Bubble Analogy and Stabilization of Core-Annular Flow

2000 ◽  
Vol 123 (2) ◽  
pp. 127-132 ◽  
Author(s):  
Antonio C. Bannwart
Keyword(s):  
Cross Section ◽  
Annular Flow ◽  
Momentum Conservation ◽  
Conservation Equation ◽  
Interface Shape ◽  
Laboratory Measurements ◽  
Horizontal Pipe ◽  
The Core ◽  
Oil Water ◽  
Momentum Conservation Equation

A theory for the stabilization of annular liquid-liquid flow (i.e., core-annular flow) in a horizontal pipe is proposed. Based upon the analysis of the momentum conservation equation in the cross section of the flow, including the effects of peripheral flow in the annulus and interfacial tension, an equation is obtained which describes the interface shape. Results for the height-to-width aspect ratio of the core are compared with laboratory measurements done by the author for a heavy oil-water core-annular flow. A criterion for stabilization of this interesting flow pattern is proposed.

Effects of Non-Linearity of the Momentum Conservation Equation During Electrokinetic Transport in Nano and Microchannels

2010 ◽  
Author(s):  
Subir Bhattacharjee ◽  
Noor Al Quddus
Keyword(s):  
Porous Media ◽  
Electric Fields ◽  
Stokes Equations ◽  
Momentum Conservation ◽  
Conservation Equation ◽  
Small Scale ◽  
Electrokinetic Transport ◽  
Electrokinetic Flow ◽  
Non Linear ◽  
Momentum Conservation Equation

Electrokinetic transport phenomena, such as electroosmosis, streaming potential, electrophoresis, and sedimentation potential, are central to many micro- and nano-channel flows. During continuum modeling of such phenomena, incorporation of the electrical body force term can make the fluid momentum conservation equation highly non-linear. This non-linearity is often ignored in small-scale electrokinetic flow modeling because of our implicit reliance on the linearity of the Stokes equations for low Reynolds number flows. In this paper, ramifications of this non-linear Stokes equation in electrokinetic flows will be described with examples of our recent studies on pressure driven flows through porous media for electrokinetic power generation, electroosmotic flow of charged entities in nanochannels, and flow of DNA through self-assembled porous media under pulsed electric fields.

Experimental and Simulated Studies of Oil/Water Fully Dispersed Flow in a Horizontal Pipe

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
D. S. Santos ◽  
P. M. Faia ◽  
F. A. P. Garcia ◽  
M. G. Rasteiro
Keyword(s):  
Pressure Drop ◽  
Drag Coefficient ◽  
Cross Section ◽  
Numerical Study ◽  
Liquid Paraffin ◽  
Water Mixture ◽  
Horizontal Pipe ◽  
Dispersed Flow ◽  
Oil Water ◽  
Mixture Viscosity

The flow of oil/water mixtures in a pipe can occur under different flow patterns. Additionally, being able to predict adequately pressure drop in such systems is of relevant importance to adequately design the conveying system. In this work, an experimental and numerical study of the fully dispersed flow regime of an oil/water mixture (liquid paraffin and water) in a horizontal pipe, with concentrations of the oil of 0.01, 0.13, and 0.22 v/v were developed. Experimentally, the values of pressure drop, flow photographs, and radial volumetric concentrations of the oil in the vertical diameter of the pipe cross section were collected. In addition, normalized conductivity values were obtained, in this case, for a cross section of the pipe where an electrical impedance tomography (EIT) ring was installed. Numerical studies were carried out in the comsolmultiphysics platform, using the Euler–Euler approach, coupled with the k–ε turbulence model. In the simulations, two equations for the calculation of the drag coefficient, Schiller–Neumann and Haider–Levenspiel, and three equations for mixture viscosity, Guth and Simba (1936), Brinkman (1952), and Pal (2000), were studied. The simulated data were validated with the experimental results of the pressure drop, good results having been obtained. The best fit occurred for the simulations that used the Schiller–Neumann equation for the calculation of the drag coefficient and the Pal (2000) equation for the mixture viscosity.

Experimental study on highly viscous oil-water annular flow in a horizontal pipe with 90° elbow

2021 ◽  
Vol 135 ◽  
pp. 103499
Author(s):  
Jiaqiang Jing ◽  
Xiaoyun Yin ◽  
Boris N. Mastobaev ◽  
Anvar R. Valeev ◽  
Jie Sun ◽  
...  
Keyword(s):  
Experimental Study ◽  
Annular Flow ◽  
Horizontal Pipe ◽  
Viscous Oil ◽  
Oil Water ◽  
Highly Viscous Oil

The coordinated motion planning of a dual-arm space robot for target capturing

Robotica ◽  
2011 ◽  
Vol 30 (5) ◽  
pp. 755-771 ◽  
Author(s):  
Wenfu Xu ◽  
Yu Liu ◽  
Yangsheng Xu
Keyword(s):  
Center Of Mass ◽  
Momentum Conservation ◽  
Conservation Equation ◽  
Space Robot ◽  
Coordinated Motion ◽  
First Case ◽  
Solution Equation ◽  
Target Capturing ◽  
Dual Arm ◽  
Momentum Conservation Equation

SUMMARYIn this paper, autonomous motion control approaches to generate the coordinated motion of a dual-arm space robot for target capturing are presented. Two typical cases are studied: (a) The coordinated dual-arm capturing of a moving target when the base is free-floating; (b) one arm is used for target capturing, and the other for keeping the base fixed inertially. Instead of solving all the variables in a unified differential equation, the solution equation of the first case is simplified into two sub-equations and practical methods are used to solve them. Therefore, the computation loads are largely reduced, and feasible trajectories can be determined. For the second case, we propose to deal with the linear and angular momentums of the system separately. The linear momentum conservation equation is used to design the configuration and the mounted pose of a balance arm to keep the inertial position of the base's center of mass, and the angular momentum conservation equation is used to estimate the desired momentum generated by the reaction wheels for maintaining the inertial attitude of the base. Finally, two typical tasks are simulated. Simulation results verify the corresponding approaches.

scholarly journals Influence of oil viscosity on oil-water core-annular flow through a horizontal pipe

Petroleum ◽  
2019 ◽  
Vol 5 (2) ◽  
pp. 199-205 ◽  
Author(s):  
Erik van Duin ◽  
Ruud Henkes ◽  
Gijs Ooms
Keyword(s):  
Annular Flow ◽  
Oil Viscosity ◽  
Horizontal Pipe ◽  
Flow Through ◽  
Oil Water

Inception and termination of the core-annular flow pattern for oil-water downflow through a vertical pipe

AIChE Journal ◽  
2011 ◽  
Vol 58 (7) ◽  
pp. 2020-2029 ◽  
Author(s):  
Sumana Ghosh ◽  
Gargi Das ◽  
Prasanta Kumar Das
Keyword(s):  
Flow Pattern ◽  
Annular Flow ◽  
Vertical Pipe ◽  
The Core ◽  
Oil Water

scholarly journals Thermodynamically consistent Darcy–Brinkman–Forchheimer framework in matrix acidization

2021 ◽  
Vol 76 ◽  
pp. 8
Author(s):  
Yuanqing Wu ◽  
Jisheng Kou ◽  
Shuyu Sun ◽  
Yu-Shu Wu
Keyword(s):  
Numerical Experiments ◽  
Good Description ◽  
Energy Balance Equation ◽  
Momentum Conservation ◽  
Conservation Equation ◽  
Scale Model ◽  
Recovery Stage ◽  
Tertiary Recovery ◽  
Matrix Acidization ◽  
Momentum Conservation Equation

Matrix acidization is an important technique used to enhance oil production at the tertiary recovery stage, but its numerical simulation has never been verified. From one of the earliest models, i.e., the two-scale model (Darcy framework), the Darcy–Brinkman–Forchheimer (DBF) framework is developed by adding the Brinkman term and Forchheimer term to the momentum conservation equation. However, in the momentum conservation equation of the DBF framework, porosity is placed outside of the time derivation term, which prevents a good description of the change in porosity. Thus, this work changes the expression so that the modified momentum conservation equation can satisfy Newton’s second law. This modified framework is called the improved DBF framework. Furthermore, based on the improved DBF framework, a thermal DBF framework is given by introducing an energy balance equation to the improved DBF framework. Both of these frameworks are verified by former works through numerical experiments and chemical experiments in labs. Parallelization to the complicated framework codes is also realized, and good scalability can be achieved.

scholarly journals Hydrodynamic Modeling of Oil–Water Stratified Smooth Two-Phase Turbulent Flow in Horizontal Circular Pipes

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5201
Author(s):  
Qi Kang ◽  
Jiapeng Gu ◽  
Xueyu Qi ◽  
Ting Wu ◽  
Shengjie Wang ◽  
...  
Keyword(s):  
Turbulent Flow ◽  
Pressure Gradient ◽  
Cross Section ◽  
Volume Flow Rate ◽  
Horizontal Tube ◽  
Water Interface ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Smooth Flow ◽  
Oil Water

In the petrochemical industry, multiphase flow, including oil–water two-phase stratified laminar flow, is more common and can be easily obtained through mathematical analysis. However, there is no mathematical, analytical model for the simulation of oil–water flow under turbulent flow. This paper introduces a two-dimensional (2D) numerical simulation method to investigate the pressure gradient, flow field, and oil–water interface height of a pipeline cross-section of horizontal tube in an oil–water stratified smooth flow, which has field information of a pipeline cross-section compared with a one-dimensional (1D) simulation and avoids the significant calculation required to conduct a three-dimensional (3D) simulation. Three Reynolds average N–S equation models (k−ε, k−ω, SST k−ω) are used to simulate oil–water stratified smooth flow according to the finite volume method. The pressure gradient and oil–water interface height can be computed according to the given volume flow rate using the iteration method. The predicted data of oil–water interface height and velocity profile by the model fit well with some available experiment data, except that there is a large error in pressure gradient. The SST k−ω turbulence model has higher accuracy and is more suitable for simulating oil–water two-phase stratified flow in a horizontal pipe.

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