lukenz
Member
Joined: October 2018
Posts: 38
|
Post by lukenz on Mar 11, 2019 5:11:05 GMT -5
Hi Luke Sorry about the delay . If you intend running on kero maybe replace all those small holes in the two rows of Primary holes with a single row of larger diameter holes on your dotted "spray" line , spaced/positioned longtitudenly "between" your Secondary holes Cheers John Hi John, Apologies, my previous post reads a bit blunt now I read it back. I also notice all three of my CAD drawings are the same, forgot to drag the port to my other two designs in drawings 2 & 3 whoops! Perfect thanks for the advice John, would I make them 10mm like the others or whatever bigger size divides into the primary hole area but with the correct amount of holes to align longitudinally in between the gaps of the secondary holes? Just for educational purposes, what does spacing them longitudinally in the gaps of the secondary holes do? Regards, Luke |
|
|
|
Post by racket on Mar 11, 2019 16:04:03 GMT -5
Hi Luke
Whatever size gives you the same area and correct number of holes.
Displacing them "half way" provides an opportunity for extra turbulence
Cheers
John
|
|
lukenz
Member
Joined: October 2018
Posts: 38
|
Post by lukenz on Mar 24, 2019 5:16:12 GMT -5
Cheers for that John, just waiting for my colleague to weld up my stainless components so I can get on with this project. Also, is it ok to have a 90deg bend coming off the end of my combustion chamber into the exhaust turbine flange? I want my turbo to lie parallel with the combustion chamber to save space? Would this cost me anything in efficiency/performance?
Have also ordered lots of goodies from eBay etc for the build, including an electric starter. Will post some pictures up soon after moving house.
Luke
|
|
|
|
Post by racket on Mar 24, 2019 16:30:41 GMT -5
Hi Luke
The 90 degree bend isn't the best setup but as long as you make the bend with a reasonable radius and have the diameter of the tube as large as possible to keep gas velocity down, you shouldn't lose much.
Cheers
John
|
|
lukenz
Member
Joined: October 2018
Posts: 38
|
Post by lukenz on Mar 25, 2019 5:23:04 GMT -5
Hi Luke The 90 degree bend isn't the best setup but as long as you make the bend with a reasonable radius and have the diameter of the tube as large as possible to keep gas velocity down, you shouldn't lose much. Cheers John Hi John, Got it thanks! I’m guessing a long radius bend preferably over a short radius? Does increasing the gas velocity cause turbine over speed? Or is it simply an efficiency loss? Cheers, Luke |
|
|
|
Post by racket on Mar 25, 2019 16:01:33 GMT -5
Hi Luke
The gas velocity increase is done within the scroll nozzle , as the scroll A/R is reduced generally the gas speed increases .
A large radius bend with a cross section larger than the scroll inlet area reduces the potential for unfavourable turbulence within the bend that can create losses.
Turbine overspeed generally has more to do with overfueling .
Cheers
John
|
|
lukenz
Member
Joined: October 2018
Posts: 38
|
Post by lukenz on Mar 28, 2019 14:50:14 GMT -5
Hi Luke The gas velocity increase is done within the scroll nozzle , as the scroll A/R is reduced generally the gas speed increases . A large radius bend with a cross section larger than the scroll inlet area reduces the potential for unfavourable turbulence within the bend that can create losses. Turbine overspeed generally has more to do with overfueling . Cheers John Thanks John for your help! What fuel pump do you guys use? I’m guessing it all has to do with the map for my turbo which then dictates the fuel pressure required? |
|
|
|
Post by racket on Mar 28, 2019 16:32:52 GMT -5
EFI pump
|
|
|
|
Post by smithy1 on Mar 28, 2019 19:18:04 GMT -5
What John said, a normal EFI pump is fine for vaporizer type setups, but if you go to a single injector, you'll probably need higher pressures to get decent atomization.
I have an aircraft fuel injector in my machine and it requires well in excess of 500psi at full noise. The pump I have is quite capable of well over 3000psi..😮
Smithy.
|
|
lukenz
Member
Joined: October 2018
Posts: 38
|
Post by lukenz on Mar 29, 2019 5:06:59 GMT -5
What John said, a normal EFI pump is fine for vaporizer type setups, but if you go to a single injector, you'll probably need higher pressures to get decent atomization. I have an aircraft fuel injector in my machine and it requires well in excess of 500psi at full noise. The pump I have is quite capable of well over 3000psi..😮 Smithy. Thanks John & Smithy. I have a single atomising spray nozzle so will source a typical EFI inline pump, walbro etc. or will that even be excessive? Do you run a ball/needle valve for engine speed with a relief valve before the the valve that vents back to tank? Whoa that’s a whole lot of pressure! Up there with he hydraulic pumps we service in the hydraulic industry I work in 😲 |
|
|
|
Post by smithy1 on Mar 31, 2019 18:50:32 GMT -5
Some of the better EFI pumps will see you out of trouble. You need to remember the pump needs to produce enough pressure and flow above the P2 pressure, or you'll struggle to get good atomization.
Smithy.
|
|
lukenz
Member
Joined: October 2018
Posts: 38
|
Post by lukenz on Aug 5, 2019 5:11:30 GMT -5
So it has been a while since I have posted, life's busy! But so is jet engine progress  It seems the most recent discussion we had was what fuel pump I should be using, I ended up purchasing a Walbro 255LPH in-line pump. So currently my engine is awaiting a colleague to tig weld all the stainless. Have a look at some images attached to see the progress I have made:     I have also been doing a bit of lathe work to fit the starter motor to the engine. I will initially use workshop air or a blower to test run, but eventually will aim to have this self starting:   Other components that I have acquired are (some not in below image): 2x Thermocouples 1x Oil Pump 1x Fuel Pump 2x Temp Gauges 1x Tachometre & Sensor  Thanks for having patience with this build and all the input so far. Luke |
|
lukenz
Member
Joined: October 2018
Posts: 38
|
Post by lukenz on Aug 13, 2019 5:25:18 GMT -5
Hey guys, at what point are you tapping into the combustion chamber for your P2 sensor? I was expecting to place it on my outlet pipe to the exhaust turbine but battling in my mind what type of pressure sensor would handle the levels of heat at this point, is the outer combustor housing a better place or even the diffuser between the compressor housing and combustion chamber?
Kind regards,
Luke
|
|
BFTO
Veteran Member
Joined: February 2016
Posts: 128 
|
Post by BFTO on Aug 13, 2019 6:32:29 GMT -5
|
|
lukenz
Member
Joined: October 2018
Posts: 38
|
Post by lukenz on Aug 13, 2019 15:01:19 GMT -5
|
|
