CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   How to define a mass source at a velocity inlet ? (http://www.cfd-online.com/Forums/fluent/72696-how-define-mass-source-velocity-inlet.html)

cfdiscool February 15, 2010 11:26

How to define a mass source at a velocity inlet ?
 
Hallo all

I am trying to define a mass source where the high pressure water should be supplied, this is thorough nozzle, I defined the nozzle volume(int) as fluid and now when i turn on the mass source term I see that i have to define the mass source per unit volume

units are kg/m^3-s

what is this unit volume ? i have a numerical value of mass flow rate at the inlet of this nozzle which i have in kg/s... what is the unit volume in this case ...a cell or entire volume of the nozzle...

any suggestions please???

thanks:)

CFDtoy February 17, 2010 11:57

mass source
 
Code is Finite Volume My friend. so, define, mass per volume please. Basically, we do

d(rho)/dt*Vol(cell) + sum (flux) = Source *volume (cell)

Before solving the problem, volume is multiplied to the entire eqn in the Finite Volume method.

You provide per volume and it will compute the source appropriately.

btw, if it asks for per volume, it is the cell volume not the nozzle.

Hope this helps.

/CFDtoy


Quote:

Originally Posted by cfdiscool (Post 246087)
Hallo all

I am trying to define a mass source where the high pressure water should be supplied, this is thorough nozzle, I defined the nozzle volume(int) as fluid and now when i turn on the mass source term I see that i have to define the mass source per unit volume

units are kg/m^3-s

what is this unit volume ? i have a numerical value of mass flow rate at the inlet of this nozzle which i have in kg/s... what is the unit volume in this case ...a cell or entire volume of the nozzle...

any suggestions please???

thanks:)


cfdiscool February 17, 2010 12:22

After a long and long head scratching i found out the fact behind this unit system....

answer to my question can be as follows:

the mass source per definition in FLUENT is per unit volume...

so mass source has units as kg/s in SI units , since all sources are to be assigned in SI units
The units of "unit volume" is m^3.

This "unit volume" can be a single cell where the source lies or a fluid domain which acts as your source.

simply to input the value of mass source one needs to do following

(mass flow rate)
-------------------------------- units are (kg/s)/m^3
(volume of the source)

volume of the source = (surface are of the source zone)*(height of the source zone)


please correct if am wrong

wishes

KOX September 4, 2011 11:59

answer + another question
 
Hi there

I think you interprete corectly how the mass source works. I think the same.
However could you tell me please if this mass source works in your model, whatever you were trying to simulate? In my case even if I set some certain value (kg/(m^3*s)) the mass sourc doesnt work. There is nothing released from the source even if I add additional momentum source.
Help please

PN

rahulhkumar02 June 26, 2014 03:00

2D mass source flow
 
Hello friends,
I am working on a film cooling simulation in a 2D geometry with Fluent. Ansys Workbench 14.0 is used. For this I am using a mass source for the coolant chamber . But, before going to the exact problem, I need to validate the method of use of source flow in 2D, either in a simple duct or pipe flow cases. Please suggest me with links or articles where a simple 2-D mass source problem is dealt in Fluent. Hope someone help me soon.
Thank you.


All times are GMT -4. The time now is 14:50.