CFD in combustion chamber design.

[godlameroso]

Is this something that is regulated by the FIA similar to aerodynamic CFD?

[Joseki]

I think the only restriction the engine manufacturer have is the tokens system.

[Pierce89]

Cfd for "cooling only" or in the PU is not covered in the RRA.

[PlatinumZealot]

CFD is not advanced enough yet to simulate high speed combustion in an accurate manner. Mostly in cylinder aero and heat transfer it is used for i suspect. Combustion is more of a build and test sort of thing.. That is why it is so difficult and takes so long to develop.

[IVX8]

If I had a good CFD Model for combustion I don't think i would admit to it.

[Brian Coat]

For GDI combustion the development of the air & spray pattern are extremely important which is prime CFD territory.

The CFD work is a key precursor to the single cylinder engine testing.

[PlatinumZealot]

Yeah spray pattern and mixing dynamics CFD can do for sure. I have seen that.

I am not any authority on CFD of course (i wish) but combustion itself at high speeds see in a piston engine i personally have never seen that before in CFD.

In combustion there are chemical reactions with different species going on. Radiation. Evaporation. Dissociation. Heat transfer all in a fraction of second. I never heard it mentioned or seen all of that rolled into one in cfd.

It would be delightful if anyone has any experience in this can enlighten me. But i sticking with experience and common sense to go out on a limb and say that CFD use for simulating a combustion event in a piston engine is very limited if it is indeed used.

I will gladly put my foot in my mouth t o. Haha

[gruntguru]

https://www.avl.com/web/guest/-/avl-fire-engine

[PlatinumZealot]

Yes. I am aware of those things on that site. You can design the combustion chamber using CFD. There are so many influences on the combustion chamber design..

But my point is that I have never seen a CFD simulation use to investigate a literal combustion in a piston engine.

Never seen it or heard of it. There are approximations of a combustion to solve other problems. You can use a mathematical model you can set up the pressure and radiation to rise with time, increase the fraction of other gasses with time. But this is all based on what you got from a physical experiment. Things happening in the chamber won't feed back and affect the combustion in the simulation.

If there was a video or something...

[riff_raff]

https://en.wikipedia.org/wiki/KIVA_%28software%29

[PlatinumZealot]

OK. Thank you guys. (Riff Raff and Guru)

I had to play devils advocate and squeeze the spongy grey matter a bit, if you know what I mean. I gladly admit to my ignorance.

So KIVA it is... I will check this one out for sure...

KIVA is a family of Fortran-based Computational Fluid Dynamics software developed by Los Alamos National Laboratory (LANL). The software predicts complex fuel and air flows as well as ignition, combustion, and pollutant-formation processes in engines. The KIVA models have been used to understand combustion chemistry processes, such as auto-ignition of fuels, and to optimize diesel engines for high efficiency and low emissions. General Motors has used KIVA in the development of direct-injection, stratified charge gasoline engines as well as the fast burn, homogeneous-charge gasoline engine.[1] Cummins reduced development time and cost by 10%–15% using KIVA to develop its high-efficiency 2007 ISB 6.7-L diesel engine that was able to meet 2010 emission standards in 2007. At the same time, the company realized a more robust design and improved fuel economy while meeting all environmental and customer constraints.[2]

[Brian Coat]

This is interesting ...

https://dspace.lboro.ac.uk/dspace-jspui ... singhe.pdf

[3jawchuck]

May also be interesting to those in this thread.

http://urn.fi/URN:ISBN:978-952-60-6724-7

[godlameroso]

I wonder how much time they spend creating the mesh for the valve port angles.

[PlatinumZealot]

Shouldn't take long. The computer does most of it. Meshers are smarter and smarter these days. The solid mesh is the least of their worries. And the fluid mesh - the most you can do manually is increase mesh detail where u need and reduce where you don't.