HX 82 102/255 " Money Pit "

[racket]

Hi Andy

Very nice to see 40psi on the P2 gauge :-)

Another step forward .

Cheers
John

[Deleted]

Hi every one.... so have been wanting to do another test, but the weather in UK has not been helping. I think its rain 6 out of the last 7

So to keep be busy i have been working on some thing, or perhaps the next stage you could say......


Can any one guess what the plan is for these ?





All The Best

Andy

[turboron]

Andy, now you have us quivering with anticipation.

Thanks, Ron

[racket]

Hi Andy

LOL.............you been looking for some "balls" before doing the afterburner test ?? ;-)

Cheers
John

[Deleted]

Jun 13, 2019 17:04:02 GMT -5 racket said:

Hi Andy

LOL.............you been looking for some "balls" before doing the afterburner test ?? ;-)

Cheers
John

there is that.... but am still looking for some dry weather as well... day 7 and still raining and still not looking good for a few days


Chat soon

Andy

[Deleted]

Hi every one, so after a week of waiting for it to stop raining.....😟I got the engine test done, with the afterburn bolted on. The results are mixed.... all good, but some working out to do. Hope you enjoy

[racket]

Hi Andy

Another milestone passed , you're knocking them over , just some fuel to the A/B to go :-)

Cheers
John

[Deleted]

[Sweetenough]

Hi Andy,
Have been following your build with great interest!
Fantastic build! Been wondering when the power turbine would be introduced :-)
Have been thinking of upgrading my afterburner to next season and have been spying on your design.
Have a couple of questions.....
Where do you place the turbine exhaust thermocouple?
The fuel ring in the original "design" should it spray towards the turbine wheel or spray along with the exhaust flow?
Your new and improved design sure looks beautiful and difficult to fabricate :-)
Is the purpose to induce some drag behind it for better fuel mixing? (My hillbilly understanding is if it was placed the other way around it would create less drag and pressure loss)
How many holes and what size are you aiming for?
Kind Regards
Thomas

[Deleted]

Jun 18, 2019 7:45:12 GMT -5 Sweetenough said:

Hi Andy,
Have been following your build with great interest!
Fantastic build! Been wondering when the power turbine would be introduced :-)
Have been thinking of upgrading my afterburner to next season and have been spying on your design.
Have a couple of questions.....
Where do you place the turbine exhaust thermocouple?
The fuel ring in the original "design" should it spray towards the turbine wheel or spray along with the exhaust flow?
Your new and improved design sure looks beautiful and difficult to fabricate :-)
Is the purpose to induce some drag behind it for better fuel mixing? (My hillbilly understanding is if it was placed the other way around it would create less drag and pressure loss)
How many holes and what size are you aiming for?
Kind Regards
Thomas

Ideally you want the etg thermocuple as close to the turbine wheel as possible and perhaps sticking in 15 to 20 mm.... once you in stall the fuel rail for the after burner, try and avoid placement so fuel dont hit
the thermocuple

The fuel should spray towards the turbine wheel. I think you should stick to 8x2 mm holes in the fuel rail. I will be having 24 x 1 mm holes and may be more, still some maths to do. You can have to much fuel going into an afterburner

It helps a lot having laser cut parts, and admitting you can not do it all your self. I have a good friend who welds things for me.... can not risk the afterburner bursting because of my bad welding . The castle end to the dump tube is i hope improves mixing, the edge in affect is longer, more area to mix and perhaps a difference in pressure drop points


Hope its some help

[Sweetenough]

Thanks for the answers Andy,
Like the castle end, really good idea!
What do you think of making the inner pipe from the turbo exhaust to the " castle" to a slight opening cone shape? To act as as diffuser and slightly lower the turbine outlet pressure?
Will probably not do much but could perhaps improve performance a notch.
Started to think about different fuel ring designs but the fabrication is for sure the challenge.
And to get it installed with fuel supply inside of the pipe also require some thought.
Looking forward to hear your afterburner roar soon!
Kind regards
Thomas

[racket]

Hi Andy and Thomas

Heres a Post I did when doing my A/B for the GT6041 ..............

I'm currently up to the stage of constructing the fuel injection system for the karts A/B , .................. due to the design of the A/B my thermocouples for TOT measurement are displaced to the outlet of the diffuser , and to prevent fuel spray from contacting the thermocouples I needed to determine the axial distance between the spray ring and thermocouples to minimise "wasted" A/B length .

The engine will require ~4 litres/min of fuel to the A/B ,................... with 20 spray orifii , thats ~200 cc/hole/min .

A test rig was manufactured using a short "blind ended" length of the same 3/8" OD stainless tubing as the fuel ring is constructed from and a single 0.7mm hole was drilled in its side , the tubing was then pressed into a fitting that was screwed onto a garden tap .

When water pressure was applied to the test rig it squirted horizontally ~10 feet at the required 200ml/min flow through the 0.7mm oriface , this was much further than expected :-(( ........................but upon application of the leafblower to simulate the gases exiting the turb exducer , the jet of water was reduced to ~2 - 3 inches before it disintergrated into a spray going "backwards .

This was still a considerable axial distance so I opened up the hole to 1.0mm diameter , this increases flow area by about 2 times , so a decision to reduce the number of holes in the A/B sprayer to 16 was made , this would now require a flow of ~250ml/hole/minute , ....................this produced a horizontal jet of ~6 feet when the test rig was fitted to the garden tap .

The leafblower reduced the axial squirt to between 1 and 2 inches ................getting more like it :-)

There was one unfortunate side effect of having a squirt of fuel going axially towards the imaginary turb wheel exducer's gas flow and that was that some of the "fuel/water" was blown straight back onto the spray ring where it flowed around to the downstream side of the tubing and was blown off in large droplets , not the best thing for fast combustion :-(

I then tried "offsetting" the fuel to gas flow ,.......... this dramatically affected the outcome by not only shortening the fuel squirt length ( to<1 inch ) compared to a "head on " approach but also blew the fuel spray to the side of the tubing in a well broken up spray without any large droplets .

It only required an "offset" of ~15 degrees between fuel squirt and gas flow for this to occur , this should easily be accomplished by drilling the 16 X 1.0mm dia holes in a staggered pattern slightly to each side of the centreline of the spray ring , the centreline of my spray ring is ~90 mm diameter , the A/B crossectional area "outside" the sprayring should be roughly equal to that inside the ring, allowing for a cooling airflow along the inside of the A/B wall , I want more fuel in the "centre" than near the "outside" to keep wall temps down .

Time to start drilling holes :-).......................

I'm not certain that holes drilled directly at the wheel ( axially) will produce the best atomisation overall ..................thoughts please .

Cheers
John

[Sweetenough]

Hi,
Thanks John! Really good information and interesting tests!
Sorry for high-jacking your build thread with my build questions Andy.....
Will continue with more questions on my thread for the B&W S500 Jetoped instead.

Kind Regards
Thomas

[Deleted]

So things did not go to plan, but afterburner wants to light, but ideal set to high, and need more fuel, oil pressure dropped easy fix

[racket]

Hi Andy

Nics pops and bangs .......it'd sound "heavy calibre" ;-)

Very close to running .

The temp and pressures gauges reading ~112 and 3 psi , are they T2 temp rise across the comp and jetpipe total pressures at 25 psi P2 ??

Kart is looking good , LOL....just need some wheels and you'll be mobile .

Cheers
John