CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   need clarification (http://www.cfd-online.com/Forums/cfx/105963-need-clarification.html)

 shaswat August 14, 2012 04:03

need clarification

Dear friend

I am doing simple flow analysis . This is transient analysis.
Input is a variable pressure ( average pressure is 12000 pa -all the time) outlet pressure should be 0 Pa. with this condition I would like to increase the flow rate .I don't know the initial condition.

I did as follows

I set the average pressure at the inlet and average velocity at the outlet .I varied the out let velocity when i need more flow.I did n't change the inlet pressure all the time.

2. Transient analysis

end of steady state configuration I did the transient analysis now I use transient pressure at the inlet and I put 0 Pa at the outlet.

I want to know is this correct way of setting different flow rate when the pressure doesn't change at the inlet and outlet all the time.

Regards

Shashwat

 ghorrocks August 14, 2012 07:58

I do not understand your question.

Did you do a steady state simulation as an initial condition for a transient simulation? What are you trying to model with the transient simulation? What is the problem you are seeing?

 shaswat August 14, 2012 08:20

flow analysis in a stenosed artery

Quote:
 Originally Posted by ghorrocks (Post 377019) I do not understand your question. Did you do a steady state simulation as an initial condition for a transient simulation? What are you trying to model with the transient simulation? What is the problem you are seeing?
Yes I did steady state analysis simulation as an initial condition for a transient simulation.
My question is
I would like to do simulation for different flow rate keeping transient inlet pressure and outlet pressure constant

For example :

my flow rates are 50ml/min, 60ml/min, 100 ml/min etc
But I have to maintain the inlet pressure ( transient) and outlet pressure 0 Pa constant all the time for the above flow rates.

Thank you

Regards

Shashwat

 bratzinger August 14, 2012 08:34

if you set the pressuredrop (inlet-outlet) in your fluid-domain you get a massflow as a result

if you set the massflow and outlet pressure(e.g. 0 Pa relative) you got the inlet pressure as a result

how can you vary the massflow in your geometry without affecting the pressuredrop? (1st law of thermodynamics or in simple cases without any work(vent...) or heat flux bernoulli equation)

 All times are GMT -4. The time now is 08:03.