Investigation of Paraffin Deposition During Multiphase Flow in Pipelines and Wellbores—Part 2: Modeling

2001 ◽  
Vol 123 (2) ◽  
pp. 150-157 ◽  
Author(s):  
Mandar S. Apte ◽  
Ahmadbazlee Matzain ◽  
Hong-Quan Zhang ◽  
Michael Volk ◽  
James P. Brill ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Multiphase Flow ◽  
Molecular Diffusion ◽  
Diffusion Theory ◽  
Wax Deposition ◽  
Flow Energy ◽  
Multiphase Fluid Flow ◽  
Multiphase Fluid ◽  
The University ◽  
Solid Liquid

A Joint Industry Project to investigate paraffin deposition in multiphase flowlines and wellbores was initiated at The University of Tulsa in May 1995. As part of this JIP, a computer program, based on the molecular diffusion theory, was developed for prediction of wax deposition during multiphase flow in pipelines and wellbores. The program is modular in structure and assumes a steady-state, one-dimensional flow, energy conservation principle. This paper will describe the simulator developed for predicting paraffin deposition during multiphase flow that includes coupling of multiphase fluid flow, solid-liquid-vapor thermodynamics, multiphase heat transfer, and flow pattern-dependent paraffin deposition. Predictions of the simulator are compared and tuned to the experimental data by adjusting the film heat transfer and diffusion coefficients and the thermal conductivity of the wax deposit.

Conjugate Heat Transfer and Effects of Interfacial Heat Flux During the Solidification Process of Continuous Castings

2003 ◽  
Vol 125 (2) ◽  
pp. 339-348 ◽  
Author(s):  
M. Ruhul Amin ◽  
Nikhil L. Gawas
Keyword(s):  
Heat Transfer ◽  
Continuous Casting ◽  
Cooling Rate ◽  
Solidification Process ◽  
Air Gap ◽  
Gap Formation ◽  
Continuous Casting Mold ◽  
Withdrawal Velocity ◽  
Multiphase Fluid Flow ◽  
Multiphase Fluid

Multiphase fluid flow involving solidification is common in many industrial processes such as extrusion, continuous casting, drawing, etc. The present study concentrates on the study of air gap formation due to metal shrinkage on the interfacial heat transfer of a continuous casting mold. Enthalpy method was employed to model the solidification of continuously moving metal. The effect of basic process parameters mainly superheat, withdrawal velocity, mold cooling rate and the post mold cooling rate on the heat transfer was studied. The results of cases run with air gap formation were also compared with those without air gap formation to understand the phenomenon comprehensively. The current study shows that there exists a limiting value of Pe above which the effect of air gap formation on the overall heat transfer is negligible.

Investigation of Thermal Effects on Gas-Oil Stratified Flow Wax Deposition

2020 ◽  
Author(s):  
Yuandao Chi ◽  
Nagu Daraboina ◽  
Cem Sarica
Keyword(s):  
Heat Transfer ◽  
Shear Stress ◽  
Temperature Gradient ◽  
Multiphase Flow ◽  
Local Heat Transfer ◽  
Stratified Flow ◽  
Local Heat ◽  
Gas Oil ◽  
Wax Deposition ◽  
Two Phase

Abstract Two-phase flow wax deposition is a flow-pattern-dependent phenomenon. The thickness and hardness of the deposit vary along the pipe circumference. In this work, two-phase gas-oil stratified flow wax deposition experiments at various liquid and gas flow rates have been conducted systematically using Garden Banks condensate and natural gas in a 2-inch I.D. multiphase flow loop under the pressure of 350 psi. Both deposit mass and wax content increased as superficial gas and liquid velocities increased. The local deposits were observed to be thinner but harder at the sides compared to the bottom of the pipe. Meanwhile, the cross-sectional deposits were crescent-shaped with an increasing local wax mass flux along the circumferential direction. The local multiphase hydrodynamic and heat transfer characteristics are known to play an essential role in the wax deposition process, and the temperature gradient is critical for establishing the concentration gradient. Thus, it is paramount to have a proper understanding of the local momentum and heat transfer to predict wax deposition in multiphase flow accurately. Therefore, numerical simulations with an SST (Shear Stress Transport) k∼ω turbulent model was implemented to understand local heat transfer in two-phase gas-oil stratified flow. After each simulation, the ANSYS CFD-Post was used to export, visualize, and analyze the simulated results. A total of 19 locations were selected for circumferential sampling to analyze the local heat transfer in the model. Detailed information on liquid volume fraction, shear stress, and temperature were analyzed. It has been observed that the local shear stress, temperature gradient, and inner wall temperature decrease with increasing θ. The thickness of the thermal boundary layer increases as θ increases due to reduced Nuθ. The comparison between the localized Nuθ and Nu from unified heat transfer model has revealed that variation in Nuθ is critical in the circumferential heat transfer calculation and wax deposition modeling.

scholarly journals Josef Stefan and His Contributions to Heat Transfer

2008 ◽  
Author(s):  
John Crepeau
Keyword(s):  
Heat Transfer ◽  
Moving Boundary ◽  
Radiation Heat Transfer ◽  
The Arctic ◽  
Arctic Seas ◽  
James Clerk Maxwell ◽  
Josef Stefan ◽  
The University ◽  
Solid Liquid ◽  
Boltzmann Law

Josef Stefan was a professor of physics at the University of Vienna between 1863 and 1893. During his time in Vienna he was a fruitful researcher in many scientific fields, but he is best known for his work in heat transfer. He was a gifted experimentalist and theoretician who made contributions to conduction, convection and radiation heat transfer. Stefan was the first to accurately measure the thermal conductivity of gases, using a device he invented called the diathermometer. He also determined the diffusion of two gases into each other, a process now known as Maxwell-Stefan diffusion. His work provided experimental verification of the newly formulated kinetic theory of gases published by the great Scottish physicist James Clerk Maxwell. Stefan also experimentally studied the motion of gases induced by evaporation along a liquid surface, a phenomenon known as Stefan flow. In addition, Stefan received data from various expeditions on ice formation in the arctic seas. From that solid/liquid phase change data, he formulated solutions to the moving boundary problem, now called the Stefan problem. The work for which he is most famous is the T4 radiation law which he deduced from the experimental work of a number of investigators. However, his theory was not widely accepted until his former student, Ludwig Boltzmann, derived the same relation from first principles. In their honor, the T4 radiation equation is called the Stefan-Boltzmann law. Despite his varied contributions, little is known about Stefan the man. This paper gives some details on his life and describes the seminal work he performed in broad areas of heat transfer.

scholarly journals Pressure Drop Determination for Multiphase Flow in a Vertical Well Tubing

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Sarah A Akintola
Keyword(s):  
Pressure Drop ◽  
Multiphase Flow ◽  
Flow Model ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Gas Industry ◽  
Modified Model ◽  
Multiphase Fluid Flow ◽  
Fluid Properties ◽  
Multiphase Fluid

Several studies have been carried out, by researchers to predict multiphase flow pressure drop in the oil and gas industry, but yet there seems to be one being generally acceptable for accurate prediction of pressure drop. This is as a result of some constraints in each of these models, which makes the pressure drop predicted by the model far from accurate when compared to measured data from the field. This study is aimed at developing a multiphase fluid flow model in a vertical tubing using the Duns and Ros flow model. Data from six wells were utilized in this study and results obtained from the Modified model compared with that of Duns and Ros model along other models. From the result, it was observed that the newly developed model (Modified Duns and Ros Model) gives more accurate result with a R-squared value of 0.9936 over the other models. The Modified model however, is limited by the choice of correlations used in the computation of fluid properties.

scholarly journals An extension of the multiple marker algorithm for study of phase separation problems at the mesoscale

2021 ◽  
Vol 347 ◽  
pp. 00025
Author(s):  
Quinn G. Reynolds ◽  
Oliver F. Oxtoby ◽  
Markus W. Erwee ◽  
Pieter J.A. Bezuidenhout
Keyword(s):  
Multiphase Flow ◽  
Immiscible Liquids ◽  
Performance Benchmarking ◽  
Flow Problems ◽  
Interfacial Surface ◽  
Multiphase Fluid Flow ◽  
Multiphase Fluid ◽  
Volume Of Fluids ◽  
Small Bubbles ◽  
Desirable Effect

Multiphase fluid flow is an active field of research in numerous branches of science and technology. An interesting subset of multiphase flow problems involves the dispersion of one phase into another in the form of many small bubbles or droplets, and their subsequent separation back into bulk phases after this has occurred. Phase dispersion may be a desirable effect, for example in the production of emulsions of otherwise immiscible liquids or to increase interfacial surface area for chemical reactions, or an undesirable one, for example in the intermixing of waste and product phases during processing or the generation of foams preventing gas-liquid decoupling. The present paper describes a computational fluid dynamics method based on the multiple marker front-capturing algorithm – itself an extension of the volume-of-fluids method for multiphase flow – which is capable of scaling to mesoscale systems involving thousands of droplets or bubbles. The method includes sub-grid models for solution of the Reynolds equation to account for thin film dynamics and rupture. The method is demonstrated with an implementation in the OpenFOAM® computational mechanics framework. Comparisons against empirical data are presented, together with a performance benchmarking study and example applications.

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