[Shomaz ul Haq]

Dear all,

Hello. Hope all are well. I am trying to use variable "Mass Flow" in an expression for bulk or mean temperature for flow in a pipe. I thought to check the value of this variable on a centerline as a graph but nothing shows. Why is that despite the fact that fluid is moving in pipe? How can I use this variable if it gives a zero value? When I used mass flow rate as "rho*(PI*R^2)*(Velocity Z)" it gives a value. Would be grateful for help. Hope to hear from someone. Thanks.

[Shomaz ul Haq]

Dear all,

Hello. Hope all are well. I would be extremely grateful for help. Hope to hear from someone. Thanks.

[-Maxim-]

I don't understand exactly what you are trying to achieve?
You can analyze the massFlow through a plane or boundary. Massflow through a "centerline" won't work.
Or how exactly does your expression look like?

[Shomaz ul Haq]

You are absolutely right. I understand better now. But still how can I graph mass flow rate along the length of the pipe in CFX-Post? Thanks.

[evcelica]

Use other variables like velocity, density, etc. that would give you what you want wouldn't it?

[Shomaz ul Haq]

Thanks evelica. I did just that. I am just trying to find out how to use Mass Flow variable. Does using Density*Velocity*3.142*Radius^2 gives the same value as Mass Flow? That is troubling me as mass flow rate is involved in the my calculation of bulk or mean temperature expression. Thanks.

[evcelica]

Velocity will be at that line, not across the whole pipe cross section.
Conservation of mass means your mass flow through the pipe will be the same through the pipe regardless of cross section changes.

[Opaque]

Mass Flow variable is not a typical CFD-Post variable. It is only defined at the inlet/outlet/opening boundaries if I recall correctly.

It is used for the Function calculator when doing massFlowAve, massFlowInt on those boundaries.

As far as I recall, it is not defined for any other locator; hence, the 0 value you are getting.

[Shomaz ul Haq]

You are absolutely right Opaque. Thanks.