Gluhareff 130R power failure issue still open ... Any Idear?

[luc]

Raymond,

What I need, is a nozzle that will have the same performances @ 225 psi. as the Gluhareff nozzle when it is at 700 psi.

A basic sketch with Acad 14 will do.

Thanks,

Luc

[Raymond G]

Luc Wrote

What I need, is a nozzle that will have the same performances @ 225 psi. as the Gluhareff nozzle when it is at 700 psi.

A basic sketch with Acad 14 will do.

If I understand correctly, you want a nozzle that will give the same plume at 225 psi that the standard nozzle gives at 700 psi? As we discussed, increased pressure will not increase jet velocity, it will only increase mass flow. Since 700 psi is 3.11 times 225 psi, you will need a nozzle with 3.11 times the area to produce the same mass flow; this would correspond to a throat diameter increase from .250 in to .440 inches. However, you cannot exactly duplicate the 700 psi case, as there is additional pressure expansion in the stage 1 ejector tube (in the 700 psi flow case) which may or may not enhance performance. If you want to spend some CFD time, I would work on modeling how well the propane jet interacts with the 1 stage ejector air.

Raymond

p.s. Since this case is so simple, i.e. simply scaling up the existin nozzle interals to .440 in dia throat, I have not included a sketch. It is worth noting that the rest of the system my not be able to handle the 3.11 increase in mass flow when the resevoir pressure remains at 225 psi.

[Viv]

Its bit of a snake swallowing its own tail and forming a hoop when you think of it.

improving the nozzle will alter the air fuel mixture so we need to watch the size of the first stack.

Viv

[Raymond G]

IIR, Viv had asked for a drawing of the existing nozzle, so I drew one up real fast for him. Also gives me a chance to try uploading to this group

Regards,
Raymond

[Viv]

IIR, Viv had asked for a drawing of the existing nozzle, so I drew one up real fast for him. Also gives me a chance to try uploading to this group

Regards,
Raymond

Nice drawing Raymond but I must admit if this is the nozzle that these engines use I am surprised they do as well as they have!

But I will temper that statement against the intended application for them and that they did well enough at it.

But lets face it with Lucs CFD we can rematch the intake stake to a new high velocity nozzle and raise the performance, what do you think?

Viv

[Raymond G]

Viv Wrote:

But lets face it with Lucs CFD we can rematch the intake stake to a new high velocity nozzle and raise the performance, what do you think?

I agree that the CFD offers a great opportunity to improve the design. Sure wish I had access....
Anyway, what I see as the real potential here is to model the actual ejectors to improve performance. I seem to remember once seeing a NACA/NASA document where a CFD study of ejectors was able to show optimal length for sonic tuning. I have been been looking through all of my old tech papers, but haven't found it yet. Eventually Luc may be able to model the entire induction system with the jet nozzle and all three ejector stages. Then you would really be able to see what's going on.

As a side note, in the Riley Gluey manuals, there is an analysis of the induction system for the G8-2-15 based upon some "experimental" numbers in which EACH stage achieves roughly 67% effiency at converting the fuel jet's kinetic energy to induced air kinetic energy. That's not very good and should leave lots of room for improvement. as an example, with three stages, the system's efficiency becomes .67*.67*.67=.30 or 30% !!! If induction efficiencies are improved only slightly, say to 75%, then system efficiency increases to 42% still not huge, but it is a 40% improvement. Of course this may be the root of Luc's problems. If instead of 67% per stage, he is getting say 65% (only a 2% reduction) then system efficiency is reduced by 10% to 27%! And because the system's performance is very nonlinear based upon induction pressure (which is proportional to induction kinetic energy) you could loose more than 10% thrust from lost induced mass flow and an additional 10% thrust from lost pressure ratio. So it is entirely possible that a mere 2% per stage efficiency loss could result in a huge engine performance loss.

The process above is known as a sensitivity anaylsis and shows just how sensitive this design is to induction system variance. There could be any number of little tweeks that Gluhareff consistantly did that could acount for this level of variation (2% per stage) that were too subtle to ever show up on the 'engineering' drawings. Maybe the surface finish of the ejector tubes is suppossed to be highly polished, or maybe it needs to be rough.

The Gluhareff plans that I have do not call out tolerances or surface finishes, so right there I see a probable source of 2% variance per stage. Sorry this post has rambled on so, but I have been thinking 'out loud' on a possible culprit for G8-2-130 power loss.

Regards,
Raymond

[Viv]

Shit i have this sudden picture of lots of little servo motors driven by an fft program running on a PIC motoring the stack elements backwards and forwards autotuning the engine for max thrust:-)

It may have to happen just to allow for the awfull winters they have up in Canada:-)

Viv

[Dave]

OK guys. I have never posted to the forum before so I will start with the smallest file first. Viv, if all goes well you should get a slightly crooked copy of the nozzle from my set of plans. If I scanned the forum correctly Luc should be able to supply you with much better info from his CD. I will try posting the Iowa State report next.
Dave

[Dave]

HELP. I'VE FALLEN AND I CAN'T GET UPLOAD!

Yes the small file with the nozzle went up easily enough, but every attempt to upload the entire report gives me the following error:
" Upload Error: Could not upload Attachment to ./files/part1.pdf."

According to the info page on allowable file types and sizes there should not be an issue as the max file size is listed as 10MEG. The first report file is just a bit over 2MEG and the second a little over 1MEG.

Any ideas on what I might be missing, or is the server simply full?

Dave

[Viv]

HELP. I'VE FALLEN AND I CAN'T GET UPLOAD!

Yes the small file with the nozzle went up easily enough, but every attempt to upload the entire report gives me the following error:
" Upload Error: Could not upload Attachment to ./files/part1.pdf."

According to the info page on allowable file types and sizes there should not be an issue as the max file size is listed as 10MEG. The first report file is just a bit over 2MEG and the second a little over 1MEG.

Any ideas on what I might be missing, or is the server simply full?

Dave

Dave thats brilliant, just email me a copy so I can get started reading, Luc and Raymond will probably want it emailed too but check they have the bandwidth first.

If my vivcollins@mac.com address refuses the big one send it to my viv@wellystreet.co.uk address, but let me know:-)

Viv

[Dave]

Viv, files were sent to both email addresses. When sent together to the first address they kicked back. Resent in two parts to first address, then together to your second address.

If anyone else wants the reports emailed directly, just let me know. It will be late tonight or early tomorrow, but I will give it a go.

I will also try to post the files to the forum again at a later date.

Dave

[Viv]

Viv, files were sent to both email addresses. When sent together to the first address they kicked back. Resent in two parts to first address, then together to your second address.

If anyone else wants the reports emailed directly, just let me know. It will be late tonight or early tomorrow, but I will give it a go.

I will also try to post the files to the forum again at a later date.

Dave

Ok Dave I have sent a copy to Luc but I have also sent a copy to Kenneth and asked him to post it as I cant post it to the forum ether.

I don't have have your address Raymond so if you email me I will send it to you.

Any body else wants a copy in the mean time just mail me.

Viv

[Viv]

I have put the IOW state reports on my ftp space at .mac

link here

Viv
PS If it works:-)

[Viv]

Well to move on, I read the report but I was not that impressed by their methodology or the way they put a rider on every statement saying it may or may not be true as they could not claim any accuracy for any of their readings.

But I did have a good laugh about the strain gauges mounted above the red hot engine on the test cell, wont make that mistake again then boys:-)

It really only confirms in a way the basic processes we have already identified, we may as well move on with our own plans as the reported thrust figures I think still can not be trusted.

Viv

[luc]

Hi guys ... I am back ... He he he,

Okeyy....First,
Yes Ramond ... I am a Pro ... he he he ... At modeling and analysis, and this is only because I am so poor at Math. That why I relly so much on software. So, if you guys can calculate a nozzle or an intake stack, I can model it and simulate it in CFD ... With no problem at all. Just ask for it and you will have it.

Viv,... I totally agree with you that the Iowa repport is a bit of disapointment (Still ... Good work Dave). They always kind of cover their *** with "probably" or "May" and "May not". I can't even consider their 110 pounds thrust recording to be a real proof. I also was very puzzled with their problems in running their engine above 150 psi. pressure, when I run mine at 225 psi. with no problem.

Also, as stated in their abstract, one of the engine was purchased from "Vortech", were I purchased my first one. Let me tell you something about the guy who build the engines for "Vorthec". Is name is Tim Piazza and all the guy can do ... His WELD ... That all. Actually, I am convinced that he could build 5 engines in a row and all 5 engines could go from 20 to 200 pounds of thrust, without him noticing any difference.

Hoooo ... Buy the way, "Vorthec" advertise their totally built engine for $3,200.00 US. I have built two 130R engine for less then $1,500.00 CND.
So guys... Don't go waisting your money ... Tell me and I can talk to my boss and see what we can do for you. We also have a "Coils" jig and can make them in no time.

So...Get your calculator and pencil ...guys, I am ready for 130R improvement.

Regards,

Luc