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# Transport in Porous Media - Science topic

Explore the latest questions and answers in Transport in Porous Media, and find Transport in Porous Media experts.

Questions related to Transport in Porous Media

Hello,

I would like to know how to simulate water diffusion through a porous region using Ansys Fluent. Specifically, I am interested in simulating the following problem:

There is a pipe with insulation covering exposed to atmospheric conditions. Due to the condensation of water vapour at the outer surface of the insulation, water is deposited there. The water then diffuses through the porous insulation layer and reaches the outside of the pipe (inside the insulation). A constant temperature is applied inside the pipe. I would like to know the water content present at the outer surface (inside the insulation) of the pipe.

I am also interested in knowing what kind of inlet boundary needs to be applied.

I understand that this type of simulation is possible with WUFI software, but I believe it is limited to 2D geometry. Therefore, I am interested in how to solve this problem using Ansys Fluent software.

Thank you.

Hi,

I am trying to model heat and mass transfer in three phases (soil, water & air) porous media. I want to know what equation should I use for the mass transfer rate or mass flux (between water phase and air phase) due to the evaporation of water or condensation of vapors in porous media voids.

In Comsol software, we use the two physics

**"Heat Transfer in Porous Media"**and**"Heat Transfer in Solids and Fluids"**to study the heat transfer from a**porous**part to**solid and fluid**areas. The problem is that the interface between the porous and fluid or solid areas in both physics is defined as thermal insulation. How do we define these common areas boundary conditions to establish the heat transfer between the porous and solid or fluid areas? In some numerical studies, they used the**heat flux**boundary conditions for the common areas of the porous and fluid sections. Still, I do not think this boundary condition is appropriate.I am trying to simulate the heat transfer and fluid flow in a volumetric (porous) solar receiver in COMSOL Multiphysics. I know the material porosity, PPI and thermo-physical properties, however, the exact structural properties, i.e., pore size, solid wall thickness, pore shape, etc., are unknown.

Will it be correct to simulate the computational model as a single domain with given porosity instead of considering the detailed internal structure of the material?

If there is any research article where a similar procedure is adopted, kindly share it with me. I will be thankful to you.

Thanking you

------

Manoj Kumar Sharma

I'm currently doing simulations related with contact against porous materials (Tissues) in ABAQUS. As long as I use Pore Pressure=0 as Boundary Condition everything works fine and I'm able to obtain results. The issue is that in the contact area it will be fluid flow out of the material(exudation) due to the compression imposed. The fluid flow is in both contacting zones wich violates the continuity equation.

I've worked with the FLOW subroutine in order to control the boundary conditions in the contact area, and I also have tried the *Contact permeability keyword. I even tried to impose Pore Pressure=0 as an INITIAL boundary conditions.

I have also altered the parameters used to control the solutions (As the maximum number of cutbaks) .

I've read in many places in the ABAQUS MANUAL that by default ABAQUS imposed a sealed boundary condition. I guess this might be true for free contact surfaces but in my case it the program won't run if this BC are not imposed.

Nothing of what I've tried works, the program stops without calculating the very first time increment in all previous cases. Only if I forced the Pore pressure = 0 during the whole simulation, the problem works.

Any advice?

Thanks!

Any suggestions on analytical and numerical solutions? Any available codes to solve Mathieu equation available other than in math work websites ?

Dear all;

I am trying to simulate non-Newtonian fluid flow in porous media with the help of Palabos software. Palabos is a C+++ open-source library that solves flow problems with the lattice Boltzmann method. I am not familiar with object-oriented programming and I want to extract a value from a template that is used in every iteration. To be more precise; I want to print Omega (which is an (Nx-1)*(Ny-1) dimensional matrix) in every 250 iterations in the form of gif or data to validate my result. I added pcout to print variable in this function and it works but it is repeated every iteration which generates too much data ( imagine 200*200 lattice and 10000 iterations!).

I will be really glad if you could help me through this. the code is provided below. also, I uploaded

.h and .hh file to this message

Many thanks;

Elahe;

template<typename T, template<typename U> class Descriptor,int N>

T CarreauDynamics<T,Descriptor,N>::

getOmegaFromPiAndRhoBar(Array<T,SymmetricTensor<T,Descriptor>::n> const& PiNeq, T rhoBar) const

{

T nu0_nuInfoverCs2 = (global::CarreauParameters().getNu0()-global::CarreauParameters().getNuInf())*Descriptor<T>::invCs2;

T nuInfoverCs2 = global::CarreauParameters().getNuInf()*Descriptor<T>::invCs2;

T nMinusOneOverTwo = (global::CarreauParameters().getExponent() - (T)1)/(T)2;

T lambdaOverCs2sqr = global::CarreauParameters().getLambda()*Descriptor<T>::invCs2;

lambdaOverCs2sqr *= lambdaOverCs2sqr;

T piNeqNormSqr = SymmetricTensor<T,Descriptor>::tensorNormSqr(PiNeq);

T alpha = lambdaOverCs2sqr * piNeqNormSqr *(T)0.5

*Descriptor<T>::invRho(rhoBar)*Descriptor<T>::invRho(rhoBar);

T omega = carreauDynamicsTemplates<T,N>::fromPiAndRhoToOmega(alpha, nu0_nuInfoverCs2, nuInfoverCs2, nMinusOneOverTwo, this->getOmega());

T tau=(T)1/ omega;

T visco=((T)2 * tau - (T)1)/(T)6;

pcout << "" << visco << std::endl;

return omega;

}

I am looking into the permeation of gases through porous metallic sintered plates when different pressures are applied on either sides of the plate. Darcy's permeabilities and Forchheimer's constants of the plates are known. My aim is to predict the flow through such plates depending on the pressure differences.

I have found a model where the Darcy-Forchheimer-Equation is integrated into the Navier-Stokes-equations, and simple block meshing and finite volumes are very suitable for the prediction of throughput through the plates (at least in my opinion). However, the Darcy-Forchheimer-equation in Navier-Stokes is a velocity dependent source term and the experiments are quite similar to shock-tubes (High-Pressure on one side, low pressure on the other and inside the sintered plate as initial condition).

I wrote a simple simulation in Python which did not work. I think the reason for this is that energy conservation is broken because of the velocity dependence of the source term and the shock-type initial condition. Do you have any idea where I can find references / computer codes (Fortran, Matlab, Python) which would help me with my problem?

I'm using ANSYS Fluent 2019 with Space claim, my problem is involving moisture diffusion (therefore using Species transport). I found that my h2o can never pass through the porous zone.

I have tried varous porosity value, viscous resistance, with and without UDF of different diffusivity, and even (in space claim): shared topology or without shared topology but with contact. Do anyone know how to fix this?

Hello friends,

I intend to simulate the cementation process in porous media (i.e. granular soil). I'm not sure if I can model the cement slurry as a mere fluid with high viscosity and density. If it is possible, does it act as a Newtonian fluid or as a non-Newtonian one? If the slurry cannot be accurately modeled as a fluid, how can one simulate the flow of cement slurry/paste in a porous medium?

Any suggestion is appreciated. Thanks a lot in advance.

Fluid flow in porous media depends on shear rate and shear stress. The effective viscosity of the fluid can be determined using Darcy's law. We know that shear rate and shear stress varies along radial direction during the flow of fluid in a pipe. Do we have any similar method to determine the variation of shear rate and shear stress in porous media?

Dear All,

Any one knows how to model a 1D Advection Diffusion example on abaqus.

Regards,

Ahmad

Dear all,

I want to compare differences in the drainage capillary pressure curves for different simulations with experimental data. I want to show how close or far I am from the experimental data. What would be the most elegant solution? The orange line is the capillary pressure from experimental data.

Thank you in advance!

Best,

Alex

I want to find the analytical solution of a radial diffusion system (1D cylindrical coordinates). Here what is considered is pressure diffusion. The conditions are simple and similar to the following.

Initial P = P0

P(r=infinite) = P0

P (r= 0) = P1 when t > 0

I need the solution of P at any r_i and t.

The flow rate term is unknown.

Could anyone give any suggestion? Thank you.

- Dear all,
- I am trying to understand the data I collected when flowing water through a matrix of agarose gel (2% w/v) encapsulated in a tube giving a matrix dimensions of 2 mm in diameter and 20 mm in length. This agarose matrix is attached through the tube to a syringe pump working at flowrates in the range of ul/hr
- From my understanding, given this flowrate, this flow regime is truly dominated by viscous forces and should be described by Darcy's Law and Kozeny-Carman Equation. However, as you can see in the graphs, once pressure reaches a stable point, it starts oscillating.
- My question then is, does anybody understand why these oscillations happen and how can be explain them? I assume since Darcy's law draws a linear relation between Pressure Gradient and velocity using the permeability parameter, that these permeability is the one changing and affecting P. However, I have not yet found an answer in literature
- Thank you in advance

hello everyone,

I need your help. I was meshing a porous media geometry with ICEM, and after meshing, I wanted to transfer the data to #fluent, I encountered this error "WARNING: Mesh has uncovered edges. ANSYS Fluent needs a complete boundary (lines in 2D) or it will give a variety of errors and not read in the mesh! If this was 2D Hexa, perhaps your edges are not associated with perimeter curves".

What should I do, please help me?

P.S. in the attachment I'll upload an image of the geometry.

I have been trying to model the electrical double layer for geopolymer. But, I could not get any equations or simulation pathways that would help me calculate charge available at the surface of the materials.

Can you help me on this?

I conducted experiments of adsorption/desorption of a mixture of compounds on macro porous resin in fixed-bed continuous-flow and I calculated the experimental and the theoretical stoichiometric times. What is the meaning of the stoichiometric time? it refers to what exactly?

I am finding some conflicting literature on flow properties of metal foam/porous media. While some text books consider it as property of the porous media, some literature suggest that it vary with fluid.

1. Work of Dyga et al. - experimental determination of flow properties with air, water and oil - about 30% deviation in permeability (open access link : )

2. Word of Bodla et al. - microtomography based study - with air and water, up to 17% deviation in form drag coefficient, up to 2% variation in permeability (link :

- )

3. Work of Wilson et al. - //Permeability and form coefficient are two main hydraulic properties that characterize any porous medium. Once determined, they are global parameters, i.e., valid for the entire porous medium. Under isothermal conditions, they are independent of the properties and flow conditions of the fluid flowing through the porous medium.// (link: )

What is the correct approach?

Hello!

I would like to understand in what cases blood or some other biological liquid passes through implant or graft with some porous microstructure according the Darcy law (thanks to the pressure differences).

I have an idea to produce a research about blood permeability through various implants microstructure, but unfortunately it is harder than I thought to found some justification in literature that blood actually could pass through such microstructure due the Darcy law. Thus, I would be grateful for your help in this question - maybe you have some papers about it or some other helpful stuff.

Sincerely, Catherine

For a 3D single phase turbulent Air flow inside a partially filled channel with porous material,

**what kind of interface treatment does ANSYS Fluent use for the interface between a porous and a fluid zone by default?**I know there are d

**ifferent interface conditions**such as**,***The Ene, Levy and Sanchez-Palencia interface***, but i want to know which interface conditions does ANSYS Fluent use.***The Beavers-Joseph interface* For the porous zone

**Forchheimer extended Darcy’s equation**and the**thermal equilibrium model**have been employed and the flow has been considered as**laminar flow**, but for the fluid cell zone**the flow is turbulent**and**RNG k-Epsilon turbulence modeling**has been utilized.Could anyone tell me how large usually the magitude of induced pore pressure changes during a well-drilling in an aquifer? In my case, it is a near 200 m deep well. Perhaps the induced pore pressure is related to the drilling mud? If possible, please give a reference. Thank you.

I have an unknown sample to characterize using different techniques (mainly pore size distribution):

-X-ray computed tomography

-Mercury intrusion porosimetry

-Gas porosimetry

-BET tests for the surface area.

how would you proceed to make a perfect analysis (taking into consideration the time/money/precision factor)?

Any explanation, recommendation and/or articles for comparative studies would be a perfect help. Thank you in advance.

Moustafa

Could anyone tell me that where can I find an analytical solution of diffusion equation (PDE) with 1D zero flux boundary at outlet? I need this for calculating rock permeability from pressure diffusion.

I have found there are some literatures giving solution in a semi-inifinite domain. What I want to get is an analytical solution in a finite domain with at x=0, c =C0 and at x =L, flux = 0.

Thank you.

I need to simulate the transition of Flow through Coarse Porous Media such as Rock-fill dams, to investigation of Water level profile in each distance from up-stream and determination of discharge of fluid seepage from the body of these media. Notice, I want to simulate a Single-Phase Flow.

How can I simulate this project? Please suggest and introduce a useful software for this issue to me...

What is your idea about Flow 3D, Fluent, ABAQUS,...

Conference Paper A numerical study of the flow through coarse and homogeneous...

Conference Paper Transition of Flow through Coarse Porous Media with Network ...

Hi,

I need to set a porous zone (as radiator) in fluent. But I dont know any about the inputs like viscous resistance or velocity resistance coefficients. For a panel radiator for example, how can I determine these factors. cooling air will go through the small sections(ducts) between the radiator panels.

Lets say I want a disc shaped porous medium with 3mm thickness and 15mm radius but with holes of a certain shape and size (lets say squares with 3mm2 area)

Possible?

Currently I'm actually modeling the porous region but I think using Porous media would be a better choice overall

Hello All,

I'm new to porous media simulations. I'm trying to create a pressure drop using porous media. I plotted the velocity vs dP/L and curved fitted using the equation Ax^2+Bx. I used A as inertial resistance and B as viscous resistance. My viscous resistance value is one order of magnitude less than the inertial resistance. Kindly let me know if this trend is acceptable, I heard from some that the viscous resistance should always be higher than the inertial resistance. I can provide more info if needed. Thank you.

**I am doing a column experiment in saturated porous media, using different P concentration effects on the transport of ferrihydrite colloids. I got a 5 ml effluent for every sample. I divided that in two parts. The 2.5 ml I used for measuring soluble P after centrifuge and filtration with 0.22 um filter membrane and measured via Murphy and riley method. while for TOTAL PHOSPHORUS, I took 1 ml of effluent and digested with 4 ml of 6M HCL for 24 hrs as per the digestion process for ferrihydrite colloids described in literature and then I used p-nitrophenol indicator (yellow indicator) and neutralized sample with 4M NaOH and 0.1 HCl. and then after neutralizing the sample I measured total P with murphy and riley (1962) method. My question is that, Is that the right way of measuring total P? I got good results by the way but need opinion from experts...**

Dear community,

I am interested in modeling capillary forces in porous media using the VOF model. The reason for using VOF is mere because of stability. Eulerian-Eulerian is too sensible to IC and most of the case it just diverges or blows up.

I have reviewed the literature and I found two interesting papers, that shed some light on how to determine the capillarity pressure and force in a porous media based on the porosity and permeability. Interested readers refer to:

2.-

These two works made great work defining such parameters. However, when we are modeling extra terms in VOF, we need to include those as a volumetric source term (body force) at least in STARCCM+.

My question is how to cast that force that represents the net force on the pad when a "radius of equivalent capillary " is used to represent the porous media.

So far, I've failed at casting that term into a body force source term. One thing that needs to be check is that the sum of the gravity force (another body force) + the net capillary force must be positive. In my case, I still have a negative number, meaning that my capillarity force is not big enough to overcome gravity.

Any suggestion ??

Julio

I'm looking for codes that can do this for saturated and/or unsaturated porous media. I expect there are a few that can handle the porosity changes easily, but predicting permeability changes seems much more complicated.

**just to update the community and people interested in the problem.**

**I read that if and only if when one apply porous jump as the boundary condition, FLUENT would only consider flows perpendicular to the actual surface. That is definitely not our case. In particular, our system doesn’t possess inlet and/or outlet flows (or it doesn’t have to be perpendicular specifically), since it will be a real earth model simulation which will be representing fluid dynamics and it’s chemical interactions through 3-layered marine sediment. So, we are interested in natural flow of the water liquid in the undermost body, chemical interactions and outcomes of it in the middle body, once again natural flow of the water liquid and products from the reaction in the uppermost body by time, i.e. we solve the system as transient. As you can see, it’s not like a flow through cylindrical objects etc., thus it’s totally different. Today, we conclude that we need to figure out another option for boundary condition, since porous jump seems a bit non-functional.Once again the main fault we encounter when we run the program is most likely arised from enforcing a chemical reaction just in the middle body. Now, I am searching for some answers regarding how to enforce a chemical reaction just in a specific region(in our case in the middle) of a body.**

My system is composed of 3 bodies, and the middle body will be the host of a reaction. All those three systems have the porous zone option activated. I want the water liquid which flows through the undermost body and arriving the porous jump boundary, passing through this boundary, reacting with the chemicals I designated in the middle body, creating those other products, and finally once again those products for this time passing through the second porous jump boundary and reaching to the uppermost body.

I hope you could imagine the system. Now I created 2 cell zones just above these porous jump boundaries with a width of 1 grid cell which was 8 m for my case, and also set the Y velocities of those interior cell zones as 0. Logically, since they are just above the porous jump boundaries they are actually in-situ of the reaction area(the middle body). So, I did activate the porous zone and reaction options for my cell zones, and set '0' value for the Y velocities in the fixed values tab (A researcher who encountered the same problem proposed this method, so I wanted to give it a try.).

Now, as for porous jump boundaries, I still set them as porous jump boundaries which I believe where the problem arises. When I didn't create a namedselections for them in mesh section, ANSYS Fluent gives the error for example:

Error: Species are not solved in neighbor cell threads (14 and 16)\n of interior zone 6. \n

Error Object: #f

but when I set them as porous jump boundaries, this time it gives an error of segmentation fault, no flow detected at porous jump 7(exp.).

One more thing, the properties of the porous jump condition:

FACE PERMEABILITY: 1e+10(default) How do I set it, I have a mesh system of 5000x5000 m and 40000 elements(grids) in this system

POROUS MEDIUM THICKNESS: 0 it is.

PRESSURE-JUMP COEFFICIENT: 0(default) I saw some calculations for cylindirical studies but I don't know how to calculate it or what are the values for 2D planar structures(systems).

What is it that I'm doing completely wrong and/or fail to notice?

Any comment would be much appreciated. Thanks in advance.

Cheers,

Selvi

Hello all,

I am looking for applications or systems where two phases, wherein one is Newtonian while other is non-Newtonian of both are non-Newtonian are involved.

Some initial search do gives some broad fields like bio-medical, chemical process but I am looking for more precise examples.

It would be kind to seek some answers.

Thanks

I am modelling a flow through porous media using ANSYS Fluent. The flow through porous media is assumed to be laminar. Shall I need to check y+ value in the porous zone also?

Hey everyone,

I'm trying to simulate a porous media column that's initially saturated with water, and get's progresively filled with air from the top. For water to move, the driving force is gravity, but in COMSOL there's no possibility of applying either gravity or volume forces to a domain when using this physics package.

Is there a stablished way to implement gravity in this kind of model, either through weak contributions or any other method?

Thanks in advance!

Hello, I am trying to solve these PDE's (see the attached file) but I could not find the appropriate method to solve these equations. Can anyone suggest me which method of PDE is suitable to solve these equations?

Please guide me it will be highly appreciated.

Thank you.

I am doing a soil column experiment, using quartz sand as a transport medium. We are using 0.001 M NaNO3 as a background solution. Before injection to soil column the pH was adjusted to 7.5 with NaOH and HCl, but after sometime the pH of influent changes and the pH tends to decrease, so does the effluent. After this we used 0.0001 M NaHCO3 to stabilize the pH. The concentration of the influent becomes 0.0009 M NaNO3 + 0.0001M NaHCO3. but still it doesn't work and the pH of influent still tends to decrease. Please help me to solve this issue. I want to keep the pH at 7.5.

I am working on a project related to transport phenomenon in porous medium and I am required to calculate the saturation of the porous medium. Can I use the volumetric difference method to find out the saturation? Measuring the volume of fluid at inlet and outlet and then the difference in the volume is the amount of fluid trapped in the porous medium. Can I use this method?

Why does the imbibition process need a much higher pressure than the drainage process in the two-phase fluid flow in porous media?

Principally, because capillary pressure plays a positive role to drive the flow of wetting phase (e.g., water), the flow in an imbibition process (e.g., water displacing oil) should be easier (less pressure cost) than in a drainage (e.g., oil displacing water) process.

However, as shown by many laboratory core-scale test results, an imbibition usually needs a much higher pressure (e.g., 100 kPa) to drive the flow than a drainage (e.g., 20 kPa) under the same injection rate (e.g., 0.5 mL/min).

The high pressure during imbibition should be not due to the viscosity difference between fluids. When injecting either one of the phases alone in the media, the pressure drop is quite low.

Hi y'all,

I was trying to push water through a piece of porous media. I was measuring the pressure drop of it under a constant flow rate, and saw that the pressure drop kept increasing over time.

It starts as ~1 psi, and increases to like 10 psi after 7 minutes

Does anyone know why? This only happens to one type of my samples.

Edit: this is an experiment. It keeps increasing, but I can’t measure accurately because my tunings start to leak after 12 psi

Using a local thermal equilibrium model required that the averaged heat exchange between each phase of a porous medium is equal to zero. However, locally it could be very high. Effective conductivity will, thus depends on ratio of thermal conductivity and specific surface (exchange surface between each phases). It means that in a case of close thermal conductivity, the effective conductivity will not be the sum of separate phase effective thermal conductivity.

Hydrodesulfurization in packed beds takes place according to the following general reaction:

Sulfur Compound (ArS) + 2H2 --- H2S + Aromatic (Ar)

The kinetic rate is given by:

rHDS = (−KHDS) [ArS]^1.6 * [H2]^0.56 / (1+kad * [H2S]) [kmol/(kgs • s)]

The adsorption coefficient (kad = 50, 000 [m3/kmol]) does not depend on the temperature.

KHDS = 2.5•10^12 • exp(-19.384/Ta) [(m3)^2.16/(kg •(kmol)^1.16 • s)]

The geometry is a 3D cylinder and assembly meshing gives me a minimum orthogonal quality of 0.92, which is a desirable mesh. I have activated the Eulerian 2 phase and species transport models, and selected the mixture template for both the phases in the species transport model. Next in the materials section, all four materials (ArS, H2, Ar, and H2S) are defined inside the mixture template. The porous media is selected in the cell zone conditions and the appropriate UDF is loaded for the same.

Following this step I have attempted two different ways to execute the simulation:

1. Selecting mixture template for both gas and liquid phases and defining the materials in the same. Then, defining the reaction by defining the stoichiometric coefficients in the mixture template in the materials section. The following UDF for the reaction rate taken from the ANSYS manual was modified according to my reaction and defined and loaded as a function hook:

#include "udf.h"

#include "mem.h"

#define KHDS 0.005083992078

DEFINE_VR_RATE(vol_reac_rate,c,t,r,mole_weight,species_mf,rate,rr_t)

{

begin_c_loop(c,t)

{

real X_ars=C_YI(c,t,3)*C_R(c,t);

real X_h2=C_YI(c,t,1)*C_R(c,t);

real X_h2s=C_YI(c,t,0)*C_R(c,t);

if (FLUID_THREAD_P(t) && THREAD_VAR(t).fluid.porous)

*rate=((-KHDS)*(pow(X_ars,1.6))*(pow(X_h2,0.56)))/(1+(kad*X_h2s));

else

*rate = 0;

*rr_t = *rate;

}

end_c_loop(c,t)

}

2. Selecting two different templates to define the materials and following the remaining steps as it was in point no. 1.

I am using ANSYS Fluent for the simulations and maintaining a time step size of 1e-08, but there is no change in the mass fraction of the reactants. In other words the mass fractions of ArS and H2 are 1.0 throughout the simulation and mass fractions of Ar and H2S are 0.

Any kind of support regarding this would be reallyhelpful.

Thanks.

For a given porous medium with known porosity, particle size and other necessary material properties, how can I arrive at an equation which would express the time required for the given porous medium to fully saturate? The fluid properties and flow conditions (flow rate, pressure drop, etc.) are known. Can I express Darcy's equation as a time-dependent equation?

Dear Researchers,

I am now working on the development of modeling EOR project. However, I am stuck with the method to simulate

*flow diversion*mechanism created by polymer flood that reduce high permeability zone. The flow then will sweep into small permeability area.One solution I found was using

*Dynamic Permeability Model*. Which is not possible to be created in CMG or other reservoir simulation.Please I need your advise :)

Thanks

Madhan

**I need some literature about transport of Phosphorus in soil porous media.**

What are the steps required to solve numerically the phenomena of turbulent natural convection in porous media?

Sincerely, dear friends

Hi everybody,

Both of groundwater modeling system(GMS) and surface water modeling system(SMS) are well known.

Is it possible link them to evaluate flow exchange and pollution transport in river-aquifer interactions?

Which two software do you recommend for this purpose?

Thank you for even the slightest mention about this.

Azade

in the small diameters (or depth for rectangular one) the trickle flow can't be exist. am I right? what is the threshold?

The problem physics involves leakage past calibrated orifices of the piston , which is a moving boundary. In addition , the fluid is magnetisable, i.e MR Fluid .and its apparent viscosity can be varied in realtime. So the need is to model and solve for the behaviour in terms of Shear force developed or the apparent viscosity change with change in magnetisation,

Two-phase flow without the presence of porous media are traditionally solved by the Volume of Fluid (VOF)-like methods.

I would want to investigate some multiphase flow parameters (pressure gradient, liquid holdup among others) of some oil wells and compare them with results of some commercial software using the the various flow models - Beggs and Brill, Asari et al.,

I would like to analyse the heat transfer in the wells as well.

i would be grateful for matlab codes to help me with my analyses

hi, i am trying to understand why the porosity is included in several models of mass transfer in porous media and in other models is not included

I am looking for the following properties of Thermoplastic Elastomers or TPE like materials:

1.Flow resistivity (Pa.s/m^2)

2.Porosity

3.Tortuosity factor

Will also like to know from experts alternative ways to simulate the sound Transmission Loss of acoustic plugs made of TPEs.

Best Regards,

David

At present I'm having difficulties in making the solid particles flow inside the channel.

So can anyone give some inputs on this?

I have a coupled darcy flow and heat transfer in porous media module in COMSOL.

I would like to independently know the temperature of the fluid and temperature of the porous medium separately, however I see only one temperature. Does anyone know how to incorporate 2 temperatures?

The same has been raised in a COMSOL thread also.

Hello everybody,

I have a question in solving a fully developed porous tube. As we know, porous equations are under volume averaging in an r.e.v. So, because of using averaged amount of velocities, is it ok to consider axisymmetric boundary condition in the center of pipe?

thanks a lot.

Hello.

I am working on a micro scale simulation of evaporation inside a porous structure, using ANSYS FLUENT. It is a transient two phase model(VOF) considering water and vapor inside a micro scale pore. I am using UDF codes to apply the source terms relative to the mass transfer according to Schrage's model formulation.

The results that I get seem to be logical, but my problem is that the time steps that I have to use are very small ( in the order of ~1e-9 s), which make it impossible to reach convergence.

Every time I increase the time step, I face the error that the "Global Courant number is greater than 250.00. The velocity field is diverging. check the solution and reduce the time step".

I really appreciate it if you have any suggestions or solutions for this problem or you have any recommendations for me to increase the time steps to more realistic values.

What type of contacts do we need to use for interface between fluids and solid ?

(For Fluent)

hi every body i need your help to model a deform-able solid that amount of air trapped in it and then a force is applied on the boundary of solid ...

thanks

Recently i have been trying to solve such a problem: how to couple free flow and Darcy flow for two phase fluid by Comsol in other to simulate the real situation of fluid flow freely near the permeable wall. I tryed to simulate the free flow (between two planes or in a pipe, etc) by phase field model and Darcy flow by two phase Darcy model. In the interface of the two models, we have to set three conditions: (1)tangential stress by using Beavior-Joseph-Saffman(BJS) boundary condition; (2)equal pressure; (3)equal velocity field. We can add the BJS condition by correcting the weak expression of Inlet pressure, no viscous stress. But how to constrain the equal pressure and velocity? By weak constraint, too? And how to solve the coulpling models is another problem. I want to solve it segregatedly. First solve the phase field model with the pressure constraint in the interface to get all other parameters like velocity and phase field variale. Then use the velocity obtained as the interface condition of Darcy model and to solve Darcy model to get a new pressure. Then go back to the first step to get the solution of the next time step. I know segregated solver will be a good choice. But does it solve the problem as the above sequence? I don't understand this solver's real theory. Thanks a lot if anyone can help me! It has perplexed me so long.

Let us consider a periodic box filled with a fluid. There are solid fixed inclusions in the box. The Reynolds number is low and the Stokes equations apply. A space varying but time invariant volume force drives the fluid. What conditions must the volume force satisfy so that the flow rate across the box is zero in permanent regime ?

The routine and classical reservoir engineering divides the composite systems as either parallel, series, or a mix of both cases. In these systems, the overall systems permeability and porosity will be determined by writing the Darcy's law equation for each layer and equating either the flow rate (in series systems) or overall pressure drop (in parallel systems). However, this is not the case when the interface between layers is inclined or curved. An example is shown in the attached file.

I appreciate receiving any suggestion that helps calculating average porosity and permeability for this system.

I am a PhD candidate trying to use DE-LBM for modeling the behavior of a porous media (sandy soil for instance) subjected to fluid flow. I just started to understand the fundamentals of LBM. Is the LBM formulation independent of the coefficient of permeability (k)?

During a compaction of bitumen emulsion-based materials for pavement structural layers, and after it is finished, free water is released as a consequence of emulsion breaking. Thereafter, water steadily migrates through porous media of the specimen and evaporates outside specimen. Depending form the environmental conditions, this process takes place for weeks. I am looking for non-destructive methods to study the process of transport and evaporation of that water over time.

I am modeling Bubble array acting as impact reduction liners, where bubble contains fluid in it. So, I am using hydrostatic element inside the bubble. What should be the element type I should use to mesh the bubbles?

Thank you

I have CT images of metal foam and was able to import it to ICEM CFD as '.STL ' file and mesh the solid part.

I want to create a domain enclosing the solid part with void spaced occupied by fluid, for this I have separate solid and fluid part.

Even though currently I am able to identify solid part and name it as a single part, same is not possible with fluid domain.

How can I identify the void space as a part, so that subsequent meshing of these part could be done?

Dear researchers,

I am interested with the research of the simultaneous visualization and pressure-drop measurement of the two-phase flow in transparent channels. I am looking for cooperation with scientists who correlated gas-solids or gas-liquids flow imaging with different quantitative features, such as:

a) pressure drop values along the channel;

b) heat transfer values of the process;

c) the reaction speed value inside the channel;

d) etc...

I tried to simply illustrate the problem in the attached image.

I have developed interesting analytical methods for qualitative and quantitative correlation research on two-phase flow dynamics, and I am interested in cooperation.

Best regards.

Hi all,

I'm trying to define the parameters for ven Genuchten and Brooks Corey models to simulate immiscible flow in porous media but I'm don't know how to proceed exactly as I don't have a lot of knowledge in this particular field.

Actually, I'm intending to simulate immiscible fluids flow in porous media using Comsol Multiphysics and a model describing the variation of capillary pressure with saturation is needed.

Any guidance or idea ?! I will be very thankful.

Zahreddine.