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-   -   Help Needed (http://www.cfd-online.com/Forums/fluent/47976-help-needed.html)

S April 18, 2008 16:19

Help Needed
 
Hi I am new to FLUENT. I am designing a 3d cooling channel in which Nitrogen is flowing thru. When I am assigning the boundary condition for the fluid, do i have to select it as moving reference or stationary. And when i selecet moving reference frame, is the X translational velcoity the velocity of the Nitrogen?

Thanks in Avance

vk April 19, 2008 10:10

Re: Help Needed
 
No need to define the moving reference. Don't mean that when nitorgen flows, fluid volume has to move. You can just give the nitogen velocity at the inlet and fluent will solve and give the results.

S April 19, 2008 11:37

Re: Help Needed
 
Thanks for the reply. I have few more doubts. I am defining the nitrogen flow as mass flow inlet. Is that correct.. while defining so, I am giving values for the mass flow rate in l/min. And while initializing the solution, do i have to give the X velocity (m/s)? What is this value? One more doubt. Suppose If i did everything, how can i plot the temperature of the nitrogen as a function of time, if i running the simulation, say for 10 secs.

vk April 21, 2008 10:24

Re: Help Needed
 
Mass flow inlet should be in kg/s. Convert l/min using density. initialiing give less velocity (not zero) 0.001 m/s. If u have to plot temperature vs. time, run the case in unsetady and you have write the case and dat files seperately for each time. or you can write surface monitor files at required time steps during run time.

S April 21, 2008 17:47

Re: Help Needed
 
Thanks. Still I am confused with plotting the nitrogen(fluid) temperature Vs Time. I ran the case with unsteady time option for 5 secs and also I had written the dat files also. Still I am not able to plot it. Can you explain me in detail.

Thanks

vk April 22, 2008 12:58

Re: Help Needed
 
you have to read each cas and dat file and take mass weighted average values at the required plane. With this you have to plot the graph using excel or something else.


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