An Innovative Two-Phase Flow Pump and Separator Solution

2011 ◽  
Author(s):  
Franc¸ois Gruselle ◽  
Johan Steimes ◽  
Patrick Hendrick
Keyword(s):  
Flow Rate ◽  
Flow Model ◽  
Two Phase Flow ◽  
Volume Fraction ◽  
Operating Conditions ◽  
Liquid Volume ◽  
Phase Flow ◽  
Two Phase ◽  
Efficient System ◽  
Measurement Systems

The Aero-Thermo-Mechanics (ATM) department of Universite´ Libre de Bruxelles (ULB) develops a new system to simultaneously pump and separate a two-phase flow, in particular oil/air mixtures. Two-phase flows are encountered in many applications (oil extraction, flow in nuclear power plant pumps, pulp and paper processing) but the study is mainly focused on aeroengine lubrication systems. The main objective is to obtain a compact and efficient system that can both extract the gas of a two-phase flow and increase the pressure of the liquid phase. Particular care is given to the liquid flow rate lost at the gas outlet of the system. A large range of gas/liquid volume ratio has been studied, leading to different two-phase flow regimes at the inlet of the system (slug, churn or annular flow). After successful tests with water-air prototypes, which have allowed to identify the key design and working parameters, the technology has been implemented for a hot oil-air mixture. This paper presents the test results of the first oil/air prototype under real in-flight operating conditions. The tests with oil/air mixtures were performed on the aeroengine lubrication system test bench of the ATM department. The identification and implementation of appropriate two-phase flow rate measurement systems is an essential contribution to the project. Two attractive measurement systems have been considered: a Coriolis density meter for the volume fraction at the liquid outlet and radio-tracing elements for the measurement of the oil consumption at the air outlet. In parallel, the flow field in the pump and separator system has been studied with commercial CFD (Computational Fluid Dynamics) software packages. The choice of the two-phase flow model is highly dependent on the two-phase flow regime. But different regimes can simultaneously exist in the pump and separator system. So, the Eulerian two-phase flow model, the most complex and general model, seems to be the most appropriate. A coupling of this model with a dispersed phase model is under investigation to take all two-phase flow phenomena into account.

Visual Criteria for Measuring Two-phase Flow Rate in Venturi with Flow Homogenizer

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Sangho Sohn ◽  
Jaebum Park ◽  
Dong-Wook Oh
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Two Phase Flow ◽  
Volume Fraction ◽  
Differential Pressure ◽  
Phase Flow ◽  
Two Phase ◽  
3 Dimensional ◽  
Lower Amplitude ◽  
Gas Volume

A simple use of Venturi might be used to measure two-phase flow rate within relatively low GVF(gas volume fraction). Upstream flow entering Venturi can be improved with installed flow homogenizer which is easily fabricated by 3-dimensional printer with multiple holes. Simultaneous measurement between high-speed flow visualization and dynamic differential pressure measurement was made to find visual criteria for two-phase flow rate measurement with different GVF ranged from 0% to 30%. It was observed that the two-phase flow rate can be reliably measured up to 15% of GVF using flow homogenizer. FFT(Fast-Fourier Transform) results proved that the long flow homogenizers (type 2 and 4) showed a lower amplitude of differential pressure (Δp) than the short flow homogenizers (type 1 and 3) respectively. So the optimized flow homogenizer can be useful to measure two-phase flow rate at low GVF.

Study of Uneven Distribution in Parallel Petroleum Processing Pipes

2016 ◽  
Author(s):  
Renwei Liu ◽  
Haishan Zhu ◽  
Qingping Li ◽  
Yufei Wan ◽  
Kaifeng Fan
Keyword(s):  
Flow Rate ◽  
Two Phase Flow ◽  
Operating Conditions ◽  
Uneven Distribution ◽  
Petroleum Processing ◽  
Phase Flow ◽  
Operating Pressure ◽  
Two Phase ◽  
Specific Flow ◽  
Central Platform

The aim of this article is to investigate uneven distribution of oil-gas two phase flow in parallel petroleum processing pipelines. On-site analysis on BZ35-2 central platform A and SZ36-1 central platform N/O (two typical platforms in China’s Bohai Bay) shows that uneven distribution is originated mainly by two sources: flow rate difference and dryness difference. A 3-dimensional numerical model of two-phase flow in T-junction before parallel processing units was built. Flow and dryness distribution under different operating conditions were simulated. It is demonstrated that unevenness of flow rate grows worse as the total flow rate increases or operating pressure difference between parallel units becomes larger. Moreover, unevenness of dryness is mainly caused by phase split in a tee. It can be concluded that the phase split will be more obvious when parallel units are located at different heights or gas volume fraction of feed stream and inlet flow rate is small. Besides, flow rate distribution has an effect on dryness distribution. There is a specific flow ratio that will cause the most serious phase split. Finally, according to the conclusions, modification scheme for BZ35-2 central platform A piping layout was proposed. And this work may provide some guidance for process design and practical operation of parallel units.

An Analytical Two-Phase Flow Model for Prediction of Leakage in Wet Gas Labyrinth Seals and Pocket Damper Seals. Is Simplicity Still Desired?

2021 ◽  
Author(s):  
Jing Yang ◽  
Luis San Andrés
Keyword(s):  
Simple Model ◽  
Two Phase Flow ◽  
Volume Fraction ◽  
Liquid Volume ◽  
Gas Mixture ◽  
Phase Flow ◽  
Rotor Speed ◽  
Labyrinth Seals ◽  
Two Phase ◽  
Wet Gas

Abstract Current and upcoming two-phase pump and compression systems in subsea production facilities must demonstrate long-term operation and continuous availability. Annular pressure seals, limiting secondary flow, also influence the dynamic stability of turbomachinery. Hence, it becomes paramount to quantify the leakage and dynamic force coefficients of annular seals operating with two-phase flow, a liquid in gas mixture or wet gas. Until now, a simple model for labyrinth seals (LSs) and the more modern pocket damper seals (PDSs) is not available, though these seal types find wide applications in subsea machinery. The paper develops a simple analytical model predicting the leakage and cavity pressures for LSs and PDSs operating with two-phase flow. The model adapts Neumann’s leakage equation for use with the physical properties of a homogeneous two-phase flow mixture. Predictions of leakage for a four-blade, eight-pocket, fully partitioned PDS operating under a low supply pressure (PS = 2.3 bar and 3.2 bar) and a low rotor speed equal to 5,250 rpm (surface speed = 35 m/s) agree well with experimental results procured for both a pure gas and a wet gas conditions (2.2% in liquid volume). Predicted leakage and cavity pressures also agree with those found by a multi-million node computational fluid dynamics (CFD) model. For an eight-blade, sixteen-pocket PDS supplied with air at PS = 62.1 bar, discharge pressure Pa = 31.1 bar and rotor speed of 15 krpm (surface speed = 91 m/s), the analytical model predicts leakage that is just 2% larger than a published CFD prediction. For the PDS supplied with an oil in gas mixture having gas volume fraction βS = 0.92 ∼ 0.98, the simple model delivers leakage that is up to ∼ 6% lower than published CFD results. An analysis of the two-phase leakage predictions via a modified flow factor reveals a loss coefficient (cd) impervious to the range of supply and discharge pressures considered and growing in proportion to the liquid volume fraction. Throughout the life of an oil well that sees radical changes in gas and liquid composition as well as pressure conditions, the expedient model, quick and accurate to estimate leakage in wet gases seals, can be readily integrated into an engineering routine or practice.

scholarly journals Two-Way Coupling Simulation of Solid-Liquid Two-Phase Flow and Wear Experiments in a Slurry Pump

2022 ◽  
Vol 10 (1) ◽  
pp. 57
Author(s):  
Lei Jiang ◽  
Ling Bai ◽  
Peng Xue ◽  
Guangjie Peng ◽  
Ling Zhou
Keyword(s):  
Two Phase Flow ◽  
Volume Fraction ◽  
Volume Flow Rate ◽  
Pure Water ◽  
Solid Volume Fraction ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Phase Flow ◽  
Two Phase ◽  
Solid Liquid

The slurry pump is one of the most important pieces of equipment in mineral transportation and separation systems, and it has complex two-phase flow characteristics and wear mechanisms. By employing numerical and experimental methods, the solid–liquid two-phase flow characteristics and wear patterns were investigated in this study. A two-way coupling discrete phase model (DPM) method was used to predict the flow pattern and the wear location and shows good agreement with the experimental observations. The pump performance characteristics of numerical results under pure water conditions were consistent with the experimental results. The effects of particle parameters and operating conditions on the internal flow field and wear were compared and discussed. The results show that the wear degree increased with the increase in volume flow rate and solid volume fraction. With the increase in particle size, the wear range at the impeller inlet became significantly smaller, but the wear degree became obviously larger. This study provides a basis for reducing the wear and improving the hydraulic performance of slurry pumps.

An Analytical Two-Phase Flow Model for Prediction of Leakage in Wet Gas Labyrinth Seals and Pocket Damper Seals. Is Simplicity Still Desired?

2021 ◽  
Author(s):  
Jing Yang ◽  
Luis San Andres
Keyword(s):  
Analytical Model ◽  
Flow Model ◽  
Two Phase Flow ◽  
Volume Fraction ◽  
Gas Mixture ◽  
Phase Flow ◽  
Rotor Speed ◽  
Labyrinth Seals ◽  
Two Phase ◽  
Wet Gas

Abstract Current and upcoming two-phase pump and compression systems in subsea production facilities must demonstrate long-term operation and continuous availability. Annular pressure seals, limiting secondary flow, also influence the dynamic stability of turbomachinery. Hence, it becomes paramount to quantify the leakage and dynamic performance of annular seals operating with a liquid in gas mixture (wet gas). The paper develops a simple analytical model predicting the leakage and cavity pressures for Labyrinth seals and pocket damper seals (PDSs) operating with two-phase flow. The model adapts Neumann's equation with a homogeneous flow model. Predicted leakage for a four-blade PDS operating under a low supply pressure (2.3 and 3.2 bar) and a low rotor speed (5,250 rpm) agree well with experimental results for both a pure gas and a wet gas conditions. For an eight-blade PDS supplied with air at 62.1 bar, discharge pressure 31.1 bar and rotor speed of 15 krpm, the analytical model predicts leakage that is just 2% larger than a CFD prediction. For the PDS supplied with an oil in gas mixture having gas volume fraction = 0.92 ~ 0.98, the simple model delivers leakage that is up to ~ 6% lower than published CFD results. Throughout the life of an oil well that sees radical changes in gas and liquid composition as well as pressure conditions, the expedient model, quick and accurate to estimate leakage in wet gases seals, can be readily integrated into an engineering routine or practice.

Two-phase modelling of a fluid mixing layer

1999 ◽  
Vol 378 ◽  
pp. 119-143 ◽  
Author(s):  
J. GLIMM ◽  
D. SALTZ ◽  
D. H. SHARP
Keyword(s):  
Boundary Conditions ◽  
Flow Model ◽  
Two Phase Flow ◽  
Volume Fraction ◽  
Mixing Layer ◽  
Constitutive Law ◽  
Fluid Mixing ◽  
Phase Flow ◽  
Two Phase ◽  
Self Similar Solution

We analyse and improve a recently-proposed two-phase flow model for the statistical evolution of two-fluid mixing. A hyperbolic equation for the volume fraction, whose characteristic speed is the average interface velocity v*, plays a central role. We propose a new model for v* in terms of the volume fraction and fluid velocities, which can be interpreted as a constitutive law for two-fluid mixing. In the incompressible limit, the two-phase equations admit a self-similar solution for an arbitrary scaling of lengths. We show that the constitutive law for v* can be expressed directly in terms of the volume fraction, and thus it is an experimentally measurable quantity. For incompressible Rayleigh–Taylor mixing, we examine the self-similar solution based on a simple zero-parameter model for v*. It is shown that the present approach gives improved agreement with experimental data for the growth rate of a Rayleigh–Taylor mixing layer.Closure of the two-phase flow model requires boundary conditions for the surfaces that separate the two-phase and single-phase regions, i.e. the edges of the mixing layer. We propose boundary conditions for Rayleigh–Taylor mixing based on the inertial, drag, and buoyant forces on the furthest penetrating structures which define these edges. Our analysis indicates that the compatibility of the boundary conditions with the two-phase flow model is an important consideration. The closure assumptions introduced here and their consequences in relation to experimental data are compared to the work of others.

A ONE-DIMENSIONAL TWO-PHASE FLOW MODEL AND EXPERIMENTAL VALIDATION FOR A FLASHING VISCOUS LIQUID IN A SPLASH PLATE NOZZLE

2015 ◽  
Vol 25 (9) ◽  
pp. 795-817 ◽  
Author(s):  
Mika P. Jarvinen ◽  
A. E. P. Kankkunen ◽  
R. Virtanen ◽  
P. H. Miikkulainen ◽  
V. P. Heikkila
Keyword(s):  
Viscous Liquid ◽  
Experimental Validation ◽  
Flow Model ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
One Dimensional
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