Electrical impedance imaging for prediction of interfacial area density in two-phase flow

1993 ◽  
Author(s):  
O. C. Jones ◽  
M. K. Kiymik ◽  
H. R. Ozcalik ◽  
Jen T. Lin
Keyword(s):  
Electrical Impedance ◽  
Two Phase Flow ◽  
Interfacial Area ◽  
Phase Flow ◽  
Two Phase ◽  
Area Density ◽  
Electrical Impedance Imaging ◽  
Impedance Imaging ◽  
Interfacial Area Density

Numerical Investigation of Air-Oil Two-Phase Flow Pattern Transition in the Scavenge Line of an Aeroengine

2021 ◽  
Author(s):  
Ghofrane Sekrani ◽  
Jean-Sebastien Dick ◽  
Sébastien Poncet ◽  
Sravankumar Nallamothu
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Numerical Models ◽  
Interfacial Area ◽  
Sudden Expansion ◽  
Phase Flow ◽  
Two Phase ◽  
Ansys Fluent ◽  
Before And After ◽  
Interfacial Area Density

Abstract Since most research investments in aeroengines have been targeted at the hot and cold sections, the oil system has remained an area poorly understood. Optimum sizing of the oil system can directly reduce the engine’s weight and specific fuel consumption while maximizing service life. The understanding of air/oil interaction in scavenge lines is required to influence the design of the oil systems and achieve those objectives. The challenge is in the existence of numerous possible flow regimes and phase interactions. In scavenge lines, a complex two-phase flow results from the interaction of sealing airflow and lubrication oil. Scavenge lines can have bends, junctions and sudden area changes which complicates their modeling by amplifying pressure gradients and turbulence generation, and causing the flow to change morphology (annular, slug, stratified, bubbly, mist, etc.). Several multiphase flow approaches have been developed to model two-phase flow in straight scavenge lines. However, up until now, no methodology is preferred by the community for simulating two-phase flow in such application. There are still many unknowns regarding the modeling of turbulence, phase interaction and the compressibility of immiscible mixtures such as air and oil. The present study compares the performance of two numerical models: Volume of Fluid (VOF) and Algebraic Interfacial Area Density (AIAD), for simulating the air/oil flow in a suddenly expanding scavenge line against the experimental data of Ahmed et al. [1–2]. The AIAD model is a two-fluid Eulerian approach newly implemented on Ansys Fluent. Discrepancies between the two models for predicting pressure loss and void fraction are evaluated and discussed into details. The flow regime before and after the sudden expansion is identified using iso-surfaces of the void-fraction and compared against visual data. Based on the results presented, recommendations are formulated for further work regarding the calibration of AIAD modeling parameters.

A Physically Based, One-Dimensional Two-Fluid Model for Direct Contact Condensation of Steam Jets Submerged in Subcooled Water

2015 ◽  
Vol 1 (2) ◽  
Author(s):  
David Heinze ◽  
Thomas Schulenberg ◽  
Lars Behnke
Keyword(s):  
Direct Contact ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Interfacial Area ◽  
Phase Flow ◽  
Two Phase ◽  
One Dimensional ◽  
Two Fluid Model ◽  
Contact Condensation ◽  
Two Fluid

A simulation model for the direct contact condensation of steam in subcooled water is presented that allows determination of major parameters of the process, such as the jet penetration length. Entrainment of water by the steam jet is modeled based on the Kelvin–Helmholtz and Rayleigh–Taylor instability theories. Primary atomization due to acceleration of interfacial waves and secondary atomization due to aerodynamic forces account for the initial size of entrained droplets. The resulting steam-water two-phase flow is simulated based on a one-dimensional two-fluid model. An interfacial area transport equation is used to track changes of the interfacial area density due to droplet entrainment and steam condensation. Interfacial heat and mass transfer rates during condensation are calculated using the two-resistance model. The resulting two-phase flow equations constitute a system of ordinary differential equations, which is solved by means of the explicit Runge–Kutta–Fehlberg algorithm. The simulation results are in good qualitative agreement with published experimental data over a wide range of pool temperatures and mass flow rates.

Estimation of the fluid-fluid interfacial area using kinetic interface sensitive tracers in dynamic porous media experiments

2021 ◽  
Author(s):  
Alexandru Tatomir ◽  
Huhao Gao ◽  
Hiwa Abdullah ◽  
Martin Sauter
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Two Phase Flow ◽  
Organic Liquid ◽  
Column Experiment ◽  
Interfacial Area ◽  
Breakthrough Curves ◽  
Water Soluble ◽  
Phase Flow ◽  
Two Phase

<p>Fluid-fluid interfacial area (IFA) in a two-phase flow in porous media is an important parameter for many geoscientific applications involving mass- and energy-transfer processes between the fluid-phases. Schaffer et al. (2013) introduced a new category of reactive tracers termed kinetically interface sensitive (KIS) tracers, able to quantify the size of the fluid-fluid IFA. In our previous experiments (Tatomir et al., 2018) we have demonstrated the application of the KIS tracers in a highly-controlled column experiment filled with a well-characterized porous medium consisting of well-sorted, spherical glass beads.</p><p>In this work we investigate several types of glass-bead materials and natural sands to quantitatively characterize the influence of the porous-medium grain-, pore-size and texture on the mobile interfacial area between an organic liquid and water. The fluid-fluid interfacial area is determined by interpretation of the breakthrough curves (BTCs) of the reaction product of the KIS tracer. When the tracer which is dissolved in the non-wetting phase meets the water, an irreversible hydrolysis process begins leading to the formation of two water-soluble products. For the experiments we use a peristaltic pump and a high precision injection pump to control the injection rate of the organic liquid and tracer.</p><p>A Darcy-scale numerical model is used to simulate the immiscible displacement process coupled with the reactive tracer transport across the fluid-fluid interface. The results show that the current reactive transport model is not always capable to reproduce the breakthrough curves of tracer experiments and that a new theoretical framework may be required.</p><p>Investigations of the role of solid surface area of the grains show that the grain surface roughness has an important influence on the IFA. . Furthermore, a linear relationship between the mobile capillary associated IFA and the inverse mean grain diameter can be established. The results are compared with the data collected from literature measured with high resolution microtomography and partitioning tracer methods. The capillary associated IFA values are consistently smaller because KIS tracers measure the mobile part of the interface. Through this study the applicability range of the KIS tracers is considerably expanded and the confidence in the robustness of the method is improved.</p><p> </p><p> </p><p>Schaffer M, Maier F, Licha T, Sauter M (2013) A new generation of tracers for the characterization of interfacial areas during supercritical carbon dioxide injections into deep saline aquifers: Kinetic interface-sensitive tracers (KIS tracer). International Journal of Greenhouse Gas Control 14:200–208. https://doi.org/10.1016/j.ijggc.2013.01.020</p><p>Tatomir A, Vriendt KD, Zhou D, et al (2018) Kinetic Interface Sensitive Tracers: Experimental Validation in a Two-Phase Flow Column Experiment. A Proof of Concept. Water Resources Research 54:10,223-10,241. https://doi.org/10.1029/2018WR022621</p>

Modeling Two-Phase Flow in Porous Media Including Fluid-Fluid Interfacial Area

2008 ◽  
Author(s):  
Jennifer Niessner ◽  
S. Majid Hassanizadeh ◽  
Dustin Crandall
Keyword(s):  
Porous Media ◽  
Capillary Pressure ◽  
Two Phase Flow ◽  
Interfacial Area ◽  
Flow In Porous Media ◽  
Extended Model ◽  
Phase Flow ◽  
Two Phase ◽  
Specific Interfacial Area ◽  
Macro Scale

We present a new numerical model for macro-scale two-phase flow in porous media which is based on a physically consistent theory of multi-phase flow. The standard approach for modeling the flow of two fluid phases in a porous medium consists of a continuity equation for each phase, an extended form of Darcy’s law as well as constitutive relationships for relative permeability and capillary pressure. This approach is known to have a number of important shortcomings and, in particular, it does not account for the presence and role of fluid–fluid interfaces. An alternative is to use an extended model which is founded on thermodynamic principles and is physically consistent. In addition to the standard equations, the model uses a balance equation for specific interfacial area. The constitutive relationship for capillary pressure involves not only saturation, but also specific interfacial area. We show how parameters can be obtained for the alternative model using experimental data from a new kind of flow cell and present results of a numerical modeling study.

One-dimensional interfacial area transport for bubbly two-phase flow in vertical 5 × 5 rod bundle

2018 ◽  
Vol 72 ◽  
pp. 257-273 ◽  
Author(s):  
Hang Liu ◽  
Liang-ming Pan ◽  
Takashi Hibiki ◽  
Wen-xiong Zhou ◽  
Quan-yao Ren ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Interfacial Area ◽  
Phase Flow ◽  
Two Phase ◽  
Interfacial Area Transport ◽  
One Dimensional ◽  
Rod Bundle

MEASUREMENT OF INTERFACIAL AREA TRANSPORT OF GAS-LIQUID TWO-PHASE FLOW IN A MINI PIPE USING IMAGE-PROCESSING

2004 ◽  
Vol 2004.9 (0) ◽  
pp. 73-76
Author(s):  
Norihiro Fukamachi ◽  
Tatsuya Hazuku ◽  
Tomoji Takamasa ◽  
Takashi Hibiki ◽  
Mamoru Ishii
Keyword(s):  
Image Processing ◽  
Two Phase Flow ◽  
Interfacial Area ◽  
Phase Flow ◽  
Two Phase ◽  
Interfacial Area Transport
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