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-   -   Determine mass flow rate along flow path (http://www.cfd-online.com/Forums/cfx/19920-determine-mass-flow-rate-along-flow-path.html)

Atit Koonsrisuk October 4, 2003 10:54

Determine mass flow rate along flow path
 
I would like to determine the mass flow rate along the flow path to check if it satisfy conservation of mass law. I use function 'massFlow' in the 'Calculator' tool of 'CFX Post'. 'Calculator' need 'locator' for calculation, then the result will be gotten at only some planes created. Could somebody please suggest me how do I get the mass flow rate along the flow path? In addition, I would like to get the kinetic energy along flow path. Because of non-uniformity of the properties across the flow area, I can't use the properties along the 'streamline' and use it as the representative at each X-section. I would like to use 'massFlowAve' in 'Calculator', but I got the same problem concerning the 'locator'. Do anyone have the suggestion? Thank you very much.

Robin October 4, 2003 16:24

Re: Determine mass flow rate along flow path
 
Atit,

Create a slice plane which cuts through your flow path and calculate your mass flow at that slice plane.

The solver is stongly conservative. If you just want to know if mass is conserved, look to your residuals. If the mass residual is small, conservation of mass is acheived. The solver also outputs global balances on all equations, including mass, at the end of the run in the OUT file. Have a look there, if you solution is converged, mass is typically conserved globally to within ~.01%, well within roundoff.

-Robin

Atit Koonsrisuk October 5, 2003 04:47

Re: Determine mass flow rate along flow path
 
Thank you for you answer, Robin. Furthermore, I would like to calculate the power of flow along the flow path. It is P=0.5x(mass flow rate)x(velocity)^2. How do I get it? Thank you in advance.

Atit


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