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Post by azwood on Jan 22, 2021 17:25:20 GMT -5
That's a nice action on the pwm peddle
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Post by azwood on Jan 22, 2021 17:27:02 GMT -5
I don't know anything about nozzles because I used evap tubes the pwm seems to work well that way
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Post by racket on Jan 22, 2021 17:37:42 GMT -5
The Variflo will act as a normal nozzle , no need to change it
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Post by azwood on Jan 22, 2021 19:12:25 GMT -5
Just wait antil you wife see's what your using her vase for lol I'm always getting in trouble for using kitchen stuff in the shed.
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ausjet
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Post by ausjet on Jan 23, 2021 4:05:57 GMT -5
Just wait antil you wife see's what your using her vase for lol I'm always getting in trouble for using kitchen stuff in the shed. Hahahah I got her actuating the throttle in one of the vids whilst I filmed. Yeh she wasn’t impressed when she saw it. I thought it was the perfect jug for the job 😂 |
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Post by slittlewing on Jan 24, 2021 3:43:54 GMT -5
😂😂 hahaha I got in trouble for using the kitchen “mixing bowl” for wet sanding, it got so dirty that I ended up keeping it as a permanent garage tool 😁
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ausjet
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Post by ausjet on Jan 24, 2021 5:19:03 GMT -5
😂😂 hahaha I got in trouble for using the kitchen “mixing bowl” for wet sanding, it got so dirty that I ended up keeping it as a permanent garage tool 😁 You only get in trouble once then you can use it over and over 😂 |
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ausjet
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Post by ausjet on Feb 15, 2021 2:23:36 GMT -5
Here’s a few progress shots of the kart so far. I added an adjustable check valve to the fuel supply line in case the shutoff is ever used. Don’t want to dead head it and blow a line.    I’m trying to pre-empt a few things here, what have you guys experienced in regards to the following.. —Im not sure if the distance between the afterburner spray ring and TOT probe (30mm) is too close.. I don’t want the fuel spray to hit the probe when running and give false readings. —Have you guys needed to run your afterburner Bosch 044 at higher voltages than 12? Or is “tuning”(enlarging) of the spray ring hole size sufficient. If it could be a problem with this size engine I’ll try and setup some sort of 24v and pwm feed to the pump now rather than later.  Cheers guys |
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Post by racket on Feb 15, 2021 3:27:43 GMT -5
Hi
This might help , it was from when I was having the same queries ...............
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 .........................
As for the fuel pump flow vs voltage , Smithy did some very accurate flow tests on an 044 clone at voltages between 12 and 18V , and at 40 psi and 18V it flowed 430 lbs/HR of fuel .
With your 98 mm inducer you'll flow ~2.3 lbs/s of air , 138 lbs/min , assuming 30% of that is "burnt" in the flametube , that leaves ~97 lbs/min to be burnt in the A/B , 97/min = 5820 lbs/hr , divide by 15 = 388 lbs/hr of fuel for the A/B .
You just need to adjust the A/B fuel ring hole area so as to require that ~40 psi and a flow of ~6.5 lbs/min - 3.8 lpm
Hope this helps
Cheers
John
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ausjet
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Post by ausjet on Feb 15, 2021 4:39:10 GMT -5
Thats some extensive r&d! Thanks for that info John. Never thought the offsetting would make such a difference in distance sprayed👌🏻 sweet, safe as is.
I’ll mount the thermocouple and spray ring as picture and aim for those flow/pressure numbers.
Keith
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Post by smithy1 on Feb 18, 2021 0:45:45 GMT -5
Thats some extensive r&d! Thanks for that info John. Never thought the offsetting would make such a difference in distance sprayed👌🏻 sweet, safe as is. I’ll mount the thermocouple and spray ring as picture and aim for those flow/pressure numbers. Keith Hi Keith, Nice looking kart you have there....Here's a pic of mine for reference..  John was instrumental in the building of this kart...all I did was fettle it a bit... Smithy. |
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ausjet
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Post by ausjet on Feb 18, 2021 3:21:57 GMT -5
Thats some extensive r&d! Thanks for that info John. Never thought the offsetting would make such a difference in distance sprayed👌🏻 sweet, safe as is. I’ll mount the thermocouple and spray ring as picture and aim for those flow/pressure numbers. Keith Hi Keith, Nice looking kart you have there....Here's a pic of mine for reference.. John was instrumental in the building of this kart...all I did was fettle it a bit... Smithy. Cheers smithy, glad I’m not the only one with a turbo that close to the seat. No mullets allowed 😂 did you make the front fairing? Looks great. Do you take it out much? I think you said a while ago you took it to a few car shows doing demos? |
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Post by smithy1 on Feb 24, 2021 19:58:30 GMT -5
Hi Keith, Nice looking kart you have there....Here's a pic of mine for reference.. John was instrumental in the building of this kart...all I did was fettle it a bit... Smithy. Cheers smithy, glad I’m not the only one with a turbo that close to the seat. No mullets allowed 😂 did you make the front fairing? Looks great. Do you take it out much? I think you said a while ago you took it to a few car shows doing demos? Front fairings came with it...I believe it used to be a "Shifter Kart" and has front brakes as well as the single rear brake. I only do car shows with it these days as all the race tracks etc...wont allow such a vehicle on their tracks as it doesn't meet their "safety standards". My local drag strip wants a roll cage, 5 point harness, parachute and manual fuel shut-off etc etc... Cheers, Smithy. |
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Post by turboron on Feb 25, 2021 8:04:21 GMT -5
sltillewing, how are you attaching the bypass fuel nozzle to the combustor dome. The Delevan and Monarch bypass fuel flow nozzle adapters I see online do not have threads on the outside diameter. It looks like you must braze a threaded adapter to the bypass valve adapter or directly braze the adapter to the combustor dome. How did you attach the bypass adapter to your dome? Pictures please.
Thanks, Ron
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ausjet
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Post by ausjet on Feb 26, 2021 4:22:08 GMT -5
sltillewing, how are you attaching the bypass fuel nozzle to the combustor dome. The Delevan and Monarch bypass fuel flow nozzle adapters I see online do not have threads on the outside diameter. It looks like you must braze a threaded adapter to the bypass valve adapter or directly braze the adapter to the combustor dome. How did you attach the bypass adapter to your dome? Pictures please. Thanks, Ron Hi Ron, The standard extinguisher dome end has a metric thread on it so found a plug from a hydraulic supplier with the same external thread then drilled and tapped the adaptor into the centre of it. Serves as the nozzle holder and flame tube end mount in the 1 part.    |
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