How to calculate DPM particle flow rate for a 2D axisymmetric case
 

Given the 2D geometry with an axis, how do we calculate the flow rate?

Geometry: Attachment 78565 Inlet : Attachment 78566

Surface injection = inlet (6 mesh grid points) , mass flow rate = 3.6513e-6 kg/sec , density = 1.6228 (kg/m3) , Such that wolume flow rate per grid point ( at inlet ) = 2.25 cm3/sec .

While applying the axisymmetric case, how will we be able to calculate net flow rate? Had it been a 3D case, I would have multiplied it with the total number of mesh points on the inlet surface. But how may this be in a 2D axisymmetric case?

Thanks

2D axisymmetric
 

It does not matter whether it is 2D or 3D. It is always the number of mesh points - face centers in case of 3D, and edge centers in case of 2D.

total flow rate?
 

Okay, so the total flow rate will be? As you may see from the image there are 5 edges, so will this be equal to = 5* (flow rate of 1 point)

Another question is how will this map to the real case? As we have the axis boundary condition. Since the experiment is actual 3D, What flow rate should I consider in the experiment?

Will it be the same, flow rate= 5*(flow rate of 1 point)

Thank you.

Flow Rate
 

The flow rate applied for a particle injection is never per edge or per face; it is always total flow rate. Its division across faces or edges also depends on the user; it could be set to uniform or non-uniform. However, the flow rate, for discrete as well as continuous phase, in case of an axisymmetric simulation, has to be equal to that for full region, i.e., equal to what you have in the experiment or the real scenario.

experimental flow rate value?
 

I wanted to know that while I'm using this setup Attachment 78586 at the inlet, how may I find the volume flow rate of the gas which it would correspond to in the actual experimental setup?

given dpm particles (argon gas) density = 1.6228 gm/cm3.
mass flow rate = 0.01 kg/sec
inlet & geometry = already shown in the previous reply above. ( 30 mm in length with 5 edges in the mesh and axisymmetric condition )

With all this information how will I be able to find the volume flow rate which I will set in my experimental setup?

Thank you.

Volume Flow Rate
 

Volume flow rate is independent of particles or droplets. It is ratio of mass flow rate and density. So, 0.01 / 1.6228. The density value is correct, but the units you mentioned is wrong. The volume flow rate calculated is for full, circular duct.

calculations
 

so it comes as (0.01 kg/sec / 1.6228 kg/m3 ) = 0.0061621888 m3/sec that is 0.0061 * (1000 * 60 ) = 369.73 lt/min.

Will this be the flow rate I would be required to set in the experimental inlet, which is a circular pipe of diameter 60 mm?

Model ( 2D axisymmetric ) = Attachment 78589

Experimental setup = Attachment 78590

May you please have a look at the above pictures for reference.


Thank you for all the help.

Volume Flow Rate
 

Where does 1000 come from? Is it the density of the continuous phase?

Do note that axisymmetric model is valid only for the central inlet.

1 m3 to 1000 litres. yes for central inlet only. is it right?