I own a small high-performance machine shop in Riverside, CA. I have been trying to determine different designs for the intake ports of the cylinder heads that I am working on. Currently I am doing all of the changes and modifications to the ports by hand and then checking the results on a flowbench.

My question is pretty simple:

What kind of software do I need to model the shape of the port and how do I determine what the flow in CFM would be in the port? Is CFD capable of giving me accurate information in regard to my application? Can I model the intake valve opening .050" up to .650" to see how the flow will change with valve lift?

Anyone out there who understands the operation of an internal combustion engine will understand what I am trying to do. PLease let me know if CFD is what I need and what software you would recommend. Thanks

Cameron Goodale

Specialized Motor Service

I think many CFD program can do this , i use CFDRC and ever seen ur case in its tutorial. The whole intake pipe , intake valve , combustion chamber/ piston can be simulated. Program can give results : air flow rate, pressure loss etc.

G' luck

Hi Cameron,

There are probably a number of CFD codes that can do what you want, I think that Star-CD has quite a strong presence in engine simulation and moving meshes(It is the tool I am using, though I am not working with engines at the moment). Having practical IC engine experience you will probably have a good feeling for the boundary conditions and important parameters, however it might be wise to talk to some CFD consultancy if you are not yourself a CFD expert. Even though some sales people maybe tell a different story, CFD is still a difficult game.. And the analysis you describe is a transient(time dependent) case with moving geometry, you will also have timedependent boundaries influenced by pressure waves.

For detailed understanding of the design parameters of your problem there is no better way than CFD i think.

There is also a few good text books around for manifold design and pressure wave action, which might have some information of use to you when it comes to engine tuning.(Try Pearson and Winterbone.'Design Techniques for Engine Manifolds: Wave Action Methods for Ic Engines').

Best of luck in your pursuit for power.

Paal