[m_f]

Hello everyone,

I am actually working with ParaView. I would like to calculate the mass flow rate (thus in kg/s) throught a vertical slice (Normals : [ 1 0 0 ]).

Like everyone, I tried Google's HowTo, but everything I learn didn't work as expected.

I understood that surface flow filter can be used to calculate the flow rate through a slice. The value I obtained is not the value I expected.
Thus, my question is :

- Is the surface flow a flow rate (m^3 / s) or a mass flow rate ( kg / s ) ?

- Which surface is used to calculate it ? I was suprised that the Area given by Surface Flow filter is two times the real surface of the slice ?

I use ParaView 3.12.

Let me know if I am not clear enough.

Thanks by advance,

m_f

[Kojote]

Hi

I'm using swak4foam for this.
I have an internal faceZone here -> But i think you can use a slice, too.

{
type swakExpression;
valueType faceZone;
zoneName zone1;
outputControlMode timeStep;
outputInterval 1;
expression "phi";
accumulations ( sum );
write yes;
log yes;
}

and you get m³/s over time

Is that you were looking for? But of course you have to do it in OpenFoam.

Br

Christian

[jensi_t]

Hi Christian,

did you check whether it gives you the right results? I did exactly what you did, but in a steady state flow in a channel with an inlet and an internal faceZone i get two different values for the mass flow rate.
The solution is right (checked that in tecplot) but swak4foam does a wrong integration.
Here are my entries in the controlDict:

patchMassFlow
{
type patchExpression;
accumulations (
sum
);
patches (
core_inlet
bypass_inlet
);
expression "phi";
verbose true;
}

gives good results, and

x5_bp_mass_flow
{
type swakExpression;
valueType faceZone;
zoneName int_interior-x5-bp;
expression "phi*flip()";
outputControlMode timeStep;
outputInterval 1;
accumulations (
sum
);
verbose true;
}

is only about 75% of the actual massflow.

Has anybody an idea where my mistake is?

Thank you.

Jens

[jensi_t]

Okay I'm using foam extend 3.1 where the flip() function doesn't seem to work. Unfortunately there is also no orientFaceZone tool in fe3.1. In my case solved the problem by using mag(phi) instead of phi because i'm sure that there's no reversed flow.

[towanda]

Hello,
I also have to calculate the mass flow (in kg/s) over a patch for my problem. What it works for me is to develop my own calculation to have a little more control, based on the code in:

applications/utilities/postProcessing/patch/patchAverage

The things that I focus were:

1) read the density from the transportProperties dictionary
2) Analyze carefully the definition of massFlow, and modify how sumField is calculated .

Is another point of view to calculate the massFlow. Maybe it will help you.

Best regards