[CFXer]

Hello.

I'm doing flow simulation of the picture's structure.

The flow in with 2 y-direction (upward and downward).

I have many rectangular channels that fluid is flowing through.

To check flow distribution, I used iso-clip in CFD-post.

Using that, I plotted mass flow rate of each plate.

But it has a problem.

Obviously the total mass flow rate is 12.55kg/s.

But as I calculated summation of each plates' mass flow rate, it is different with the plane's position(z axis).

And it's total mass flow rate doesn't 12.55 kg/s, it shows 11, 15, 30......

When I calculated mass flow rate of whole plane, it shows 12.55 kg/s, but when I calculated each iso clips' sum, it doesn't show 12.55

I don't know what's the problem... Please help me.

[ghorrocks]

How did you calculate the mass flow rate of each duct?

[CFXer]

Thank you for your fast reply.

I used "=massFlow()@Iso Clip 1 , =massFlow()@Iso Clip 2 .... =massFlow()@Iso Clip 202" its sum shows different from 12.55

When I used "=massFlow()@plane" , it shows 12.55.

[CFXer]

Originally Posted by ghorrocks

How did you calculate the mass flow rate of each duct?

For more information, Some iso clip is like this picture.

[ghorrocks]

We really cannot debug this for you. There are just so many things you need to check - is the isoclip the same plane as plane1? Have you missed a duct? Is the function wrong on one duct?

All I can say is that when it is done correctly the flow rate of the large number of ducts will be the same as the sum of the flow rates of each individual duct. You just need to find what mistake you have made in calculating it.

[CFXer]

Thank you for your response.

I checked what you said : the isoclip is on the same plane --> I made isoclip by using that plane.

I think applying location paramter of ducts are not wrong.


And I want to ask one more thing.

In one duct, its mass flow value differs with z value (flow direction)

when z=0.002m, m=0.55 , when z=0.3m, m=0.15...

In every z value, "=massFlow()@plane" shows 12.55, but sum of each isoclip shows larger value in the middle position of the duct : z=0.002m -> 11 kg/s, z=0.3m -> 30kg/s.

Could you debug this thing? I really don't know why this happens....

[JonasII]

Hello, William!

Have you solved problem, described in this topic?
I have similar, with Iso clip tool...
How to split air blade in CFX Post without loosing accuracy

Maybe you can help me?

[CFXer]

I think the problem of my simulation is on the porous domain.

In porous domain, it has porosity parameter so it affects the mass flow rate.

So if I divide the porosity value with each plane's mass flow rate, it shows about 12.55 kg/s.

[JonasII]

Thanks for yours reply.
In my case, I think, I need work with postprocessor, but I don't know where the problem is and where to start...