Dear Timo,
I cannot thank you enough for all your help and guidance. I wrote the
pointsource function as shown below. could you please let me know if it
is OK now or not ? I used 3 pointsources to represent each of the
production well and the injection well because I wanted to represent
fully penetrating wells.
void addPointSources(std::vector<PointSource>& pointSources) const
{
const auto enthalpy = IapwsH2O::liquidEnthalpy(293, 13.0e5);
const Scalar energyFlow = 1.93 * enthalpy; // 0.8 Kg/s *
enthalpy J/Kg
// The injection well (source term)
pointSources.push_back(PointSource({35, 45, 15}, {1.93,
energyFlow}));
pointSources.push_back(PointSource({35, 45, 25}, {1.93,
energyFlow}));
pointSources.push_back(PointSource({35, 45, 35}, {1.93,
energyFlow}));
// The production well (sink term)
pointSources.push_back(PointSource({65, 45, 15}, {-1.93,
0}));
pointSources.push_back(PointSource({65, 45, 25}, {-1.93,
0}));
pointSources.push_back(PointSource({65, 45, 35}, {-1.93,
0}));
}
However, the results I'm getting on paraview are a bit confusing to me
because I imposed Dirichlet boundary conditions to all boundaries which
are basically pressure and temperature gradients and they are the same
as the initial conditions
PrimaryVariables dirichletAtPos(const GlobalPosition &globalPos) const
{
return initialAtPos(globalPos);
}
PrimaryVariables initialAtPos(const GlobalPosition &globalPos) const
{
PrimaryVariables values(0.0);
Scalar densityW = 990; // Kg/m^3
Scalar depth = this->gridGeometry().bBoxMax()[2] -
globalPos[2];
// Hydrostatic Pressure
values[pressureIdx] = 11.0e5 -
densityW*this->spatialParams().gravity(globalPos)[2]*depth; //Pascal
// Geothermal Gradient
values[temperatureIdx] = 358.0 + depth*0.03; //Kelvin
return values;
}
However I could see what looks like numerical errors affecting certain
spots of the pressure boundaries (the low permeability layers on top and
bottom) (picture attached) and I also could see high temperatures (400+
Kelvin) in the production well while the highest temperature initially
is around 359.5 Kelvin (50 m thick domain) (picture attached). I would
really appreciate it if you could let me know if there's something wrong
here. Another thing causing confusion is that the simulation proceeds
really quickly and when I impose a mass rate of 0.38 Kg/s for each of
the 3 pointsources of a well which is equivalent to 100 m^3/day for the
well, it's like I am not injecting anything at all so I had to impose
higher mass rates !
PS: I used "using IapwsH2O = Components::H2O<Scalar>;" and
"const auto enthalpy = IapwsH2O::liquidEnthalpy(293, 13.0e5);"
because when I tried
"using FluidSystem = GetPropType<TypeTag, Properties::FluidSystem>;"
"const auto enthalpy = FluidSystem::liquidEnthalpy(293, 13.0e5);" it
gave me this error:
error: ‘liquidEnthalpy’ is not a member of
‘Dumux::OnePNIProblem<Dumux::Properties::TTag::OnePNICCMpfa>::FluidSystem’
{aka ‘Dumux::FluidSystems::OnePLiquid<double,
Dumux::Components::H2O<double> >’}
239 | const auto enthalpy =
FluidSystem::liquidEnthalpy(293, 13.0e5);
Thanks again Timo for your help !
Best Regards,
Mahmoud Atef
-------------------------------------------------------------------------------------------------
Il 2021-04-08 15:47 Timo Koch ha scritto:
On 8. Apr 2021, at 13:42, Mahmoud Atef Mahmoud Mohamed Aboelseoud
S277151 <[email protected]> wrote:
Dear Timo,
Thanks a lot for your reply. I didn't use the pointSources because I
didn't know how to assign the temperature inside such function for the
injection well because I want to impose a rate and also a temperature.
Hi Mahmoud,
for the pointSource for the OnePNI model you need to specify mass
(kg/s) and energy source (J/s) (Indices::conti0EqIdx (=0) and
Indices::energyEqIdx (=1)).
“NumEqVector" has size 2 because you have two equations.
The energy flow can be computed as massFlow*enthalpy(p,T) (neglecting
heat conduction which is usually unimportant here). So the temperature
enters via the enthalpy.
You can evaluate the correct enthalpy for your fluid system with
using FluidSystem = GetPropType<TypeTag, Properties:: FluidSystem>;
const auto enthalpy = FluidSystem::liquidEnthalpy(T, p);
for a temperature T (in K) and pressure p (in Pa).
In your examples below you build a temporary object of type FluidState
and set the temperature on this object. However this fluid state
object is used nowhere, so it does nothing.
Consequently you seem to inject mass without accounting for the energy
the injected fluid carries.
Hope this helps
Timo
I'm using the OnePNI model in my problem. I will try to be more
specific this time as I'm afraid I could be making some mistake that
I'm not aware of. To define both the injection and production wells
inside the sourceAtPos function, I'm writing the following:
NumEqVector sourceAtPos(const GlobalPosition& globalPos) const
{
NumEqVector values;
using FluidState = GetPropType<TypeTag,
Properties::FluidState>;
FluidState fs;
// we define one source term and one sink term
//Injection well (Source Term)
if ((globalPos[2] > 15 - eps_ && globalPos[2] < 35 + eps_) &&
(globalPos[1] > 45 - eps_ && globalPos[1] < 45 + eps_) &&
(globalPos[0] > 35 - eps_ && globalPos[0] < 35 + eps_))
{
fs.setTemperature(293);
values[contiWEqIdx] = 1e-1; // kg/(s*m^3)
}
//Production well (Sink Term)
else if ((globalPos[2] > 15 - eps_ && globalPos[2] < 35 + eps_)
&& (globalPos[1] > 45 - eps_ && globalPos[1] < 45 + eps_) &&
(globalPos[0] > 65 - eps_ && globalPos[0] < 65 + eps_))
{
values[contiWEqIdx] = -1e-1; // kg/(s*m^3)
}
else {
values[contiWEqIdx]=0;
}
return values;
}
where contiWEqIdx is defined in an enum as contiWEqIdx =
Indices::conti0EqIdx
and my model dimensions and cells are as follows:
[Grid]
Positions0 = 0 10 30 70 90 100
Positions1 = 0 10 30 70 90 100
Positions2 = 0 10 40 50
Cells0 = 1 2 4 2 1
Cells1 = 1 2 4 2 1
Cells2 = 1 3 1
where there are upper and lower boundary layers with very low
permeability (order of e-25 m^2) each 10 m thick. I'm not using any
refinement for the moment around the wells. Is there anything wrong
I'm making here in the above function and which causes me to have a
very limited range of mass rate below which the simulation proceeds
very quickly and above which I have really high pressures and the
simulator aborts ??!
In fact I want to impose a rate of 100 m^3/day in each well as it is a
common liquid rate and that's why I do the calculations mentioned in
the previous e-mail. but in order to implement what you proposed Timo
in your response which is using "elemVolVars[scv].density(phaseIdx)"
for the density and "scv.volume()" for the volume, shouldn't I divide
the volumetric rate of the well which is 100 m^3/day by (3 cells x 8
scv) before dividing by the volume and multiplying by the density ?
Anyway, I tried to follow what you proposed by writing the following
for the injection well for example
NumEqVector sourceAtPos(const GlobalPosition& globalPos) const
{
SubControlVolume scv;
ElementVolumeVariables elemVolVars;
NumEqVector values;
using FluidState = GetPropType<TypeTag,
Properties::FluidState>;
FluidState fs;
// we define one source term and one sink term
//Injection well (Source Term)
if ((globalPos[2] > 15 - eps_ && globalPos[2] < 35 + eps_) &&
(globalPos[1] > 45 - eps_ && globalPos[1] < 45 + eps_) &&
(globalPos[0] > 35 - eps_ && globalPos[0] < 35 + eps_))
{
fs.setTemperature(293);
values[contiWEqIdx] =
(1.157e-3*elemVolVars[scv].density(LiquidIdx))/(24*scv.volume()); //
kg/(s*m^3)
}
where LiquidIdx is defined in an enum as LiquidIdx =
FluidSystem::comp0Idx
but I'm getting the following error:
/home/mahmoud/dumux/dumux/dumux/discretization/cellcentered/mpfa/elementvolumevariables.hh:288:7:
note: candidate expects 1 argument, 0 provided
I would really appreciate it if you let me know how to correctly
accurate for the 100 m^3/day volumetric rate either using the
sourceAtPos function with elaborating the mistakes or using the
pointSource function showing how to impose the 293 kelvin temperature
for the injection well.
I'm extremely sorry for the long e-mail. I just wanted to clarify my
problem a bit more. Thanks in advance !
Best Regards,
Mahmoud Atef
------------------------------------------------------------------------------------------------
Il 2021-04-07 20:27 Timo Koch ha scritto:
Dear Mahmoud,
what you are doing seems correct to me. You can get the relevant cell
volume with “scv.volume()” so you don’t have to compute that
yourself.
You can also get the density with
"elemVolVars[scv].density(phaseIdx)". But that shouldn’t change
anything if you already used the correct volume in your computation.
You can also use pointSources (see e.g
https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/blob/master/test/porousmediumflow/1p/pointsources/timeindependent/problem.hh)
which is simpler for the case you describe.
There you just specify the position of the well(s) and the rate(s)
(this time directly in kg/s without the need for considering cell
volumes (that will be done automatically)).
I guess you have to recheck your scenario to see if you would expect
an influence on pressure for the specified production rate.
Best wishes
Timo
On 6. Apr 2021, at 18:05, Mahmoud Atef Mahmoud Mohamed Aboelseoud
S277151 <[email protected]> wrote:
Hello Dumux team,
I'm defining two wells inside a structured 3D Yasp grid, one is
injection and the other is production and I'm using the MPFA
discretization. The system is a geothermal system for which I'm
defining a certain low temperature for injection. I'm defining both
wells inside the sourceAtPos method and they are both defined inside
3 cells in the z direction. each cell is 10x10x10 m^3 Now I
understood from the doxygen documentation that the unit inside that
source function is Kg/(m^3.s) and I want to impose a rate of 100
m^3/day == 1.157e-3 m^3/s in each well so I'm dividing by (3 x 1000)
and then multiplying by 1000 kg/m^3 for water to get an estimation
of the mass rate to use so I get a value around 4e-4 Kg/(m^3.s) to
use. However whenever I use that value, the simulation proceeds
really quickly like I'm not injecting or producing anything at all
(static condition) and whenever I use a random higher mass rate like
0.1 for example, I get very high pressures and warnings during the
simulation and the simulator aborts. Could somebody please let me
know how to correctly account for the 100 m^3/day that I want to
impose in each of the production and injection wells ? tried using
some middle values and the simulation proceeded successfully but I
don't know the basis. Your guidance is much appreciated.
Best Regards,
Mahmoud Atef
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