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 Post subject: Openfoam
PostPosted: Tue Mar 23, 2010 3:19 pm 
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A post unashamedly aimed at a small section of the membership :lol:

Is it any good to someone who is completely clueless in the area of cfd programming.
I can look at pretty coloured pictured with swirly lines as good as anyone but I'd really like to be able to draw them too :D

I have a pet project (stock 202 inlet with acis gutted and a much butchered idea for it) but I don't even know where to start. How do you make models, wireframes etc

Alternatively is there better tool that doesn't involve extensive wallet lightening

Cheers


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 Post subject:
PostPosted: Tue Mar 23, 2010 8:05 pm 
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OpenFoam requires Linux - I downloaded it a while back but couldn't get it to run on my dual-OS machine when running Linux.

I prefer to use something like CATIA v5 to produce the solid models (it's what I use every day of the week), save them as IGES format and then import them into ANSYS to do all the clever bits (i.e. geometry refinement, meshing, pre-processing, processing and post-processing).

If you want one piece of software that does everything then SolidWorks is probably worth a look, its a fairly intuitive 3D modelling package with a built in analysis suite, called COSMOS. Which not only allows you to do CFD work, but also FEA and kinematics studies. I'm very impressed with it, but my loyalties lie with CATIA! :lol:


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 Post subject:
PostPosted: Tue Mar 23, 2010 9:47 pm 
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Hmm,

It did run on my oldmachine with Ubuntu 9.1

But I found it rather confusing and the roll your own doc package doesn't really explain the basic workflows.
Plus that machine is rather underpowered being a 1G pentium III

I'll see if I can get my hands on a CATIA "demo" package :lol:


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 Post subject:
PostPosted: Tue Mar 23, 2010 11:01 pm 
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If you can get hold of it I'd suggest that you try SolidWorks rather than CATIA as all of the functions are integrated within the same piece of software, meaning the part you've just modelled up can go straight into the CFD suite without and need to convert it into another format, and you can keep jumping backwards and forwards making tweeks as required.

With CATIA and ANSYS it's a matter of modelling the part in CATIA, saving it, starting ANSYS, importing into the geometry workbench, the bringing it into the meshing workbench, and then doing the CFD stuff through the CFX package. Which all gets very tedious when performing an iterative preliminary design on something like, hmm, lets say a dual-plenum manifold for example... :wink: :lol:

You can also find some very good tutorials online for COSMOS FLOWORKS:
http://www.meadinfo.org/2009/05/tutorial-for-cosmos-floworks-2009.html

Flow distribution in a manifold:
Image

Turbocharger:
Image

FEA on a conrod:
Image

Tubular manifold design:
Image


In fact, I may just have convinced myself to switch over to SolidWorks... :lol:


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 Post subject:
PostPosted: Tue Mar 23, 2010 11:07 pm 
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That's it,

I'm off for a cold shower :lol:

I'll see if I can find any, ahem, trial versions of SolidWokrs then


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 Post subject:
PostPosted: Tue Mar 23, 2010 11:41 pm 
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Blooming eck Dan thats impressive :shock: :shock: ......... your talents have been wasted m8. Why did it take you so long to join our happy band here :lol:

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1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp


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 Post subject:
PostPosted: Wed Mar 24, 2010 12:48 am 
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...just what i was thinking don!

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ST205 with a little help from a ST215...


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 Post subject:
PostPosted: Wed Mar 24, 2010 6:58 pm 
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Sorry guys I should have said but its not my work unfortunately, far too exciting for me... I design flying buses for a living.


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 Post subject:
PostPosted: Wed Mar 24, 2010 8:44 pm 
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That's a co-incidence

Years ago I worked at Penny and Giles designing boxes to record the after effects when you get it wrong :lol:

To the best of my knowledge there's yet to be a crash caused by an exploding black box but it's bound to happen now I've said that :(


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 Post subject:
PostPosted: Wed Mar 24, 2010 11:56 pm 
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Actually I may as well show you guys some of the recent modelling and CFD stuff I've been doing as part of research for my inlet manifold project.

CATIA model of a JUN-style 'swan neck' manifold to see how successful an attempt to spread the flow across the 4 runners using a stock centre feed position would be.
Image

1st try at a dual-plenum design - needed some serious tweaking.
Image

Another dual-plenum design based on one used in a TTE(?) Corolla
Image

Eddy formation/energy around inlet trumpet
Image

Vectors showing just how important the radius on the trumpet is due to the volumes of air sucked in from the side.
Image


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 Post subject:
PostPosted: Thu Mar 25, 2010 1:32 am 
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Dan wrote:
Sorry guys I should have said but its not my work unfortunately, far too exciting for me... I design flying buses for a living.
Chester+Flying Buses=Airbus Wings?

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp


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 Post subject:
PostPosted: Thu Mar 25, 2010 2:06 am 
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Regarding intake trumpets I have a Racecar Engineering article somewhere with some great CFD images of various radius designs. IIRC the conclusion was that constant radius design is the most efficient. I'll try and dig it out. Of course neither the OEM ST205 centre feed or ST215 side feed intake plenums use trumpets as such although the radius from plenum to runners looks to be constant radius.

I'm not aware that TTE ever fitted a dual plenum intake to the Corolla WRC in competition? All my photos show a relatively simple design with a slight velocity stack. I guess they could have tried it experimentally?

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp


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 Post subject:
PostPosted: Thu Mar 25, 2010 2:27 pm 
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TrackToyFour wrote:
Dan wrote:
Sorry guys I should have said but its not my work unfortunately, far too exciting for me... I design flying buses for a living.
Chester+Flying Buses=Airbus Wings?


Indeed, or rather one of the sub-contracting firms who actually do the design work for them. They just assemble the big Mechano kits at Broughton.

TrackToyFour wrote:
Regarding intake trumpets I have a Racecar Engineering article somewhere with some great CFD images of various radius designs. IIRC the conclusion was that constant radius design is the most efficient. I'll try and dig it out. Of course neither the OEM ST205 centre feed or ST215 side feed intake plenums use trumpets as such although the radius from plenum to runners looks to be constant radius.


An ellipse is the optimum shape, though a constant radius 'half-doughnut' style trumpet isn't far behind it.

While playing around with various dual-plenum configurations I have found some of my best designs have the entry slot pointing down vertically into the plenum near the back wall, and have trumpets protruding halfway into the plenum. Basically the air enters the plenum, runs down the wall, along the base up the other wall and then slows and drops into the runners. Quite an effective way to ensure that they are fed 'good' air.

TrackToyFour wrote:
I'm not aware that TTE ever fitted a dual plenum intake to the Corolla WRC in competition? All my photos show a relatively simple design with a slight velocity stack. I guess they could have tried it experimentally?


I'll dig the photos out later, I'm fairly certain that's what it came from though. Or possibly it's from the Bates Corolla running in Oz??? :?


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 Post subject:
PostPosted: Thu Mar 25, 2010 3:04 pm 
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Dan wrote:
Or possibly it's from the Bates Corolla running in Oz??? :?
When I was over in Perth for Rally Oz in 2005 the two Neil Bates prepared 3S-GTE RunX Corollas used a single intake plenum. It even had the TTE part number on the casting.</anorak mode off> :lol:

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp


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 Post subject:
PostPosted: Thu Mar 25, 2010 3:38 pm 
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I'd still be really interested to see how the 202 manifold works.

It's potentially a dual plenum setup but the second plenum is a resonator as opposed to a direct feed

A few pictures, courtesy of Celica Club

Dual plenum setup. The main plenum sits on the cam cover (not ideal I know) and has a direct port connection. Second ACIS plenum sits at the top of the manifold and can be switched via in via a VSV
Image

The ACIS plenum has a removable top. To me it looks like a really "simple" way of implementing a custom manifold - blank off the main plenum feeds and create a custom top cover for the ACIS
Incidentally, this approach also gives you an ITB setup :D
Image

The whole shebang is sitting on a lower manifold section which connects to the ports. This might also provide a simple base on which custom plenums can be built.
You can also see the main plenum connection to #1 cylinder below the ACIS butterfly
Image

EPC breakdown
Image


I just keep looking at this and thinking that somewhere in there is a nice turbo setup that just needs a bit ( :lol: ) of fabrication. It's got to be easier than a complete design from scratch

What I really wonder is if you could cut the main plenum off and re-jig it so that it connected to a custom cover for the ACIS plenum but I don't know how effective the dual plenum setup would be with the plenums interconnected by individual runners

I also keep thinking about moving the injectors into the defunct main plenum runners. This would give a much greater distance from injector to port. Or maybe connecting a set of secondary injectors there for high rpm/boost use

Sooo many ideas, so little talent/motivation :(


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