
Y. Bouaichaoui ◽  
R. Kibboua ◽  
M. Matkovič
Keyword(s):  
Heat Flux ◽  
Liquid Velocity ◽  
Flow Boiling ◽  
Fluid Model ◽  
Computer Code ◽  
Computational Method ◽  
Subcooled Boiling ◽  
Two Phase ◽  
Local Flow ◽  
Wide Range

The knowledge of the onset of subcooled boiling in forced convective flow at high liquid velocity and subcooling is of importance in thermal hydraulic studies. Measurements were performed under various conditions of mass flux, heat flux, and inlet subcooling, which enabled to study the influence of different boundary conditions on the development of local flow parameters. Also, some measurements have been compared to the predictions by the three-dimensional two-fluid model of subcooled boiling flow carried out with the computer code ANSYS-CFX-13. A computational method based on theoretical studies of steady state two phase forced convection along a test section loop was released. The calculation model covers a wide range of two phase flow conditions. It predicts the heat transfer rates and transitions points such as the Onset of Critical Heat Flux.

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