Non-Return Valve Through Porous Region

AMS85 · May 21, 2015, 04:40

Hi! I'm simulating a small system of pipes with a recirculation loop, and I'm having issues with backflow around the loop, therefore I'd like to introduce a non-return valve into this loop to ensure flow only goes in the correct direction.

I'm assuming it can be done by creating a small porous region in the line and manipulating the various resistances so I can only have flow in the +X direction, however I'm not having any luck so far.

Any ideas would be appreciated!

ggulgulia · May 21, 2015, 23:42

Hi AMS85

If you are simulating the NRV using porous media, this implies you can only simulate the pressure drop characteristics of NRV, and that too assuming uniform flow through NRV. I am not sure how a flow through NRV will be uniform at all unless it's laminar.

In any case, if you would want to proceed with this method, you should calculate the pressure drop characteristics of NRV at multiple velocity points, i.e

PD = (TP@Inlet-TP@Outlet)

at a given velocity and plot the same using some tool (excel for eg) with velocity on x axis and PD on y-axis. Use 2nd Degree polynomial curve fitting and the coeff of X^2 gives the value of (alpha*L) and the coeff of X gives the value of (beta*L), where L is the thickness of the NRVUse the alpha and beta values for the porous coefficients.

Hope this was helpful

ggulgulia · May 22, 2015, 02:37

btw I forgot to mention that one of the intermediate velocity points for porous calculation should be the one that you will be using for your actual simulation

AMS85 · May 22, 2015, 03:42

Hi ggulgulia, thanks for the reply. Apologies I wasn't clear in my explanation of what I'm trying to do. I'm not simulating an actual valve as such, I just want to force the flow into one direction and not allow backflow. I figured I could do this by creating the porous region and giving it resistance only in the directions I don't want flow to occur, however I can only seem to set resistances in x y and z in general, so whilst I can stop y and z direction flow, I can't stop negative x flow, which is actually the problem I'm trying to stop.

ggulgulia · May 23, 2015, 04:10

Hi

Modeling the actual valve will be the solution I suggest.

Sachin m · September 24, 2020, 06:18

Quote:

Originally Posted by AMS85

Hi! I'm simulating a small system of pipes with a recirculation loop, and I'm having issues with backflow around the loop, therefore I'd like to introduce a non-return valve into this loop to ensure flow only goes in the correct direction.

I'm assuming it can be done by creating a small porous region in the line and manipulating the various resistances so I can only have flow in the +X direction, however I'm not having any luck so far.

Any ideas would be appreciated!

Does any body have a solution to this problem.

May 21, 2015, 04:40	Non-Return Valve Through Porous Region	#1
AMS85 New Member Join Date: Dec 2014 Posts: 3 Rep Power: 11	Hi! I'm simulating a small system of pipes with a recirculation loop, and I'm having issues with backflow around the loop, therefore I'd like to introduce a non-return valve into this loop to ensure flow only goes in the correct direction. I'm assuming it can be done by creating a small porous region in the line and manipulating the various resistances so I can only have flow in the +X direction, however I'm not having any luck so far. Any ideas would be appreciated!

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May 21, 2015, 23:42		#2
ggulgulia Senior Member Gajendra Gulgulia Join Date: Apr 2013 Location: Munich Posts: 144 Rep Power: 13	Hi AMS85 If you are simulating the NRV using porous media, this implies you can only simulate the pressure drop characteristics of NRV, and that too assuming uniform flow through NRV. I am not sure how a flow through NRV will be uniform at all unless it's laminar. In any case, if you would want to proceed with this method, you should calculate the pressure drop characteristics of NRV at multiple velocity points, i.e PD = (TP@Inlet-TP@Outlet) at a given velocity and plot the same using some tool (excel for eg) with velocity on x axis and PD on y-axis. Use 2nd Degree polynomial curve fitting and the coeff of X^2 gives the value of (alphaL) and the coeff of X gives the value of (betaL), where L is the thickness of the NRVUse the alpha and beta values for the porous coefficients. Hope this was helpful

May 22, 2015, 02:37		#3
ggulgulia Senior Member Gajendra Gulgulia Join Date: Apr 2013 Location: Munich Posts: 144 Rep Power: 13	btw I forgot to mention that one of the intermediate velocity points for porous calculation should be the one that you will be using for your actual simulation

May 22, 2015, 03:42		#4
AMS85 New Member Join Date: Dec 2014 Posts: 3 Rep Power: 11	Hi ggulgulia, thanks for the reply. Apologies I wasn't clear in my explanation of what I'm trying to do. I'm not simulating an actual valve as such, I just want to force the flow into one direction and not allow backflow. I figured I could do this by creating the porous region and giving it resistance only in the directions I don't want flow to occur, however I can only seem to set resistances in x y and z in general, so whilst I can stop y and z direction flow, I can't stop negative x flow, which is actually the problem I'm trying to stop.

May 23, 2015, 04:10		#5
ggulgulia Senior Member Gajendra Gulgulia Join Date: Apr 2013 Location: Munich Posts: 144 Rep Power: 13	Hi Modeling the actual valve will be the solution I suggest.