Modelling Downhole Separation Efficiency Using a Stream Function Approach

2009 ◽  
Author(s):  
Richard Marquez ◽  
Mauricio Gargaglione Prado
Keyword(s):  
Experimental Data ◽  
Stream Function ◽  
Separation Efficiency ◽  
Vertical Direction ◽  
Function Approach ◽  
Momentum Balance ◽  
Two Phase ◽  
Natural Separation ◽  
A New Technique ◽  
The University

A new technique for solving simultaneously the mass and momentum balance equations for a gas-liquid mixture is proposed in this paper. The technique is based on the vorticity-stream function approach, under a cylindrical coordinate system. Important variables such as slip velocity in the radial and vertical direction, characteristic of the bottomhole, gas and liquid flow rates, pressures, flow pattern, among others, are considered simultaneously in the solution of the problem. The two-phase model proposed in this work allows obtaining the liquid and gas velocities fields as well as the two-phase flow pressure and gas fraction fields. Experimental data is used to close the model. The model was used to simulate downhole separation efficiency and to determine the influence of liquid flowrate, GLR, casing size and liquid viscosity on the natural separation efficiency. The model agrees very well with experimental data obtained by The University of Tulsa.

Use of a Bubble Tracking Method for Prediction of Downhole Natural Separation Efficiency

2005 ◽  
Vol 127 (4) ◽  
pp. 479-486
Author(s):  
Bin Liu ◽  
Mauricio Prado
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Single Phase ◽  
Two Phase Flow ◽  
Separation Efficiency ◽  
Phase Flow ◽  
Two Phase ◽  
Tracking Method ◽  
Wide Range ◽  
Natural Separation

For any pumping artificial lift system in the petroleum industry, the free gas significantly affects the performance of the pump and the system above the pump. A model, though not a complete two-phase flow model, has been developed for the effective prediction of separation efficiency across a wide range of production conditions. The model presented is divided into two main parts, the single-phase flow-field solution and the bubble-tracking method. The first part of the model solves the single-phase liquid flow field using the computational fluid dynamics approach. Then, a simple bubble-tracking method was applied to estimate the down-hole natural separation efficiency for two-phase flow. A comparison between the results of the model and the experimental data was conducted. It shows a very good agreement with the experimental data for lower gas void fractions (bubble flow regime).

Modeling Downhole Natural Separation Using a Bubble Tracking Method

2004 ◽  
Author(s):  
Bin Liu ◽  
Mauricio Prado
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Single Phase ◽  
Two Phase Flow ◽  
Separation Efficiency ◽  
Phase Flow ◽  
Two Phase ◽  
Tracking Method ◽  
Wide Range ◽  
Natural Separation

For any pumping artificial lift system in petroleum industry, the free gas significantly affects the performance of the pump and the system above the pump. A model, though not a complete two-phase flow model, has been developed for the effective prediction of separation efficiency across a wide range of production conditions. The model presented is divided into two main parts, the single-phase flow field solution and the bubble tracking method. The first part of the model solves the single-phase liquid flow field using the CFD approach. Then, a simple bubble-tracking method was applied to estimate the down-hole natural separation efficiency for two-phase flow. A comparison between the results of the model and the experimental data was conducted. It shows a very good agreement with the experimental data for lower gas void fractions (bubble flow regime).

Experimental and Numerical Investigation of Air-Particle Two-Phase Flow in Centrifugal Separator

2000 ◽  
Author(s):  
H. J. Kang ◽  
B. Zheng ◽  
C. X. Lin ◽  
M. A. Ebadian
Keyword(s):  
Velocity Distribution ◽  
Separation Efficiency ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Tangential Direction ◽  
Cylinder Surface ◽  
Centrifugal Separator ◽  
Two Phase ◽  
Dust Collection ◽  
Numerical Solver

Abstract The velocity distributions inside a centrifugal separator with outside and inside diameters of 152.4 mm (6″) and 76.2 mm (3″), respectively, have been investigated experimentally and numerically to obtain optimum separation efficiency. Two 12.7 mm (1/2-inch) holes were drilled on the external surface of the separator to measure the velocity distribution in the separator. Two direction velocities (tangential direction along the cylinder surface and axial along the vertical direction) were measured to compare with the numerical simulation results. A 6060P Pitot probe was employed to obtain the velocity distribution. The dust samples (a mixture of steel particle and dust) from the dust collection box were analyzed using a Phillips XL30 Scanning Electron Microscope. FLUENT code is used as the numerical solver for this fully three-dimensional problem. The fluid flow in the separator is assumed to be steady and incompressible turbulent flow. The standard k–ε model was employed in this study. Non-uniform, unstructured grids are chosen to discretize the entire computation domain. Almost 100,000 cells are used to discretize the whole separator. The constant velocity profile is imposed on the inlet plane. The pressure boundary condition is adopted at outlet plane. Comparing the velocity distribution and separation efficiency from the experiment and the numerical modeling shows that the experimental results and the estimated data agree fairly well and with a deviation within ±10%.

The Comparison with Numerical Simulation Results of Steam-Water Flow Field and Experimental Data for Car Exhaust Pipe

2011 ◽  
Vol 187 ◽  
pp. 570-574
Author(s):  
Qing Guo Liu ◽  
Yan Ma ◽  
Chun Mei Yang
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Flow Field ◽  
Separation Efficiency ◽  
Tangential Velocity ◽  
Exhaust Pipe ◽  
Two Phase ◽  
Car Exhaust ◽  
Simulation Results ◽  
The Relationship

In this paper, the physical model for flow field of exhaust pipe has been established on the condition of a liquid-gas exhaust pipe from cars using ethanol gasoline. The numerical simulation results for internal flow field of car exhaust pipe are compared with the experimental data. It is showed that the outside free vortex tangential velocity and axial velocity of single-phase flow field have been simulated better. It is indicated in the simulation of separation process of steam-water two-phase: The relative error, comparing the relationship between flow and separation efficiency with measured of that is less than 7%, and the same to 15%, comparing the relationship between flow and separation ratio with measured of that. Thereby, it is confirmed correctly for the mathematical model founded for numerical calculation and the algorithm selected.

A Technique for the Laboratory Determination of Recirculation in Single Needle Dialysis

1993 ◽  
Vol 16 (2) ◽  
pp. 63-70 ◽  
Author(s):  
N.A. Hoenich ◽  
P.T. Smirthwaite ◽  
C. Woffindin ◽  
P. Lancaster ◽  
T.H. Frost ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Experimental Results ◽  
New Technique ◽  
Treatment Efficiency ◽  
Single Lumen ◽  
Theoretical Predictions ◽  
Lumen Catheter ◽  
A New Technique

Recirculation is an important factor in single needle dialysis and, if high, can compromise treatment efficiency. To provide information regarding recirculation characteristics of access devices used in single needle dialysis, we have developed a new technique to characterise recirculation and have used this to measure the recirculation of a Terumo 15G fistula needle and a VasCath SC2300 single lumen catheter. The experimentally obtained results agreed well with those established clinically (8.5 ± 2.4% and 18.4 ± 3.4%). The experimental results have also demonstrated a dependence on access type, pump speeds and fistula flow rate. A comparison of experimental data with theoretical predictions showed that the latter exceeded those measured with the largest contribution being due to the experimental fistula.

Development and Validation of a Three-Dimensional Multiphase Flow CFD Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

2012 ◽  
Author(s):  
Stephan Uhkoetter ◽  
Stefan aus der Wiesche ◽  
Michael Kursch ◽  
Christian Beck
Keyword(s):  
Experimental Data ◽  
Multiphase Flow ◽  
Gas Turbines ◽  
High Speed ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Present Contribution ◽  
Two Phase

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach including cavitation and air entrainment for high-speed turbo-machinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty type gas turbine journal bearings.

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