Post by ozzyslastneuron on Feb 9, 2017 10:20:29 GMT -5
Hello everybody,
First, please excuse my partially terrible English and my ridiculously long phrasing, not a native speaker here.
I looked around some and found this place quite knowledgeable and after seeing how you guys patiently handled that rather annoyingly stubborn Syler guy, Anders effort in documenting his stunning Bike built and racket, finitelements and many others taking the time to give really comprehensive answers even though it's sometimes improbable that the person even understands a word they are talking about, i thought this was the Board to ask for help evaluating this kind of project.
I got some more or less fundamental Questions.
First of all, i read that Racket gave some Tips for basic literature concerning this topic, so I'd like to ask what Books/Papers/whatever you all could suggest.
Specifically for a unit with neither weight nor Size limitations, more on the reliability side than max power/power weight ratio.
I think most books about RC engines are inherently concerned about weight/power ratios, for obvious reasons...
The second question(s) is if someone here has ever ran a turbocharger based turbine, or even better a turboshaft, for an extended time?
Like 3/6/12 hours?
I doubt it cause its of no use for most applications here, but perhaps as hardcore stress test or the like.
What are the main factors here, would i be fine as long as i keep the TIT/TOT/PR in check, of course with a reliable and proper sized lubrication/cooling system?
Could i expect a lifetime/Mtbf as the turbocharger has in a (petrol) IC car engine, or even more since it could run in more defined and constant operating conditions, no change in rpm, no thermal cycling etc., and has no weight restriction?
So, that for a starter, to evaluate if it even makes sense to go deeper or if i can scrap the idea all together.
The goal would be to construct and fiddle around till i got a running selfmade kind of nano-APU, about 0.5-1.5KWel.
[The next goal would be WHR with a adsorption chiller or a ORC/classic rankine cycle. A friend constructet one for the condensation stage of his Boiler, gaining ~500Wel, but he is very reluctant to give any specific details because he has the illusion he could get a patent for something in it, as if this wouldn't be allready extensively covered in any possible direction...]
There is at least one unit soon (or even already) to be commercially available, based on of-the-shelf turbocharger parts that's putting out 1-3KWel and should have maintenance intervals about 5000 hours and around 40000h till replacement of the Turb/Gen/Comp unit i think.
A replacement Compressor/generator/turbine block, as i was unofficially told, should be available for only ~700-800€.
It's a single shaft design with the generator rotor on the turbocharger shaft, between compressor and turbine.
Called Enertwin from MTT, and an even more efficient design from Capstone, but way to big, >3KWel, and expensive.
But, yeah, using that as the base would at best be half as fun, wouldn't it?
Are there any known and tried turbocharger/turbocharger-turbine combinations for use in that power range?
If it is possible to reach a comparable performance with a self designed free turbine unit i could possibly partially compensate my lack of skill with the brute force method (read: Money) since these turbine micro-/nano-chp's cost a lot of cake too. Plus i could finally justify to get a real mill, lathe, cutter, tig and all the other great toys for us partially grownups
I don't expect to get something like that done fast, i know it takes a lot of time, even more compassion, skill and sometimes a high frustration tolerance.
I would project it for the next two to five years if i decide to. The second goal again in the two to five year range.
Btw I'm unemployed and don't have a family yet, so nothing annoying like the need to work for a lousy salary interferes with these really important things in life
One last thing, has anyone here ever tried to print parts with a 3D printer to make a mold and get them casted?
Parts like the diffuser or the turbine guide vanes with complex geometry could possibly be manufactured quite cheap and in good Quality that way.
It would even be possible to 3D-scan commercial turbine parts, resize, modify and then get them casted, lowering the price even more as the number of copys goes up.
Here in Germany it's relatively cheap to get something casted compared to cnc or manual milling like Anders did with the diffuser, with good quality of detail as long as the material hasn't to be very sophisticated. I know a guy who casts jewellery with very fine details and they are nearly done just out the mold.
I don't know exactly how it is with materials that are more heat resistant, but turbocharger turbine volutes are normally casted steel, right?
For a hobbyists it could be quite difficult to cast steel but not for a proffesional company!
Any thoughts on that?
Great Board with great guys here it seems. So, please excuse my general cluelessness, just looking for a point to start from if it's possible after all.
MfG,
Ozzy
First, please excuse my partially terrible English and my ridiculously long phrasing, not a native speaker here.
I looked around some and found this place quite knowledgeable and after seeing how you guys patiently handled that rather annoyingly stubborn Syler guy, Anders effort in documenting his stunning Bike built and racket, finitelements and many others taking the time to give really comprehensive answers even though it's sometimes improbable that the person even understands a word they are talking about, i thought this was the Board to ask for help evaluating this kind of project.
I got some more or less fundamental Questions.
First of all, i read that Racket gave some Tips for basic literature concerning this topic, so I'd like to ask what Books/Papers/whatever you all could suggest.
Specifically for a unit with neither weight nor Size limitations, more on the reliability side than max power/power weight ratio.
I think most books about RC engines are inherently concerned about weight/power ratios, for obvious reasons...
The second question(s) is if someone here has ever ran a turbocharger based turbine, or even better a turboshaft, for an extended time?
Like 3/6/12 hours?
I doubt it cause its of no use for most applications here, but perhaps as hardcore stress test or the like.
What are the main factors here, would i be fine as long as i keep the TIT/TOT/PR in check, of course with a reliable and proper sized lubrication/cooling system?
Could i expect a lifetime/Mtbf as the turbocharger has in a (petrol) IC car engine, or even more since it could run in more defined and constant operating conditions, no change in rpm, no thermal cycling etc., and has no weight restriction?
So, that for a starter, to evaluate if it even makes sense to go deeper or if i can scrap the idea all together.
The goal would be to construct and fiddle around till i got a running selfmade kind of nano-APU, about 0.5-1.5KWel.
[The next goal would be WHR with a adsorption chiller or a ORC/classic rankine cycle. A friend constructet one for the condensation stage of his Boiler, gaining ~500Wel, but he is very reluctant to give any specific details because he has the illusion he could get a patent for something in it, as if this wouldn't be allready extensively covered in any possible direction...]
There is at least one unit soon (or even already) to be commercially available, based on of-the-shelf turbocharger parts that's putting out 1-3KWel and should have maintenance intervals about 5000 hours and around 40000h till replacement of the Turb/Gen/Comp unit i think.
A replacement Compressor/generator/turbine block, as i was unofficially told, should be available for only ~700-800€.
It's a single shaft design with the generator rotor on the turbocharger shaft, between compressor and turbine.
Called Enertwin from MTT, and an even more efficient design from Capstone, but way to big, >3KWel, and expensive.
But, yeah, using that as the base would at best be half as fun, wouldn't it?
Are there any known and tried turbocharger/turbocharger-turbine combinations for use in that power range?
If it is possible to reach a comparable performance with a self designed free turbine unit i could possibly partially compensate my lack of skill with the brute force method (read: Money) since these turbine micro-/nano-chp's cost a lot of cake too. Plus i could finally justify to get a real mill, lathe, cutter, tig and all the other great toys for us partially grownups
I don't expect to get something like that done fast, i know it takes a lot of time, even more compassion, skill and sometimes a high frustration tolerance.
I would project it for the next two to five years if i decide to. The second goal again in the two to five year range.
Btw I'm unemployed and don't have a family yet, so nothing annoying like the need to work for a lousy salary interferes with these really important things in life
One last thing, has anyone here ever tried to print parts with a 3D printer to make a mold and get them casted?
Parts like the diffuser or the turbine guide vanes with complex geometry could possibly be manufactured quite cheap and in good Quality that way.
It would even be possible to 3D-scan commercial turbine parts, resize, modify and then get them casted, lowering the price even more as the number of copys goes up.
Here in Germany it's relatively cheap to get something casted compared to cnc or manual milling like Anders did with the diffuser, with good quality of detail as long as the material hasn't to be very sophisticated. I know a guy who casts jewellery with very fine details and they are nearly done just out the mold.
I don't know exactly how it is with materials that are more heat resistant, but turbocharger turbine volutes are normally casted steel, right?
For a hobbyists it could be quite difficult to cast steel but not for a proffesional company!
Any thoughts on that?
Great Board with great guys here it seems. So, please excuse my general cluelessness, just looking for a point to start from if it's possible after all.
MfG,
Ozzy