[Gasification] tests to design a new cheap gasifier fan

jim mason jim at allpowerlabs.org
Sun Oct 3 05:33:27 CDT 2010


the rotor made from the spinning disk with vanes between we have not
yet tested.  we should i agree.  we have testing the one sided version
with vanes at various angles forward and back from perpendicular.  i
was surprised to find it makes little difference.  backward rake,
espeically curve backwards at the tip is done with pro fans to reduce
noise, not increase pressure/vac.  it actually reduces performance a
bit.

it has taken awhile to get through my head that these fans are working
as centrifugal devices, not pressure devices.  the blades are not
levers or pumps.  they are simple accelerators for air mass.   your
pressure/vac is coming from velocity and inertia/momentum.

this is why the tightness to the walls makes little difference.  i've
moved the rotor / wall tolerance around quite a bit and saw very
little diffference.  i've read this is also why you see less double
walled rotors that one might expect.  but i've yet to test this so
can't really say.  greg says he gets 25% more out of these types.

some devices in the weed blower vac world put vanes on both sides of
teh disk.  but i think this is to prevent the weeds from getting stuck
on the back of the disk.  see the toro blower for example of this.

arnt raises an interesting concern about the rotor bending.  the other
way to deal with this would be to make a full slot for the vanes, and
push the vanes through so they stick out on both sides.  put a hole in
the center so air can feed to both sides of the rotor.

and . . . i have to suggest it. . .

this might finally be a reasonable application for a tesla turbine.
many parallel disks, no vanes or welding.  problem is the distance
between the disks needs to be related to the laminar layer thickness
at the rpms one is running.  the distances are usually very small.
like a few 100ths of an inch.  these are difficult tolerances to
maintain with junk cut metal.

however, it begs to be tried.  we will soon here.  maybe at the
workshop next weekend.

j





On Sat, Oct 2, 2010 at 7:39 PM, Greg Manning <a31ford at gmail.com> wrote:
>
>
>  Greetings Jim, and list members.
>
>  Jim, if you want a better fan, (and cheaper), simply make 2 disks (one
> mounts on the shaft, the other has the larger hole for the inlet.)
>
>  then use strips of heavy tin (or light gauge metal) and form them into a Z
> shape (well, an L with a dog leg the other end, and the opposite way,
> somewhat like a "90 degree Z")
>
>  take these and pop rivet with STEEL rivets (NOT aluminum ones) so they are
> sandwiched between the two disks in a radial fashion (like your welded
> version on your site, BUT with the extra disk on the inlet side of things.
>
>  the extra disk should run as close as it can to the outer housing the
> Bernoulli principal will help stabilize the outer disk, and the outer disk
> will add about 25% more suction to the unit for the same RPM (therefore the
> entire unit could be built smaller and lighter).
>
> Greg Manning,
> Canadian Gasifier Ltd.
> Building Hi-Performance Gasifiers, Since 2001
>
> Brandon, Manitoba, Canada
> 1 (204) 726-1851
>
>
>
> -----Original Message-----
> From: gasification-bounces at lists.bioenergylists.org
> [mailto:gasification-bounces at lists.bioenergylists.org]On Behalf Of jim
> mason
> Sent: Saturday, October 02, 2010 4:58 PM
> To: gasification at bioenergylists.org
> Subject: [Gasification] tests to design a new cheap gasifier fan
>
>
> we've been doing some work lately to design a new fan/blower that will
> produce the needed vac and heat tolerance for gasifier operation.  as
> we all know, there is not an inexpensive source for such a thing from
> other industries and applications.  thus we had to build one for the
> early gek kits.
>
> the original gek fan proved to not be strong enough once we finally
> characterized the vac numbers that produce the flow/heat rates that
> correspond to full tar conversion.  the ejector/venturi solution we're
> using currently produces plenty of vac and is very flexible, but
> requires compressed air.  this is not good for many off grid
> situations.  thus we still need a good fan/blower source.  and one
> that works on 12vdc, not an ac source.
>
> here's the info an pictures of our recent tests to produce this.  we
> are working towards a much simplified solution that also gets rid of
> the welding to make it.  this is based on the common car/truck fasco
> type fan motor.
>
> http://gekgasifier.com/forums/showthread.php?t=455
>
> jim
>
>
>
> --
> ----------------------------------------------------------------------------
> --
> Jim Mason
> Website: http://www.whatiamupto.com
> Current Projects:
>    - Gasifier Experimenters Kit (the GEK): http://www.gekgasifier.com
>    - Escape from Berkeley alt fuels vehicle race: www.escapefromberkeley.com
>    - ALL Power Labs on Twitter: http://twitter.com/allpowerlabs
>    - Shipyard Announce list:
> http://lists.spaceship.com/listinfo.cgi/icp-spaceship.com
>
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-- 
------------------------------------------------------------------------------
Jim Mason
Website: http://www.whatiamupto.com
Current Projects:
   - Gasifier Experimenters Kit (the GEK): http://www.gekgasifier.com
   - Escape from Berkeley alt fuels vehicle race: www.escapefromberkeley.com
   - ALL Power Labs on Twitter: http://twitter.com/allpowerlabs
   - Shipyard Announce list:
http://lists.spaceship.com/listinfo.cgi/icp-spaceship.com




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