New and Improved Lady Anne

Moderator: Mike Everman

Post Reply
larry cottrill
Posts: 4140
Joined: Sun Oct 05, 2003 1:17 am
Antipspambot question: 0
Location: Mingo, Iowa USA
Contact:

New and Improved Lady Anne

Post by larry cottrill » Thu Oct 12, 2006 4:55 pm

A few days ago, Graham Williams emailed me with a re-proportioned Lady Anne Boleyn layout that should significantly improve performance, at least in terms of total thrust. While I definitely won't claim anything for an engine I haven't built yet, Graham said that the theoretical maximum thrust for this modified version, burning alcohol, is close to 4.9 lbF (about 2.3 kgF) !!! If this proves out, we are finally in the Dynajet performance range with a valveless engine of similar size. Graham's work was done with his NUDIS development; I verified the improvement in massflows using UFLOW1D (but it does not reveal a thrust figure, of course). Basically, some intake velocity has been sacrificed for greater massflow and the tailpipe massflow is improved by taking on a heavier "tail piston" (cool air pulled in from behind).

The intake is enlarged significantly, and moved forward radically. Every cone has changed except the front dome. The chamber and the middle cone have been significantly shortened. The choke cone has been lengthened a bit. The tail cone has been lengthened, and its outlet ID increased to a full 64mm - same ID as the front of the chamber! The tail cone now takes up 45 percent of the engine length, and about half of the total engine volume! One important change is REDUCING the nozzle (rear ID of chamber / front ID of middle cone) slightly, from 32 to 29 mm. DO NOT INCREASE THIS ID !!! Graham established that opening this back up to 32mm (a change of just 3mm) significantly REDUCES thrust development - and I was able to verify the negative effect for myself with UFLOW1D. The new dimensions are shown in the scale drawing attached below.

The complete cone sheet dimensions for Lady Anne Boleyn Rev. 02 are as follows (from Eric's Pulsejet Calculator, of course):

Code: Select all


Cone             R1(mm)             R2(mm)               Angle (deg)
--------------------------------------------------------------------
Front dome            8                 36                    319.39
Chamber cone        314                142                     36.65
Middle cone         183                266                     28.45
Choke cone          161                123                     46.96
Tail cone           244                487                     23.65

Note that achieving maximum performance will depend on optimal fueling - the fuel spouting point shown in the drawing is meant as a starting point for experimentation, and is probably suboptimal.

Good luck!

L Cottrill
Attachments
FWE_VIII_Lady_Anne_Boleyn_Rev02_scale.gif
Lady Anne Boleyn Rev. 02 scale drawing. Note that the fuel spout location shown is not necessarily optimal - the correct point should be located experimentally. Drawing Copyright 2006 Larry Cottrill
FWE_VIII_Lady_Anne_Boleyn_Rev02_scale.gif (12.9 KiB) Viewed 7685 times

hagent
Posts: 413
Joined: Sun Feb 06, 2005 9:01 pm
Antipspambot question: 0
Location: Simi Valley CA

re: New and Improved Lady Anne

Post by hagent » Thu Oct 12, 2006 5:48 pm

Very nice Larry!

Does that "second" chamber help with combustion?

Hagen
Hagen Tannberg

larry cottrill
Posts: 4140
Joined: Sun Oct 05, 2003 1:17 am
Antipspambot question: 0
Location: Mingo, Iowa USA
Contact:

Re: re: New and Improved Lady Anne

Post by larry cottrill » Thu Oct 12, 2006 6:00 pm

hagent wrote:Very nice Larry!

Does that "second" chamber help with combustion?

Hagen
The mid-section basically helps with wave shaping and event timing. I think one basic effect of the choke (the second nozzle) is to partially reflect the positive pressure wave back to the front and out the intake. Things get complicated to think about, though, when you start to re-shape the wave path; only Graham knows for sure, since he worked out the "Type 07" tailpipe on which the Lady Anne is based.

Now, if somebody will just build one, like James D did with the original design ...

For anyone who hasn't seen it, the original build and test run is here:
http://www.pulse-jets.com/phpbb2/viewtopic.php?t=3271

L Cottrill

leo
Posts: 380
Joined: Sat Feb 26, 2005 5:53 pm
Antipspambot question: 0
Location: netherlands
Contact:

re: New and Improved Lady Anne

Post by leo » Thu Oct 12, 2006 7:09 pm

I like the inlet almost on the front, has anyone run a jet with that kind of inlet?.
Jmir posted one but never report on it running.
Maybe I try that inlet configuration one time.

Mike Everman
Posts: 4894
Joined: Fri Oct 31, 2003 7:25 am
Antipspambot question: 0
Location: santa barbara, CA
Contact:

re: New and Improved Lady Anne

Post by Mike Everman » Thu Oct 12, 2006 9:33 pm

Faaaascinating!
Mike
__________________________
Follow my technical science blog at: http://mikeeverman.com/
Get alerts for the above on twitter at: http://twitter.com/mikeeverman

larry cottrill
Posts: 4140
Joined: Sun Oct 05, 2003 1:17 am
Antipspambot question: 0
Location: Mingo, Iowa USA
Contact:

re: New and Improved Lady Anne

Post by larry cottrill » Fri Oct 13, 2006 12:29 pm

If anyone is seriously interested in building one of these, I can develop full size cone sheet patterns for you to use. This will take a while to do, though.

L Cottrill

Eric
Posts: 1859
Joined: Sat Oct 04, 2003 1:17 am
Antipspambot question: 0
Location: United States
Contact:

re: New and Improved Lady Anne

Post by Eric » Fri Oct 13, 2006 2:41 pm

I have some odd shaped pieces of stainless and a little bit of free time coming up in a week or so. If I do build one I wont need cone patterns so dont worry lol :)

Since the intake is at the front the "splash" will be quite dramatic, Im thinking something like a nice dome cap will allow air to flow into the engine much better, otherwise they can kind of plug themselves up. The combustion volume would definately be larger and more uniform.

Maybe even make the intake go in at an angle so it is tangental to the dome to optimize flow and combustion charge shape.

Eric
Attachments
domeflow.GIF
domeflow.GIF (3.3 KiB) Viewed 7524 times
Image

Talking like a pirate does not qualify as experience, this should be common sense, as pirates have little real life experience in anything other than smelling bad, and contracting venereal diseases

Graham C. Williams
Posts: 571
Joined: Fri Oct 03, 2003 11:33 pm
Antipspambot question: 0
Location: England
Contact:

re: New and Improved Lady Anne

Post by Graham C. Williams » Fri Oct 13, 2006 7:25 pm

Eric,The motor as tested. NUDiS Format and UFLOW Format. The dims are ok but ignor the gas temps ect. If you have your own ideas about packing and unpacking motors into Chinese form go ahead.

Graham.
Attachments
FWEVIIIDIMS.jpg
(66.76 KiB) Downloaded 1262 times
testFWEVIII.jpg
(33.81 KiB) Downloaded 1246 times
FWEVIII.jpg
(50.64 KiB) Downloaded 1221 times

Eric
Posts: 1859
Joined: Sat Oct 04, 2003 1:17 am
Antipspambot question: 0
Location: United States
Contact:

re: New and Improved Lady Anne

Post by Eric » Sat Oct 14, 2006 3:49 am

There are a few ways to go about doing it, with different spots having various benifits from the acoustic standpoint, but I just like to optimize the actual gasflow mechanics, help the engine suck in as much air as it wants.

Very few models take any real flow into consideration, actual gas volumes with different temperatures and denisties flowing into eachother and interacting.

The fuel air charge shape is very important when you want to optimize an engine, if there is too much splashing going on there are pockets of dead air space that arent being filled to the max with a fresh air charge.

With the chinese valveless engine the air hits the bottom of the combustion chamber, splashes up around the wall and also continues forward and hits the combustion chamber cap where it also splashes out and some goes up into the top of the combustion chamber. When it ignites you can very clearly see this path and a large volume of dead space. With an optimized design the combustion chamber size can be reduced for a given power level, or produce more power by taking in more fuel and air and having a higher average density before ignition. The chinese makes up for it by having a good tailpipe design and longer cycle times because of the lengths involved so the splashes spread out farther and reduce dead space (but also reduce density), though it can also be made to produce quite a bit more power just by tweaking the flow to reduce pockets of dead space and maintain density.

I think with the regular conical cap style, and the intake right near the back, that the air is going to hit the wall and basically cause a road block in the flow. With a little bit deeper cap that is a dish you can benifit from the splash directing the air around better, and keeping the part of the intake near the front cap from becoming plugged so the air isnt trying to only get sucked into the engine around a basically flat 180 degree turn with massive resistance.

I suspect the engine would only get a portion of the fuel air charge that it would like in the alloted time. The intake should be in a position, and point in such a way that the largest volume of fuel air mixture can be sucked into the combustion chamber with ease.

If you have a longer engine splashing matters less and less, but if your shooting for the max from a fairly short engine I would look into optimizing the actual gas flow now that the acoustics are reasonably perfected. Things like flare geometry and the intake angle / position can make all the difference.

Well its late, Im tired and starting to ramble...

Eric
Image

Talking like a pirate does not qualify as experience, this should be common sense, as pirates have little real life experience in anything other than smelling bad, and contracting venereal diseases

Graham C. Williams
Posts: 571
Joined: Fri Oct 03, 2003 11:33 pm
Antipspambot question: 0
Location: England
Contact:

re: New and Improved Lady Anne

Post by Graham C. Williams » Sat Oct 14, 2006 11:26 am

Very interesting Eric. I had thought of it slightly differently. If I think of the Linear- motor from induction pipe to combustion zone as 3 areas; The induction pipe, the fuel injection / mixing zone and finally the combustion zone. Then apply this simplistic model to the Chinese. The induction pipe remains as is. The combustion zone is defined principally by the location of velocity and massflow minima. The mixing zone now becomes the diameter of the CC or some path at an angle to the axis of the motor, that is, instead mixing taking place in a region along the pipe (in The linear Example) it now takes place across the diameter of the pipe. The dead spots simply being regions where the local gas velocity are outside the allowable limits for combustion. I think we saw in one of the earlier ‘FWEChinese’ motors that the mixture looked as if it had been transported from the induction pipe to the front cone and back behind the induction pipe to the combustion zone. In other examples it looks as if the combustion zone is that bit of CC Wall opposite the induction pipe. These examples make me think that (for the Chinese motor) the final combustion zone is almost independent of the location of the mixing zone.

Graham.

Eric
Posts: 1859
Joined: Sat Oct 04, 2003 1:17 am
Antipspambot question: 0
Location: United States
Contact:

re: New and Improved Lady Anne

Post by Eric » Sat Oct 14, 2006 4:27 pm

Well at different parts of the cycle they can be distinct, but over the cycle the regions change.

With a good injector the mixing zone is greatly reduced, so that the flow going into the engine is ready to ignite. That increases burn speed because you dont have to wait for everything to mix, and faster burn speed results in higher pressure and more thrust.

The charge shape also affects burn time. With the linear intakes you can get extremely fast burn times because the charge is uniform and without dead air space, where the burn path would basically have to follow a maze of fuel air mixture since it doesnt want to jump the gaps. Dead air pockets increase the burn time, and reduce power.

In a well designed engine the ignition will occur from the tailpipe superheated gas, but also can happen from side wall ignition when the engine is hot. That is why many engines that arent quite right can self sustain after a warm up period once they are red hot.

Now when you have the fuel air mass shaped in such a way where the sidewall and tailpipe gas ignition happens almost simultaneously, the fuel charge ignites from multiple points. In the case of the linear, from the entire side of the combustion chamber. The fuel air charge burns from back to front and from outside in simultaneously, the burn speed is very rapid, and with no dead air spaces there is the highest potential for maximum thrust and fuel efficiency.

With the linear engine the fuel air mixture wants to get pulled right in, with the chinese it is also a fairly straight shot for the air to make, in order to fill the largest volume of the combustion chamber before ignition, with the intake going in at a shallow forward angle directly into the cap, I fear the resistance would require a larger diameter intake tube in order to pull air in effectively enough to get a decent charge before either tailpipe or sidewall ignition occurs.

In the simple schematic the green area represents the area of highest fuel-air density.

When you just look down the tailpipe of the engine the flame looks pretty uniform because your looking through such a long length of burning material.

If you make a window into the side of the combustion chamber you see exactly what is burning and what isnt, and the exact shape.

It happens too fast to see individual cycles with small engines, but larger ones you can start to see single cycle characteristics. With the smaller engines the burn path will just look like a solid path of constant flame surrounded by dead air space that isnt emitting any light.

Eric
Attachments
burnpathgif.GIF
burnpathgif.GIF (6.91 KiB) Viewed 7394 times
Image

Talking like a pirate does not qualify as experience, this should be common sense, as pirates have little real life experience in anything other than smelling bad, and contracting venereal diseases

Mark
Posts: 10684
Joined: Sat Oct 11, 2003 10:14 pm

re: New and Improved Lady Anne

Post by Mark » Mon Oct 16, 2006 11:42 pm

I remember in some literature cigar shapes are bad news for wave propagation, that is narrow going to wide and then back again to narrow. But who knows.
Mark
Presentation is Everything

larry cottrill
Posts: 4140
Joined: Sun Oct 05, 2003 1:17 am
Antipspambot question: 0
Location: Mingo, Iowa USA
Contact:

New and Improved Lady Anne REV 03

Post by larry cottrill » Tue Nov 21, 2006 8:30 pm

Here is a new front end design with "low profile" intake. This is very easy to build - I'm putting together a couple of these for experimental use.

All the cone dimensions are exactly the same as the Rev 02 Lady Anne, except for the big breathing port cut into the front edge of the chamber cone. The intake is cut out and formed BEFORE cutting the two V-shaped notches in the sides (I learned this the hard way ;-) - once it is bent to shape and flared, cut the two notches in and bend down on the fold line to close the notches. When you weld it onto the cone, adjust so the nose of the intake shell meets up with the dome edge and tack weld it there. THEN, butt weld the notches up the sides. Finally, after the intake side edges are fully welded to the chamber cone, heat and gently hammer the remainder of the intake front edge down flush with the dome edge and weld all the way across. Nothing to it.

As usual, all the drawings given here will print full size on 8.5 x 11 inch paper using a 96 DPI printer.

L Cottrill
Attachments
FWE_VIII_Lady_Anne_Rev03_full_size_A.gif
The Lady Anne Boleyn Rev 03 Full Size Plan (front end). All other dimensions same as the Rev 02 layout. Drawing Copyright 2006 Larry Cottrill
(26.82 KiB) Downloaded 1158 times
Lady_Anne_Rev03_intake_sheet.gif
The Lady Anne Rev 03 Intake Sheet Pattern. Drawing Copyright 2006 Larry Cottrill
Lady_Anne_Rev03_intake_sheet.gif (11.1 KiB) Viewed 6862 times
Lady_Anne_Rev03_cone_sheet_1.gif
Lady Anne Rev 03 Chamber Cone Sheet Pattern; standard FWE dome pattern also included. Drawing Copyright 2006 Larry Cottrill
(19.94 KiB) Downloaded 1175 times
FWE_VIII_Lady_Anne_Rev03_full_size_sections.gif
Lady Anne Rev 03 Full Size Sections, as referenced on the front end plan drawing. Drawing Copyright 2006 Larry Cottrill
FWE_VIII_Lady_Anne_Rev03_full_size_sections.gif (17.2 KiB) Viewed 6859 times

Graham C. Williams
Posts: 571
Joined: Fri Oct 03, 2003 11:33 pm
Antipspambot question: 0
Location: England
Contact:

re: New and Improved Lady Anne

Post by Graham C. Williams » Wed Nov 22, 2006 12:03 am

Dear Larry.
If you get the NUDiS programme up and running (See Tools) send me an email. I'll send you the model and full combustion run for this motor.

Regards
Graham.

James D
Posts: 86
Joined: Sun Jan 16, 2005 9:14 pm
Antipspambot question: 0
Location: England

re: New and Improved Lady Anne

Post by James D » Sun Nov 26, 2006 5:50 pm

Larry and all,

I built 'Anne Boleyn Rev 02' a few weeks ago and unfortunately I've not been able to get it to run (on propane). I tried just about every position for the fuel pipe within the intake and several different types of injector including the normal straight pipe, a radial drilled stinger and a Rosscojector; however it never really seemed close to proper running.
The nearest I got was a pretty loud resonant howling mode but it heated up the whole duct somewhat uniformly, and wouldn't sustain without forced air, so I think it was just acting like a blowtorch.

I will not be able to re-test it any time soon but I'd like to hear anyone's thoughts on what could be wrong. The intake configuration seems pretty unconventional, isn't the position where the intake joins the combustion chamber a displacement node, or should this duct have a more linear character?
Attachments
AnneBoleynRev02_small.jpg
(19.61 KiB) Downloaded 1240 times

Post Reply