76/86 Turbojet

[racket]

Hi Stephan

Yep , thats getting closer , :-)

.............. maybe have the springs on the edge of the flametube endcap rather than offset on mounts which might distort the flametube side wall if it gets very hot .

The fuel delivery tube will need to be a semi coil (maybe 270 degrees of a circle) rather than straight so as to allow for expansionary changes , this extra length of tube inside the combustor will make it easier to construct/assemble.

Swirlers are good , its possible to purchase ready made swirlers for small oil burners , checkout a oilburner spray nozzle supplier for bits, the endcap on my first turbine bikes flametube used a ready made swirler as well as a large number of small holes in the endcap .

Happy building :-)

Cheers
John

[stoffe64]

hello John!
sounds nice about that ready made swirlers,have to look around for them then, what do you think about the idea to put a glowplug in there as well? connected to the flametube lid??
material of that fuel line in there?,stainless or what??,i intend to use a hydraulic micro aggregate with say up to 100 bar pressure in hope to get very nice atomisation for good burn!
maybe stainless then?
cheers/stephan

[racket]

Hi Stephan

If you use a spray nozzle the actual position for the glowplug would need to be somewhere down the side of the flametube where the spray would be passing by , there might not be much atomised fuel near the outercan lid area .

I use bundy tube , its what automotive brake lines are made of , comes in 3/16" - 5mm and 1/4"- 6.5mm OD sizes, its in an annealed state when purchased so its easy to get nice tight bends ....................stainless can become brittle over time , but does look better :-)

Bundy tube has a lot of different fittings available for it and would be more than up to the job , easily sourced from brake and clutch repair shops .

Cheers
John

[stoffe64]

thanks John!

really appreciate all your help, will start to look around for brake lines and fittings then and other suitable bits and pieces when the build advances to that point, first general combustor build on the way now
cheers/stephan

[stoffe64]

i have been thinking about fuel nozzles, and i can not find anything suitable right off , i plan to use this hydraulic micro aggregate unit capable of delivering a healthy for the engine(lethal to us) 100 bar pressure, but the nozzles i have found does not take such pressures, i have understood that i should use about 12gph ,hollow cone with about 60-90 degrees angle,preferably stainless ones i guess to survive the hot environment, now i ask you guys in here for any hints regarding nozzles suitable for the job with such high pressures for very good atomization, this is one of the points with my engine build that i strive for, very good atomization for good clean burn.
cheers/stephan

[racket]

Hi Stephan

I used Steiner hollow cone stainless nozzle up to ~90 bar , they can go to ~200 bar .


www.steinen.com/oil-burner/usa/english/standard-nozzles.php

Theres no need to go past ~40 - 50 bar for good atomisation , flow goes up as the square root of pressure , 50bar - 750 psi has sq rt of 27.38 , 100 bar-1500 psi has sq root of 38.72 , so there will only be a 41% increase in flow even though pressure has gone up by 50 bar .

Cheers
John

[stoffe64]

YES, i understand john but the hydraulic unit i have gives me 100 bar pressure,that is with hydraulic oil ofcourse,i dont tested it with jetfuel yet but i think it should be around 100 bar+- 10-20 bar maybe, i dont know really but it should be enough, you think i should add a pressure relief valve in there John?
cheers/stephan

[Richard OConnell]

You mean like a regulated fuel bypass?

[stoffe64]

YES,sort of Richard, so you have a constant max allowable pressure of 50 bar but then again you need another controller for the throttle of the engine because maxspeed would be when you had that 50 bar at the nozzle, that you can not have at idle speed!
cheers/stephan

[racket]

Hi Stephan

With my 50 bar system on the bike I used a pressure relief valve to set the max fuel flow rate .

There was a pressure differential relief valve in the system so as to maintain a constant pressure drop across the throttle metering oriface which was a small hydraulic needle valve that had a arm on the spindle connected via cable to the throttle twistgrip on the handlebars .

Cheers
John

[turbochris]

I like lower fuel pressure as P2 rise helps cut back effective flow, helps stabilize rpm somewhat. Also Hago BPS nozzles work great, lit them off w a single space heater spark plug w extended electrodes.

[stoffe64]

Hmm,what Can i say.?
The projekt starts to come to a halt
Reason is that it is time to start wel soon,atleast to start fabricating the combustor parts
And stainless you should Tig weld or maybe arc weld with stainless rod
I got my tax Money so i started to look for such welder, wife bought a brand New camera with equipment, the i get welding equipment for my project i thought, NO WAY chosee Shell Said
Yeeeez,One gets frustrated.

[racket]

Hi Stephan

LOL......frustration is part of turbine engine construction, it took me several years to get my first one built, hang in there :-)

Cheers
John

[stoffe64]

Im trying John.....

[stoffe64]

oil pump and oil filter assembly bracket completed as well as oil inlet line to turbo finished!
still wondering, changing setup, design, redesign changing again of the combustor build due to the fact that it MUST be simple because i dont own any TIG equipment, dont know anyone with such Equipment living Close to uppsala either, so it MUST be simple to make, the same thing with the nice oil tanks, have to abandon that idea because of welding Stainless!!
now have other ideas of that area BUT still soon it comes to a major hault when things have to be TIG welded
cheers/stephan