CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   Autodesk Simulation CFD (http://www.cfd-online.com/Forums/autodesk-simulation-cfd/)
-   -   Intake manifold help! - Auto (http://www.cfd-online.com/Forums/autodesk-simulation-cfd/116080-intake-manifold-help-auto.html)

 worthidlj April 12, 2013 11:22

Intake manifold help! - Auto

Hi Guys + Gals,

I'm currently doing my final dissertation for a BEng through the Open University and trying to design a variable intake manifold.
I've used Inventor Pro to come up with an initial design and want to run a transient simulation to show the changes in flow/pressure during engine cycles. For the inlet I aim to use about 55m/s for the inlet pipe (should this be steady state or transient?) but I don't know what conditions the outlets should be.:confused:
I've created some discs that would cover the outlets, and protude inside slightly, to represent the inlet valves and calculated their position in respective of time for a certain rpm but don't really know how to use it as only downladed it a few weeks ago!
I also want to know how to create the animations and make them uploadable to something like youtue.
I've looked at the tutorials but don't completely understand the terminology.

Cheers,
David

 marktm250xc April 21, 2013 19:01

What are your objectives for the simulation. What insight do you need to see? If it is a balanced manifold with minimal pressure drop, you can set it up with your velocity condition at the inlet and P=0 at the outlets. If you truly want to see transient effects, the inlet would be P=0 and the each of the outlets (entrance to the intake valves) would have a transient volumetric flow condition based on the bore/stroke and crankshaft timing.

 worthidlj May 2, 2013 18:51

Quote:
 Originally Posted by marktm250xc (Post 422188) What are your objectives for the simulation. What insight do you need to see? If it is a balanced manifold with minimal pressure drop, you can set it up with your velocity condition at the inlet and P=0 at the outlets. If you truly want to see transient effects, the inlet would be P=0 and the each of the outlets (entrance to the intake valves) would have a transient volumetric flow condition based on the bore/stroke and crankshaft timing.
Thanks for the reply Mark, very useful (sorry I've not replied earlier; assignment waffle requirements and deadlines have taken priority recently:/)
When you say transient volumetric flow conditions, I have data showing CFM through the inlet port in relation to camshaft angle. Does this mean I would be able to use Helmholtz tuning to determine RPM value of the length of the intake runners of the model and transpose that in relation to CFM (i.e. For lenght X, RPM=Y, therefore at time=A, camshaft angle=B and CFM=Z...if that makes sense)?