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- - flowRateProfile (https://www.cfd-online.com/Forums/openfoam-solving/149192-flowrateprofile.html)

I am using coalChemistryFoam.
1,In the patchInjection, there is a keyword "flowRateProfile", what doest it mean?
2, If massTotal is 0.001625, SOI=0, duration=0.5, so massFlowRate=massTotal/duration=0.00325, is it right?

Anyone can help me?Thank you.

Quote:

Originally Posted by musabai (Post 533702)

Hey have you solved ur problems?
I have the same question, what does flowRateProfile mean?

Quote:

Originally Posted by chpjz0391 (Post 599538)

Hey have you solved ur problems?
I have the same question, what does flowRateProfile mean?

I think it's just mass flow rate. Hope this is helpful.

I'm also working on a Lagrangian dispersion problem.

As far as I understand "FlowRateProfile" specifies the source mass flow rate as a function of time. See for example tutorial ./sprayFoam/aachenBomb/constant/sprayCloudProperites.

You could also specify a "sizeDistribution" for the individual particles.

Does anyone know of a good documentation source for the Lagrangian Cloud Properties file? I.e. an explanation of what options are and units of parameters?

Thanks,

Anders

Quote:

Originally Posted by musabai (Post 599651)

I think it's just mass flow rate. Hope this is helpful.

Thanks for your reply. Here I have some other questions,
1.after the simulation, do you know how to count the particles number in a specified area? do you have any hints?
2. do you simulate a steady state or transient state? In tutorial simpleReactingParcelFoam, patch is another inlet which inlet air with a certain velocity. can we just inject particles without airflow? If we can, how should we set the BD.

Sorry for my poor English. Hope you can understand.

Quote:

Originally Posted by fluidos (Post 599692)

Hi Anders, could you specify your request? what kind of lagrangian cloud properties file do you want? steady-state or transient or different injector?

By the way, do you know how to count the number of particles after simulation?

I'd like to do massless Lagrangian particles with stochastic dispersion for a steady state, simpleFoam problem (e.g. a RANS problem).

In principle if I have already computed the velocity field this should be a post processing computation. Do you know of any tutorials on how to do that?

Unfortunately I do not know of a good way to count particles. One suggestion is that you could export the position of each particle for the timestep of interest and write a Python or Matlab script to search and count in the 3D subdomain.

Regards,

Anders

coal combustion with openfoam

Quote:

Originally Posted by musabai (Post 599651)

I think it's just mass flow rate. Hope this is helpful.

Hi musabai and other Dear foamers,

I want to simulate coal combustion in steady State but i couldn't find steady solver for it thus I solves it with coalChemistryFoam
which is transient until it reaches to steady state :(. Does anybody have better recommend?:)

Ok,
I modified coalCloud1Properties to this:

Code:

 type                       patchInjection;

            massTotal                 0.09167;

            parcelBasisType       mass;

            SOI                   0;

            patchName              in_1;

            duration              20; 

            U0                  (26 0 0);

            massFlowRate        0.004583;//kg/s

            parcelsPerSecond     1e5;

            flowRateProfile constant 1;

I know massFlowRate=0.00458 thus for 20 seconds (optional) I adjusted massTotal=0.09167 for massTotal/20=massFlowRate 0.004583.
Is this work right?

Is "flowRateProfile constant 1" right? I think it means to uniform profile for particle inject with 'massFlowRate= 0.00458'. Am I right?

I set 'parcelsPerSecond = 1e5' approximately. I don't know what must I put exactly. Is it a normal input for it?

I excuse because of my poor english writing.:)

Best Regards.

Quote:

Originally Posted by musabai (Post 599651)

I think it's just mass flow rate. Hope this is helpful.

injectionModels has an option "massFlowRate" thus flowRateProfile must be something else.

Hi...any one figured out what "flowRateProfile" stands for?

I am having a doubt whether it stands for mass flow rate as a function of time but then we do mention massFlowRate in injection model, then why to mention it again?

FlowRateProfile is a means of varying injected mass flow rate with time by creating a time profile. If you go with the "constant" FlowRateProfile, only one flow rate value will be used throughout the injection period. Alternatively, you can vary the flow rate by making a table with different flow rates at different times during the injection period.

Dear Foamers,

I am trying to simulate a pure pressure driven flow through a nozzle using speayFoam in OpenFoam1812. I would like to obtain the mass flow rate through the nozzle. Here is the relevant info from sprayCloudProperties file:

Code:

    injectionModels

    {

        model1

        {

            type            coneNozzleInjection;

            SOI             0;

            massTotal       1e-5;

            parcelBasisType mass;

            injectionMethod disc;

            flowType        pressureDrivenVelocity;

            Pinj            constant 1e6;

            outerDiameter   2e-4;

            innerDiameter   0;

            duration        50e-3;

            position        (0 0.5 0);

            direction       (0 -1 0);

            parcelsPerSecond 20000000;

            flowRateProfile constant 1;

The problem is that (to my knowledge) both "massTotal" and "duration" should be specified even for the pressure driven flow. Consequently, wouldn't the mass flow rate be imposed to the domain as mass flow = "massTotal" / "duration"? :confused:

I really appreciate your thoughts on this.

Regards,
MJ

Quote:

Originally Posted by mm66 (Post 787343)

Code:

    injectionModels

    {

        model1

        {

            type            coneNozzleInjection;

            SOI             0;

            massTotal       1e-5;

            parcelBasisType mass;

            injectionMethod disc;

            flowType        pressureDrivenVelocity;

            Pinj            constant 1e6;

            outerDiameter   2e-4;

            innerDiameter   0;

            duration        50e-3;

            position        (0 0.5 0);

            direction       (0 -1 0);

            parcelsPerSecond 20000000;

            flowRateProfile constant 1;

Please help. Any idea/input would be appreciated, thanks

Quote:

Originally Posted by mm66 (Post 787343)

Code:

    injectionModels

    {

        model1

        {

            type            coneNozzleInjection;

            SOI             0;

            massTotal       1e-5;

            parcelBasisType mass;

            injectionMethod disc;

            flowType        pressureDrivenVelocity;

            Pinj            constant 1e6;

            outerDiameter   2e-4;

            innerDiameter   0;

            duration        50e-3;

            position        (0 0.5 0);

            direction       (0 -1 0);

            parcelsPerSecond 20000000;

            flowRateProfile constant 1;

So I ran two simulations with exactly the same settings except for the nozzle diameter to see if the mass flow rate would be different under pressure driven flow. And (weirdly?) the results were almost identical... So how can I obtain the mass flow as a result of pressure driven throttle through different nozzle sizes...? :confused: Any ideas?

Quote:

Originally Posted by chpjz0391 (Post 599874)

I am using patchInjection in denseParticleFoam.

My part of the code is:

Code:

injectionModels 

    {

        model1

        {

            type                     patchInjection;

            massTotal             190; 

            SOI                      0;   

            parcelBasisType    mass; 

            patchName           inlet;

            duration               10;

            parcelsPerSecond  100644;              

            U0                       (0 0 -1.0); 

            flowRateProfile constant 1;    

            sizeDistribution

            {

                type                 RosinRammler

                RosinRammlerDistribution

                {

                     minValue     5e-6;       // 5 micron

                     maxValue    1000e-6;  // 1000 micron

                     n                2.0;          // Tuning parameter of Rosin-Rammler distribution 

                     d                500e-6;     // The size at which 63% mass of particle passes

                }

            }

        }

    }

First question: I have two outlets. How do I know the distribution of how many or how much parcel is going to each outlet.

Second question: If I know the mass to feed (massTotal) and time of feed (duration) then I know the mass feed rate. If I know the mass to be fed in one second and Rosin-Rammler particle size distribution then one can calculate the mass based distribution, e.g. m1 mass of 5 to 100 micron particles, m2 mass of 100 to 200 micron particles, and so on. Knowing the mass and particle dia of each size class, one can calculate the number of particles/parcels in each size class. Sum of them is going to be total number of parcels. How this is different from the defined parcelspersecond.

I can see the following output in log file of denseParticleFoam:

Code:

Solving 3-D cloud cloud



Cloud: cloud injector: model1

    Added 10 new parcels



GAMG:  Solving for cloud:alpha, Initial residual = 5.02715e-07, Final residual = 5.02715e-07, No Iterations 0

Cloud: cloud

    Current number of parcels       = 46928

    Current mass in system          = 8.86257

    Linear momentum                 = (0.0156862 -0.0522058 -4.25903)

   |Linear momentum|                = 4.25938

    Linear kinetic energy           = 1.36956

    model1:

        number of parcels added     = 46933

        mass introduced             = 8.8635

    Parcel fate (number, mass)      : patch walls

      - escape                      = 0, 0

      - stick                       = 0, 0

    Parcel fate (number, mass)      : patch walls_rack

      - escape                      = 0, 0

      - stick                       = 0, 0

    Parcel fate (number, mass)      : patch inlet

      - escape                      = 0, 0

      - stick                       = 0, 0

    Parcel fate (number, mass)      : patch outlet_of

      - escape                      = 5, 0.000932727

      - stick                       = 0, 0

    Parcel fate (number, mass)      : patch outlet_uf

      - escape                      = 0, 0

      - stick                       = 0, 0

    Min cell volume fraction        = 0

    Max cell volume fraction        = 0.582124

    Min dense number of parcels     = 1.81128

With the above output, I can say that the parcel injection rate is as per defined earlier, i.e. 19 kg/s (massTotal = 190, duration = 10). Also, the number of parcel injection rate also seems to be correct, around 100644 parcels per second. Further, The output shows the cumulative number and cumulative mass of parcels escaped from the two outlets (outlet_of, outlet_uf). This is the information, I would like to get collected in a separate file which can be used later for plotting. Furthermore, though the above information provides cumulative number of parcels escaped from the patch, it does now show the size distribution of parcels. Suppose, you are having a gravity based separator, then it is obvious to investigate which size is moving downwards and which is moving upwards. Those two products shall be collected at different outlets (at top and bottom). I want that the details of such collection is written is a file.

Hey Rahulksoni,

I have the exact same problem as you and haven't found a way to solve it.
However, I noticed that your log file shows the parcel fate for multiple patches. Whenever I run DPMFoam or MPPICFoam I get the Parcel fate for only the system as a whole, how were you able to get the info for individual patches?