Hi all,

I am rtying to setup a simulation to show air flowing through a bore, and interfacing with a throttle plate. i have attached an image to illustrate. Basically i need floworks to show that a suction is being created due to the pressure drop, and give me a mass flow rate in lbs/hr. is this possible???? I have been trying for a while now with no luck. I know what the flow should be but when i run the simulation i get values no where near what they should be, so i have obviously missed something somewhere. i can provide any additional data if needed. Thanks in advance!

Tony

Symmetry? never used it. how do i invoke it? Getting ready to leave for te day, will have to try it in the morning. Thanks for the tips. i will give it a go, and post back tomorrow!

Tony

To do this, just right click on the "Computational Domain" icon in the analysis manager tree, and choose:

"Edit Definition".

Then, click on the "Boundary Condition" tab, and look at the drop-down adjacent to "At X min" or "At X max".

You can select either one of those and choose the item "Symmetry" in the drop-down. Click OK.

This action will re-set the computational domain appropriately (make sure to show the computational domain to verify it is now half-sized), and you will need to re-mesh. The benefit is a halving of the cell count and thus the computational requirements, too. The software will automatically locate a "slip-plane" type of boundary condition on that plane, so the flow will slip on it (no friction) and will not cross over or into the other half.

Hope this helps alot! - Tony

Forgive my ignorance, as i have zero Flow experience.....Would you mind publishing a revised version of my image showing you suggestions? As far as an equation goal???? no idea where to go with that. what kind of equation are you refering to? Thanks.

27.5 inH2O (60°F) = 0.9925 psi

I assume you are setting up for a .9925 psi pressure drop.

So if atmospheric is 14.7 psia (407.3 inH2O abs), then the other side of the throttle plate would be 13.71 psia (379.7 inH2O abs). Automotive manifold pressures are usually computed using absolute reference, although 28 inH2O is the standard pressure drop for flow testing.

If you want to use gauge reference terms, atmospheric is 0 psig (or 0 inH2O) and the other side of the throttle plate would be -0.9925 psig (or -27.5 inH2O).