sayem55
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Questions Regarding Engine/APU As A Lab Equipment

Tue Oct 02, 2012 7:18 am

Hello,
I have a few questions regarding engine/APU as a lab equipment. I would greatly appreciate if anyone can help
- Can a small gas turbine engine/APU be bought at around $10,000 ?
- Would it have the sensors/gauges for temperatures, pressures etc ?
- Would it be possible to read the pressure, temperature reading or do I have to buy the avionics as well ?
- Can the engine/APU's speed be reduced (since I need to limit the suction/exhaust of the engine)?
- Do you think it is a good idea to have an engine/APU as a lab equipment ?

Thank you in advance
Regards,
Sayem
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RE: Questions Regarding Engine/APU As A Lab Equipment

Tue Oct 02, 2012 8:51 am

I'll try and answer your questions best I can.

Quoting sayem55 (Thread starter):
Can a small gas turbine engine/APU be bought at around $10,000 ?

No idea, I would assume its possible. I cant help on where to look though, sorry.

Quoting sayem55 (Thread starter):
Would it have the sensors/gauges for temperatures, pressures etc ?

Possibly, depends on the condition and history of the item and how well you can negotiate when it come to sale time.

Quoting sayem55 (Thread starter):
Would it be possible to read the pressure, temperature reading or do I have to buy the avionics as well ?

That depends on a few things, specifically what engine you end up buying and how accurate you want to be with your measurements. Just off the top of my head there is a few sensors that you could read with lab equipment, things like EGT sensors are just thermocouples. Plug those into a suitable multimeter and you can get readings easily. Translating those to an actual, calibrated temperature will be harder, as you would really need the specs for the rest of the indicating system to work out what voltage equates to a given temperature.
Having said that, buying the avionics may not work either, as you'd probably have to set up a whole bunch of different systems, as these things dont always work in isolation.

Quoting sayem55 (Thread starter):
Can the engine/APU's speed be reduced (since I need to limit the suction/exhaust of the engine)?

Within limits, yes. Like any engine, a gas turbine can be throttled within a certain speed range. Operating outside of this range, however, will damage the engine and may lead to a catastrophic failiure. A failure of that kind isn't very likely at the low end of the speed range, but at some point the cycle simply wont be sustainable and it'll shut down.
Bear in mind that jet engines, even small ones, consume a fairly large amount of air and fuel, and create pretty intense exhaust flows and lots of noise while operating.

Quoting sayem55 (Thread starter):
Do you think it is a good idea to have an engine/APU as a lab equipment ?

That really depends on what you are trying to achieve. If you are doing research into the operation of a gas turbine engine for whatever reason, then having your own setup to play around with could be invaluable. I can't think of much other justification to have one setup in a lab, anything a small jet can do with regards to airflow or shaft power output could be done far easier with regular industrial machinery.

Good luck in your project though, keep us posted on the results.
 
sayem55
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RE: Questions Regarding Engine/APU As A Lab Equipment

Tue Oct 02, 2012 9:46 am

Thank you @legs for your input. I sure would keep you posted.

Just to elaborate regarding the sensors required. I need to get Temperature and Pressure readings for
- Compressor exits ( not necessarily all stages)
- Combustion chamber inlet and exit temperatures ( or simply turbine inlet temperature)
- Turbine exits ( not necessarily all stages)
As long as some sensors are there, I can calibrate it to get the decent reading. It does not have to be very precise as it to be used as a lab equipment (not intended for research YET   ).

Regarding speed, I am ASSUMING that even with the lowest throttle reading, the suction and exhaust would be a lot more than a lab room can handle (feel free to correct me). Keeping this in mind, I would like to know if either the RPM or simply the suction of the engine be reduced (i.e. getting rid of the fan, blocking the flow at the inlet etc) ?
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RE: Questions Regarding Engine/APU As A Lab Equipment

Tue Oct 02, 2012 10:11 am

There are model airplane jet engines you can use. These are pretty tiny. But I don't know how small you need the engine.
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RE: Questions Regarding Engine/APU As A Lab Equipment

Tue Oct 02, 2012 10:31 am

Quoting sayem55 (Reply 2):
Regarding speed, I am ASSUMING that even with the lowest throttle reading, the suction and exhaust would be a lot more than a lab room can handle (feel free to correct me). Keeping this in mind, I would like to know if either the RPM or simply the suction of the engine be reduced (i.e. getting rid of the fan, blocking the flow at the inlet etc) ?

Every engine has a minimum idle speed. Once you dip below that speed, the engine can no longer maintain it's operating cycle and will shut down. Removing the fan would essentially unload the engine and it would not function properly. The same can be said if you restrict airflow into the engine. Not to mention that if you hinder air flowing through the engine, you could cause significant heat/fire damage in the combustion section.

I've seen several engines used in a lab environment (both turbine and piston engines) for taking measurements, but all of them needed to be operated either outdoors or in a ducted test cell. As for taking measurements, it depends on how the engine is equipped. If it doesn't measure the parameters you are looking for, you may be able to have custom instrumentation made, such as to take measurements from the borescope ports, but that could potentially get pricey.
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RE: Questions Regarding Engine/APU As A Lab Equipment

Tue Oct 02, 2012 12:15 pm

A colleague bought a jet engine (Czech made, from a L-29 jet trainer) without paperwork, but in running condition, for less than €2000 on eBay. As a jet engine mechanic, he wants to build himself a test stand in his garden and run it for fun.

Quoting sayem55 (Reply 2):
Just to elaborate regarding the sensors required. I need to get Temperature and Pressure readings for
- Compressor exits ( not necessarily all stages)
- Combustion chamber inlet and exit temperatures ( or simply turbine inlet temperature)
- Turbine exits ( not necessarily all stages)
As long as some sensors are there, I can calibrate it to get the decent reading. It does not have to be very precise as it to be used as a lab equipment (not intended for research YET ).

Unless the engine has a T3 probe already installed, you might have to modify the diffusor casing. Since the engine will not have to fly again, it could be done by any competent machinist (drill a hole of the right diameter and tap it. You can also install a PT3 probe as well for the pressures). This would give you compressor outlet / combustor inlet temperatures and pressures.

Turbine inlet temperature would be similar, drill a few holes around the diameter, maybe spaced 120 degrees apart and tap them. If the material on the casing is too thin, you might have to have a bushing welded to it on the outside, but for this you need to know the alloy of the casing.

Or you´ll use the existing boroscope ports.

All engines have a turbine exit temperature indication (which is vrequired to monitor engine starting and operation).

You´ll need a test cell though and a massive stand to mount the engine on (which can take the thrust loads).

Test cells usually also have an armoured control room, not just as noise protection, but also in case of catastrophic failure of the engine.

Jan

Jan
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RE: Questions Regarding Engine/APU As A Lab Equipment

Tue Oct 02, 2012 12:35 pm

Perhaps you can pick up some useful tips here:
http://jetpropulsion.co.uk/
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tdscanuck
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RE: Questions Regarding Engine/APU As A Lab Equipment

Tue Oct 02, 2012 6:18 pm

Quoting sayem55 (Thread starter):
- Can a small gas turbine engine/APU be bought at around $10,000 ?

Yes. Very small. For a bit more money, you can get one of these:
http://www.turbinetechnologies.com/E...LabProducts/TurbojetEngineLab.aspx

My undergrad lab had one, they're tremendous fun.

Quoting sayem55 (Thread starter):
- Would it have the sensors/gauges for temperatures, pressures etc ?

Depends on the exact model. You can fit whatever's missing if you're handy.

Quoting sayem55 (Thread starter):
- Would it be possible to read the pressure, temperature reading or do I have to buy the avionics as well ?

You can generally read directly...for durability reasons, engines rarely use digital sensors deep in the engine.

Quoting sayem55 (Thread starter):
- Can the engine/APU's speed be reduced (since I need to limit the suction/exhaust of the engine)?

Not below idle.

Quoting sayem55 (Thread starter):
- Do you think it is a good idea to have an engine/APU as a lab equipment ?

It depends on what you want to measure. It's really fun though.

Quoting sayem55 (Reply 2):
Regarding speed, I am ASSUMING that even with the lowest throttle reading, the suction and exhaust would be a lot more than a lab room can handle (feel free to correct me)

You absolutely need an independant outside air supply and exhaust. Even a very small engine will rapidly fill any real-sized lab with fumes, which is bad for both you and the engine.

Tom.
 
sayem55
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RE: Questions Regarding Engine/APU As A Lab Equipment

Wed Oct 03, 2012 7:36 am

Thank you all for your inputs.
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RE: Questions Regarding Engine/APU As A Lab Equipment

Wed Oct 03, 2012 8:31 am

Here's a small RR RB 211 that someone starts and runs in their backyard. Found it at the airport.. http://www.youtube.com/watch?v=qM7ksfRVF70
 
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RE: Questions Regarding Engine/APU As A Lab Equipment

Wed Oct 03, 2012 9:14 pm

Quoting sayem55 (Reply 2):
Regarding speed, I am ASSUMING that even with the lowest throttle reading, the suction and exhaust would be a lot more than a lab room can handle (feel free to correct me). Keeping this in mind, I would like to know if either the RPM or simply the suction of the engine be reduced (i.e. getting rid of the fan, blocking the flow at the inlet etc) ?

When I was a student at University we had an old APU (a Rolls Royce Palouste) which was used for lab experiments. Intake and exhaust were not open in the lab, there was inlet and exhaust ducting to the outside for safety and noise reasons. So running at full speed should not be a problem.

A small APU is practical as a means of running lab experiments on a gas turbine engine. Another possiblility is a turboshaft engine, which might be a better lab tool as it is designed to run at various speeds and loads. An aircraft engine produces substantial thrust and the installation problems are likely to be many times greater, something approaching a full scale test cell. It ought to be possible to obtain an APU or turboshaft from an aircraft spares supplier reasonably cheaply if it's not certified for flight.

Regarding instrumentation, the engine will have its own transducers and as long as you can identify the types of signal outputs it provides you should be able to connect it to a data recording system easily enough. Adding additional transducers for lab purposes might be problematic.

[Edited 2012-10-03 14:24:45]
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sayem55
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RE: Questions Regarding Engine/APU As A Lab Equipment

Thu Oct 04, 2012 5:53 am

@Jetlegged

Thank you for you help. You mentioned turboshaft; Would a turbo prop work ? I found a few used PT6s that are available.

@T prop
Thank you too
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RE: Questions Regarding Engine/APU As A Lab Equipment

Thu Oct 04, 2012 1:44 pm

Quoting sayem55 (Reply 11):
Thank you for you help. You mentioned turboshaft; Would a turbo prop work ? I found a few used PT6s that are available.

I suppose so, as long as you have the equipment to absorb the shaft power output it produces. You'd need to do that anyway to measure power output in the lab. However, the bigger and more powerful the engine the more expensive it will be to install and operate.
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RE: Questions Regarding Engine/APU As A Lab Equipment

Thu Oct 04, 2012 11:36 pm

Quoting tdscanuck (Reply 7):

Other possible suppliers of turnkey gas turbine lab rigs would be one of the following;

www.tecquipment.com/
www.tecquipment.com/Thermodynamics/Gas-Turbines.aspx?page=1

www.edibon.com/
www.edibon.com/products/?area=thermo...icsthermotechnics&subarea=turbines

However, I suspect that any of these rigs would be somewhat in excess of your $10,000 budget. Have you thought of making your own rig from an automotive turbocharger? A good source of info would be the following;

www.rcdon.com/index.html
www.rcdon.com/html/experimental_projects.html

This is what my uni uses for teaching purposes. I suspect you could readily get a decent test rig happening within your budget with this option.

Regards, JetMech

[Edited 2012-10-04 16:55:48]
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MD11Engineer
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RE: Questions Regarding Engine/APU As A Lab Equipment

Mon Oct 08, 2012 8:33 am

You can get used engines quite cheaply. E.g. we have a few Marboré II engines sitting in our hangar, to be used (after overhaul) as spares for a Fouga Magister.

Get one of these early turbojet engines (if they come without certification paperwork like an EASA Form 1 or a FAA 8130-3 they are usually much cheaper, but you can´t install them legally on aircraft). They are simple and tough and can withstand some abuse (within limits).
Get a local welder to build a frame, which can carry the loads (and maybe contains a load cell for measuring thrust) and set it up in a building with an air intake, an exhaust tunnel and a soundproof control stand. For a Marboré II the thrust is about 4500 N, so it is manageable.

Jan

[Edited 2012-10-08 01:33:51]
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sayem55
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RE: Questions Regarding Engine/APU As A Lab Equipment

Mon Oct 08, 2012 12:45 pm

Thank you.

@JetMech
As you guessed, they are way over $10,000 (close to $40k).
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RE: Questions Regarding Engine/APU As A Lab Equipment

Tue Oct 09, 2012 12:24 am

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