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Keith Oakley - n/a
5-Nov-08, 01:42 PM
As part of the research programme into Fan Noise I'm working with the University of Hertfordshire on a CFD (Computational Fluid Dynamics) computer model of a typical Light Hovercraft fan setup. The aim is to identify and quantify typical sources of turbulence generated noise to compare and contrast with the pictures we're seeing from Noisecam and other practical tests. We need an accurate CAD model of a (say 5Z) Fan blade to feed into the model. Does anyone in our wide circle of expertise have access to a Laser scanner that could do this?

jon_curtis - n/a
5-Nov-08, 05:08 PM
ah, you beat me to it! http://hovercraft.org.uk/images/icons/smiley_icons/icon_smile.gif



Hi Keith, i work as a mechanical and thermal design engineer for a large multinational aerospace company, as part of my day job, i use EFD pro, which is a CFD add on to our drawing package Pro/engineer. I have been spending a bit of time building a model to run in our CFD packaging over the last few weeks. My aim was to run a duct model and with the results from this, do a complete craft with airflow through the plenum and skirt.



I to am after a decent fan blade model, i have a simple model of a fan blade (attached) however this is not the true geometry of a multiwing blade.

I have a model of one of kens 925mm intergrated ducts, with a t bar i have been working on. see pic



index.php?t=getfile&id=1921&private=0



With regards to 3d scanning, i have not had wonderfully good experiences of what these things can produce, however perhaps the tech has come on in the last few years. The best bet would be to contact multiwing or hascon direct as they will certainly be able to supply a 3d model of a blade, however when i asked they would not supply to me, you might have more luck, perhaps the uni you mentioned might be able to setup something?



if you do manage to get one, i would be interested in it and perhaps we can compare results. anyhow i have tried to attach IGES files of the pic above,but it will not let me, if you give me your email address will send it that way.



perhaps the duct model will come in handy, its exact to Kens 925 ducts.



cheers

jon



just had a thought a stereolithography company we use might be able to scan a blade www.arrkeurope.com/services/sla/

Keith Oakley - n/a
5-Nov-08, 05:48 PM
Thanks Jon - I knew there was a lot of skills out there we could tap into. Your duct models would be very welcome -Anything we can do to speed the CAD capture, and then build the model would be great. Then we can get to focus on the really interesting bit which is to understand much better the many sources of turbulence generated noise we've identified with noisecam, and perhaps work out some fixes. At the moment we seem to have around 9dba more fan noise from my F25 than Multiwing say that particular fan should produce 'in perfect conditions'. With many higher powered craft that seems to be more like 15dba.



Can you send me the stuff via the personal message facility on this board plse? Anyone else wanting to contribute perhaps privately can contact me via this route.



Keith

Ian Brooks - n/a
5-Nov-08, 10:40 PM
It may be possible to have one measured on our coordinate measuring machine - but I don't have one to measure right now. If you have no joy, send me one and I'll see what can be done.



Ian

Mart366 - n/a
30-Nov-08, 09:11 PM
If i recall Faro, do a 3D scanning head, and is an impressive bit of kit.



We looked at purchasing one earlier in the year, the guys came



down and scanned a colleague's hand, then sectioned it, and did



some detailed measurements of the insides of his fingers lol





Very good kit, but not sure of the budget.



Although i do recall some places often hire out kit





mart