Test Facility for Multiphase Flow Problems

2002 ◽  
Author(s):  
Charles L. Britton
Keyword(s):  
Multiphase Flow ◽  
Energy Content ◽  
Hydrate Formation ◽  
Test Facility ◽  
Operating Characteristics ◽  
Flowing Liquid ◽  
Physical Description ◽  
Flow Problems ◽  
Wet Gas ◽  
Gaseous Media

A physical description and the operating characteristics for a multiphase flow test facility are given. The facility is designed for wet-gas conditions where the gas-void-fraction (GVF) is typically greater than 0.95. However under many conditions, the liquid flowrate can be increased which results in a lower GVF. Lean natural gas, whose typical energy content is less than 1100 BTU/ft3, is used as the flowing gaseous media. The flowing liquid can range from a pure hydrocarbon liquid (such as decane) to a mixture of water and hydrocarbon liquids (condensate). Several investigations into the performance of various single-phase flowmeters and gas-liquid separators have been conducted for wet-gas flowing conditions. Present work includes the modification of the test facility to study hydrate formation and methods that can be employed to inhibit the hydrate formation. Visual images obtained with a high-pressure viewing section will be presented which show the different flow patterns that can exist within pipes that are contain multiphase fluids.

CFD Applied for the Identification of Stiffness and Damping Properties for Smooth Annular Turbomachinery Seals in Multiphase Flow

2016 ◽  
Author(s):  
Andreas Jauernik Voigt ◽  
Piero Iudiciani ◽  
Kenny Krogh Nielsen ◽  
Ilmar F. Santos
Keyword(s):  
Multiphase Flow ◽  
Volume Fraction ◽  
Bubbly Flow ◽  
Primary Phase ◽  
Test Facility ◽  
Liquid Volume ◽  
Shear Stresses ◽  
Liquid Volume Fraction ◽  
Wet Gas ◽  
Stiffness And Damping

This paper presents a first venture into quantifying stiffness and damping coefficients for turbomachinery seals in multiphase flow using Computational Fluid Dynamics (CFD). The study focusses on the simplest seal type: the smooth annular seal. The investigation is conducted for both wet-gas and bubbly flow regimes in which the primary phase is gas (air) and liquid (water), respectively. For the wet gas regime three different Liquid Volume Fraction (LVF) conditions are included in the study; 5%, 3% and 0%. Similarly for the bubbly flow regime three Gas Volume Fractions (GVF) conditions are included; 5%, 3% and 0%. An Eulerian-Eulerian modelling approach is taken, applying an inhomogeneous model, where the primary phase is treated as continuous and the secondary phase is included as dispersed. The Instationary Perturbation Method (IPM) is applied to identify the rotordynamic coefficients, in which the rotor is harmonically perturbed, and forces acting on the rotor are quantified through integration of the pressure and shear stresses. The perturbation is repeated for different frequencies to uncover any frequency dependence. The results presented in this paper are intended as an initial comparison basis for the experimental results to be obtained by applying the multiphase seal test facility currently in development, as part of a collaboration between Lloyd’s Register Consulting, the Technical University of Denmark, OneSubsea, TOTAL and Statoil.

An Experimental Investigation on Hysteresis in a Wet Gas Compressor

2017 ◽  
Author(s):  
Martin Bakken ◽  
Tor Bjørge
Keyword(s):  
Liquid Phase ◽  
Multiphase Flow ◽  
Open Loop ◽  
Operating Conditions ◽  
Test Facility ◽  
Centrifugal Impeller ◽  
Compression Process ◽  
Wet Gas ◽  
Liquid Load ◽  
Compressor Performance

Performance monitoring of wet gas compressors is challenging due to the liquid phase impact on performance. Introduction of a liquid phase alters both the thermodynamics as well as the fluid dynamics of the compression process. Hence, understanding the flow interaction between the impeller, diffuser and volute is pivotal. Previous investigations have detected occurrence of compressor hysteresis at certain wet gas operating conditions, resulting in temporary deviations from the steady state compressor characteristics. This kind of behavior influences both the compressor stability and performance. Thus, being able to understand the onset of hysteresis and its impact on the compressor is paramount. An experimental test campaign has been performed at the Norwegian University of Science and Technology (NTNU). The test facility is an open loop configuration consisting of a shrouded centrifugal impeller, a vaneless diffuser and a circular volute. The current investigation document the compressor performance shift and the occurrence of compressor hysteresis when gradually increasing the liquid load on a centrifugal compressor. Emphasis was put on the compressor performance and its correlation to the diffuser multiphase flow regime. The investigation revealed that there is a clear dependence between the diffuser multiphase flow characteristics and the compressor performance.

Coupled Heat and Mass Transfer CFD Model for Methane Hydrate

2015 ◽  
Author(s):  
Eugenio Turco Neto ◽  
M. A. Rahman ◽  
Syed Imtiaz ◽  
Thiago dos Santos Pereira ◽  
Fernanda Soares de Sousa
Keyword(s):  
Natural Gas ◽  
Multiphase Flow ◽  
Gas Hydrate ◽  
Gas Flow ◽  
Three Dimensional ◽  
Hydrate Formation ◽  
Cfd Model ◽  
Flow Metering ◽  
Ansys Cfx ◽  
Gas Hydrate Formation

The gas hydrates problem has been growing in offshore deep water condition where due to low temperature and high pressure hydrate formation becomes more favorable. Several studies have been done to predict the influence of gas hydrate formation in natural gas flow pipeline. However, the effects of multiphase hydrodynamic properties on hydrate formation are missing in these studies. The use of CFD to simulate gas hydrate formation can overcome this gap. In this study a computational fluid dynamics (CFD) model has been developed for mass, heat and momentum transfer for better understanding natural gas hydrate formation and its migration into the pipelines using ANSYS CFX-14. The problem considered in this study is a three-dimensional multiphase-flow model based on Simon Lo (2003) study, which considered the oil-dominant flow in a pipeline with hydrate formation around water droplets dispersed into the oil phase. The results obtained in this study will be useful in designing a multiphase flow metering and a pump to overcome the pressure drop caused by hydrate formation in multiphase petroleum production.

Wet Gas Impeller Test Facility

2010 ◽  
Author(s):  
Trond G. Gru¨ner ◽  
Lars E. Bakken
Keyword(s):  
Oil And Gas ◽  
Fluid Dynamic ◽  
Open Loop ◽  
Gas Production ◽  
Test Facility ◽  
Atmospheric Conditions ◽  
Oil And Gas Production ◽  
Wet Gas ◽  
Inlet Conditions ◽  
The Impact

The development of wet gas compressors will enable increased oil and gas production rates and enhanced profitable operation by subsea well-stream boosting. A more fundamental knowledge of the impact of liquid is essential with regard to the understanding of thermodynamic and fluid dynamic compressor behavior. An open-loop impeller test facility was designed to investigate the wet gas performance, aerodynamic stability, and operation range. The facility was made adaptable for different impeller and diffuser geometries. In this paper, the wet gas test facility and experimental work concerning the impact of wet gas on a representative full-scale industrial impeller are presented. The centrifugal compressor performance was examined at high gas volume fractions and atmospheric inlet conditions. Air and water were used as experimental fluids. Dry and wet gas performance was experimentally verified and analyzed. The results were in accordance with previous test data and indicated a stringent influence of the liquid phase. Air/water tests at atmospheric conditions were capable of reproducing the general performance trend of hydrocarbon wet gas compressor tests at high pressure.

scholarly journals Study of hydrate formation in gas-emulsion multiphase flow systems

RSC Advances ◽  
2017 ◽  
Vol 7 (76) ◽  
pp. 48127-48135 ◽  
Author(s):  
Chaoyu Ruan ◽  
Lin Ding ◽  
Bohui Shi ◽  
Qiyu Huang ◽  
Jing Gong
Keyword(s):  
Multiphase Flow ◽  
Flow System ◽  
Hydrate Formation ◽  
System P ◽  
Flow Systems

Hydrate crystallization and formation in a gas and WO emulsion multiphase flow system.

Sizing Wet-Gas Pipelines and Slug Catchers With Steady-State Multiphase Flow Simulations

1998 ◽  
Vol 120 (2) ◽  
pp. 106-110 ◽  
Author(s):  
J. J. Xiao ◽  
G. Shoup
Keyword(s):  
Steady State ◽  
Multiphase Flow ◽  
Simulation Models ◽  
Gas Pipelines ◽  
Flow Simulations ◽  
Wet Gas ◽  
Starting Point ◽  
Operational Information ◽  
Exit Speed ◽  
Steady State Simulation

The design of wet-gas pipelines and slug catchers requires multiphase flow simulations, both steady-state and transient. However, steady-state simulation is often inadequately conducted and its potential not fully utilized. This paper shows how mechanistic steady-state simulation models can be used to obtain not only pressure drop, liquid holdup and flow regime, but also to extract important operational information such as pig transit time, pig exit speed, liquid buildup rate behind the pig, and the time for the pipeline to return to a steady-state after pigging. A well-designed set of steady-state simulations helps to determine pipeline size, slug catcher size, and pigging frequency. It also serves as a starting point for subsequent transient multiphase flow simulations.

A Model of Multiphase Flow Dynamics Considering the Hydrated Bubble Behaviors and Its Application to Deepwater Kick Simulation

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Xiaohui Sun ◽  
Baojiang Sun ◽  
Yonghai Gao ◽  
Zhiyuan Wang
Keyword(s):  
Heat Transfer ◽  
Multiphase Flow ◽  
Void Fraction ◽  
Mass Transfer Rate ◽  
Hydrate Formation ◽  
Flow Dynamics ◽  
Fluid Temperature ◽  
Hydrate Shell ◽  
Free Gas ◽  
Mass And Heat Transfer

The interaction between hydrated bubble growth and multiphase flow dynamics is important in deepwater wellbore/pipeline flow. In this study, we derived a hydrate shell growth model considering the intrinsic kinetics, mass and heat transfer, and hydrodynamics mechanisms in which a partly coverage assumption is introduced for elucidating the synergy of bubble hydrodynamics and hydrate morphology. Moreover, a hydro-thermo-hydrate model is developed considering the intercoupling effects including interphase mass and heat transfer, and the slippage of hydrate-coated bubble. Through comparison with experimental data, the performance of proposed model is validated and evaluated. The model is applied to analyze the wellbore dynamics process of kick evolution during deepwater drilling. The simulation results show that the hydrate formation region is mainly near the seafloor affected by the fluid temperature and pressure distributions along the wellbore. The volume change and the mass transfer rate of a hydrated bubble vary complicatedly, because of hydrate formation, hydrate decomposition, and bubble dissolution (both gas and hydrate). Moreover, hydrate phase transition can significantly alter the void fraction and migration velocity of free gas in two aspects: (1) when gas enters the hydrate stability field (HSF), a solid hydrate shell will form on the gas bubble surface, and thereby, the velocity and void fraction of free gas can be considerably decreased; (2) the free gas will separate from solid hydrate and expand rapidly near the sea surface (outside the HSF), which can lead to an abrupt hydrostatic pressure loss and explosive development of the gas kick.

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