CH3NO2
Senior Member
Joined: March 2017
Posts: 455
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Post by CH3NO2 on Dec 15, 2017 16:49:29 GMT -5
Very nice setup Tommy. I love your use of diffusers.
Are you running main or auxiliary fuel injectors around the circumference of zone 1?
Tony
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Post by racket on Dec 15, 2017 17:20:34 GMT -5
Looking good guys , beautifully finished machine .
LOL...............all that snow around in the vid almost cooled me down , its a hot humid morning here and 23 Degrees C at 9 am , I should send you some sunshine ;-)
Cheers John
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BFTO
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Joined: February 2016
Posts: 128
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Post by BFTO on Dec 15, 2017 18:11:50 GMT -5
Thanx all! next thing is to get the AB screaming, after that..maybe a power turbine Very nice setup Tommy. I love your use of diffusers. Are you running main or auxiliary fuel injectors around the circumference of zone 1? Tony Hi Tony Dont understand the question But we have a propane injector (radial holes) in the middle of the primary zone to start the engine and warm the evaporators. For main fuel, diesel/gasoline (80/20 mix) is squirted inside the evaporators through 0,7mm syringes. You can probably look at pictures in the beginning of this build and see how its made. Looking good guys , beautifully finished machine . LOL...............all that snow around in the vid almost cooled me down , its a hot humid morning here and 23 Degrees C at 9 am , I should send you some sunshine ;-) Cheers John
Not much snow when the last video was taken, now we have 3-4dm and climbing -11degC right now, i like -11 more than +23deg
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CH3NO2
Senior Member
Joined: March 2017
Posts: 455
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Post by CH3NO2 on Dec 15, 2017 21:24:16 GMT -5
Hi Tommy,
OK, so they are for the propane pre-heat. A very refined build and clean.
Will you use the system for sled propulsion?
Tony
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Post by jetjeff on Dec 16, 2017 14:39:26 GMT -5
Nice work,,,I could use ETE-1 to melt the 10" of snow I already have.
Regards
Jeff
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BFTO
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Posts: 128
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Post by BFTO on Dec 16, 2017 16:16:15 GMT -5
Hi Tommy, OK, so they are for the propane pre-heat. A very refined build and clean. Will you use the system for sled propulsion? Tony Haven't decide yet what we will do with the engine, maybe a power turbine and mount on something fun. I have some big plans for the future with a turboshaft car or boat that I want to put my resources in, time will tell. We did mount the ignition today with sucess, it light of the propane. It was so cold that the needle on the oil pressure was maxed out (10bar), after adjusting the pressure she started right up. When we introduced the fuel after maybe 30sec of idling on propane she smoked ALOT, the same amount of smoke as if we introduced fuel to the AB without ignite it. We did run for 20sec maybe before our battery begin to drop voltage and we cut fuel because oil pump begin to lose rpms. Our teory on why she smoked like that is that the evaporators was probably not up to the temps we want on the short idling. Next time we will idle longer and have a fully charged battery, then the AB will scream.
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Post by Johansson on Dec 16, 2017 16:41:42 GMT -5
That is a bit odd, usually it only takes 10 seconds or so of preheat with propane before the engine can be switched over to liquid fuel. Could it be that your propane idling is causing the flame zone to be so far down the combustor that it isn´t heating the evaps at all? I haven´t read the entire build thread lately so I don´t remember how the propane injector system is set up, but the best way is to inject it into the evaps so the propane has time to mix with air before entering the primary zone. On our jet kick combustors we just dump the propane into the top of the combustor and it has been causing us trouble since the propane flame won´t stay in the primary zone but seems to take a cigar shape and reach all the way down to the turbine scroll, not good since the scrolls get massive heat and on one engine the dividing wall has started to melt from a prolonged preheat... Cheers! /Anders
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BFTO
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Joined: February 2016
Posts: 128
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Post by BFTO on Dec 16, 2017 17:42:56 GMT -5
That is a bit odd, usually it only takes 10 seconds or so of preheat with propane before the engine can be switched over to liquid fuel. Could it be that your propane idling is causing the flame zone to be so far down the combustor that it isn´t heating the evaps at all? I haven´t read the entire build thread lately so I don´t remember how the propane injector system is set up, but the best way is to inject it into the evaps so the propane has time to mix with air before entering the primary zone. On our jet kick combustors we just dump the propane into the top of the combustor and it has been causing us trouble since the propane flame won´t stay in the primary zone but seems to take a cigar shape and reach all the way down to the turbine scroll, not good since the scrolls get massive heat and on one engine the dividing wall has started to melt from a prolonged preheat... Cheers! /Anders We did run it on liquid fuel for 20sec before the voltage drop and cut off the fuel so the evaps should be kinda hot but the fuel pressure was a little bit more than it usally are on idling. Probably some of the fuel was drippling down the flametube and cause the smoke. Our propane is injected in the top of combustor in the primary zone, our TIT temps isnt that high during preheat. But probably we only need to prolong the preheat, last weekend we did preheat 2-3min and it worked fine. It is alot of steel to get warm, our evaps is 2mm thick and the fuel was -10degC. But yes, for optimal preheat the propane should be injected into the evaps but it feels a bit overly complex to make it happen.
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Post by Johansson on Dec 17, 2017 2:30:18 GMT -5
Ahh the curse of thick walled evaps! Then I understand why you need so much heat.
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BFTO
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Joined: February 2016
Posts: 128
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Post by BFTO on Jan 8, 2018 2:59:10 GMT -5
Installed T2 probe this weekend, idle on propane for 1min and then diesel without any problem. The AB light for 1sec but had problem with the cheap potentiometer on the AB pump so we made a huge smoke show, have ordered a better one. We ran out of diesel before higher power setting, 12$ of diesel in 2min . Next weekend we will install the potensiometer and flowtest the AB fuel supply. Running 45degC colder on 1bar now then before all small changes. P2 = 0,5Bar P2 = 1Bar T2 = 26 C T2 = 69 C T1 = -4 C T1 = -4 C TOT = 412 C TOT = 450 C
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Post by racket on Jan 8, 2018 4:32:22 GMT -5
Hi
Your P2 0.5 bar temp readings are "not computing" , the T2 needs to at least 10 degrees higher , current comp efficiency is an impossible 110% .
The 1.0 Bar readings are "better" with comp effic ~80%
TOTs are very low , plenty of room to increase those with the A/B activated
Cheers John
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BFTO
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Post by BFTO on Jan 8, 2018 5:56:12 GMT -5
Hi Your P2 0.5 bar temp readings are "not computing" , the T2 needs to at least 10 degrees higher , current comp efficiency is an impossible 110% . The 1.0 Bar readings are "better" with comp effic ~80% TOTs are very low , plenty of room to increase those with the A/B activated Cheers John Yea the temps at 0,5bar was confusing me to, tested the new T2 probe with a IR-gun and was within a deg C difference in the garage??. Maybe the K-probe is slow to change temps, we was at 0,5bar for maybe 30sec. Cant wait to see what comp eff we get at a little bit higher power settings next time
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BFTO
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Joined: February 2016
Posts: 128
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Post by BFTO on May 13, 2018 12:03:37 GMT -5
Made some changes to the AB fuel supply today, valve instead of PWM. Tested 1,5Bar P2 without AB and was running without problem. Will post the T2/P2/EGT later when reviewed the video. The AB was hard to ignite, we need to go down to 0,5bar P2 to make it light with the spark plug. Fuel flow to the AB was around 1,2-1,5L/min and was burning really well with no smoke or flame, the AB was glowning red after a few minutes. When we throttle up to above 0,7bar P2 the AB was blown out with a few low pitch noise of an unstable flame, probably we need to add some other type of flame holder? I am thinking of a couple of split tubes of heat resistence mtrl, will probably make it easier to ignite aswell. A successful day! will post Videos/pictures later.
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BFTO
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Joined: February 2016
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Post by BFTO on May 16, 2018 2:25:06 GMT -5
I have reviewed the video on the gauges now. When the AB lights the P2 drops 0,1-0,2bar.
WITHOUT AB
P2=1,5bar EGT=550 C T2=132 C T1=~20 C
P2=1bar EGT=484 C T2=94 C T1= ~20 C
WITH AB
P2=0,5bar EGT= 567 C T2= 65 C T1= ~20 C
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Post by Johansson on May 16, 2018 16:25:16 GMT -5
Have you measured the fuel pressure for the afterburner? If it is on the low pressure/high flow side the AB will flame out once the pressure inside the duct starts to get near the fuel pressure. With a dump style afterburner I can´t see any reason for adding a flame holder, you should get enough recirculation downstream the flange to keep the flame burning. I´ll find some heat resistant material for you in case you want to try it anyway. Cheers! /Anders
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