Yep, she's running a bit hot at the outlet end of the flametube , ideally the flametube wall should be hottest in the primary zone where the fuel is injected , it should then start to run cooler from the secondary holes and show no signs of overheating once past the main dilution holes in the tertiary zone , ......................a change of propane injector to one with radial holes will/should fix the problem :-)
Propane is a fast burning fuel that copes with wide F/A ratios so an ideal fuel to use.
Subject: [DIYGasTurbines] Re: Boost pressures and EGTs
I just took the flame tube out and inpected it. It seams as if the flame is traveling to far twards the turbine side. I think I will make another injector like you said that sprays around insted of striaght in. I dont want to make too many changes at once. I will just try one thing at a time!
--- In DIYGasTurbines@yahoogroups.com, "John WALLIS \(Racketmotorman\)" <racketmotorman@...> wrote: > > Hi Ken > > 2.5"inducer gives us 4.9 sq inches , we need ~3 times inducer area for our flametube crossection , so ~14.7 sq ins , or ~4.3 inch ID as a minimum diameter , preferably 5 inches to make it simpler to get good combustion first time . > > With a 2.5 inch inducer you probably have an exducer of say ~3.3 inches , so your 99, 999 rpm tach should be just enough ...................but please check the comp dia and do the calcs so that you don't exceed that 1450 ft/sec limit :-) > > Cheers > John > > ----- Original Message ----- > From: sswhuevos@... > To: DIYGasTurbines@yahoogroups.com > Sent: Friday, January 27, 2012 7:55 AM > Subject: Re: [DIYGasTurbines] Re: Boost pressures and EGTs > > > > I'm going to do some work on it tonight. I haven't taken the flame tube out yet to inspect how it is burning. Thanks for the info on the injector. > > The inlet on the turbo is 2.5 inches. I used that measurement to calculate flame tube specs roughly. > > Ken > > Sent on the Sprint® Now Network from my BlackBerry® > > ---------------------------------------------------------- > > From: "John WALLIS \(Racketmotorman\)" <racketmotorman@...> > Sender: DIYGasTurbines@yahoogroups.com > Date: Fri, 27 Jan 2012 07:51:21 +1000 > To: <DIYGasTurbines@yahoogroups.com> > ReplyTo: DIYGasTurbines@yahoogroups.com > Subject: Re: [DIYGasTurbines] Re: Boost pressures and EGTs > > > > > Hi Ken > > The rpm limit will depend on the wheel diameter as the Group has an upper tip speed limit of 1450 ft/sec for safety reasons , so measure your compressor wheel diameter , put the number into Jetspecs Turbo Analysis and it will give you a rpm limit for your engine . > > Cheers > John > > > ----- Original Message ----- > From: sswhuevos@... > To: DIYGasTurbines@yahoogroups.com > Sent: Thursday, January 26, 2012 11:46 PM > Subject: Re: [DIYGasTurbines] Re: Boost pressures and EGTs > > > > I ordered a tach that goes to 99,999 rpm. It should be here today. What kind of RPM should I be looking for? > > Ken > > Sent on the Sprint® Now Network from my BlackBerry® > > ---------------------------------------------------------- > > From: "mot_mole" <jnissen@...> > Sender: DIYGasTurbines@yahoogroups.com > Date: Thu, 26 Jan 2012 07:07:54 -0000 > To: <DIYGasTurbines@yahoogroups.com> > ReplyTo: DIYGasTurbines@yahoogroups.com > Subject: [DIYGasTurbines] Re: Boost pressures and EGTs > > > > Ken fairly low T4 temps. DO you have a jet nozzle on it or just a straight pipe? At 22 to 24 PSI that is really pushing it. Be careful of over revving. Do you have a tach for it? > > Sounds like it's really moving. > > --- In DIYGasTurbines@yahoogroups.com, "Ken Herbert" <sswhuevos@> wrote: > > > > I put a boost gauge on my gas turbine last weekend and I saw about 22-24 PSI at full throttle running on propane. My EGT at turbine and thrust tube was about 750-800F. The compressor side was around 1600F. Is this a good place I need to be? > > > > http://www.youtube.com/user/hyprmtr?blend=1&ob=video-mustangbase > > > > > > Ken > > >
I put a boost gauge on my gas turbine last weekend and I saw about 22-24 PSI at full throttle running on propane. My EGT at turbine and thrust tube was about...
Ken fairly low T4 temps. DO you have a jet nozzle on it or just a straight pipe? At 22 to 24 PSI that is really pushing it. Be careful of over revving. Do you...
I ordered a tach that goes to 99,999 rpm. It should be here today. What kind of RPM should I be looking for? Ken Sent on the Sprint® Now Network from my...
Hi Ken I just had a look at the video and I'm a bit concerned about the turbine wheel temperature as it appears there is flames at the turbine , without any...
The injector is just a 1/4 inch copper tube I put in a drill chuck and crimped down to almost nothing. The flame tube was built with a 4 inch exhaust tubing...
Hi Ken Injectors need to have "radial" holes (relative to the flametube axis) otherwise the propane will be injected too far down the flametube before ignition...
Hi Ken The rpm limit will depend on the wheel diameter as the Group has an upper tip speed limit of 1450 ft/sec for safety reasons , so measure your...
I'm going to do some work on it tonight. I haven't taken the flame tube out yet to inspect how it is burning. Thanks for the info on the injector. The inlet...
Hi Ken 2.5"inducer gives us 4.9 sq inches , we need ~3 times inducer area for our flametube crossection , so ~14.7 sq ins , or ~4.3 inch ID as a minimum...
I just took the flame tube out and inpected it. It seams as if the flame is traveling to far twards the turbine side. I think I will make another injector like...
Hi Ken Yep, she's running a bit hot at the outlet end of the flametube , ideally the flametube wall should be hottest in the primary zone where the fuel is...
I'm working on the new injector right now! I will run it tonight and see how it goes. I will try out my new tach also. Thank you so much for your help! Ken...
Hi Ken All the best with the next test , only too happy to help out :-) Cheers John ... From: Ken Herbert To: DIYGasTurbines@yahoogroups.com Sent: Saturday,...
I did a lot of different testing this weekend and did not really change much in performance. I tried a radial injector and it did light and run but it would...
Hi Ken How many radial holes, and what size , in the injector that didn't work ?? .....................radial holes should cure problems not create them ,...
I am using a 1/4 inch copper tube that I mashed almost completely closed for the injector that works well. I made another injector the same way but I close it...
Hi Ken 3 radial holes in the fuel injector aren't enough as there are large "wedges" of the flametube crossection without any fuel , we need at least 6 holes...
My SJ10 with an 1.70" compressor inducer idles at ~50,000 RPM with a P2 = 4 to 5 psig. For the injector, I used a brass threaded with 6 equally spaced 0.040"...
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