Anyone used GE locomotive turbo impellor/turbine?

[finiteparts]

Titanium is a low temperature material that is unusable for machining turbine disks, much less the blades.  If you go to page 36 of the below pdf, you will see a plot of yield strength of various metals verses temperature.  It clearly illustrates the inability of titanium alloys to maintain strength at turbine related temepratures.

www.nasa.gov/pdf/601242main_X15ExtendingFrontiersFlight-ebook.pdf

Now, I will admit that TiAl alloys are ok for the lower temperature range of modern turbine engines(and turbochargers) and are used in the LPT stages of large commercial turbofans, but they are a completely different alloy process called intermetallics and are very difficult materials to work with.   Casting them is not easy and the post processing steps are key to keeping the part from just popping apart due to residual internal strain.

As John said, you would want to use a high nickel superalloy, such as Inconel 718 or Mar-M-247 if machined or 713LC if cast.  That cost of any of these at that size is going to be substantial and then the cost of machining superalloys is also high due to the fact that not every maching shop can do it well.

As I said before, you are better off finding a used aircraft turbine and repurposing it.  It has already been designed and made to live in the environment that you are wanting.  Or, find a good used larger turbocharger and run it at the reduced turbine inlet temperature....it will still be more fun than any other generator that you could buy.  You only need the super high temperature if you are trying to squeeze every bit of thrust or power out of the engine.   If you want something that runs and makes you the coolest person in the neighborhood, that is still achievable with the modified turbo.

Good luck,

Chris

[miuge]

What about the mighty Holset HT100 turbo? I believe these are still in production, used in big Cummins engines. Standard turbocharger layout, nothing fancy or too exotic and easily available.

[racket]

Your desired power output is very important , the loco sized wheels might be able to supply a modest output but at very poor fuel burn rate , whereas a HX82 turbo could supply the same power output at much improved fuel burn rate due to the lower air mass flow rate , the relatively "small" TV84 based turbo engine in my bike jetandturbineowners.proboards.com/thread/1366/tv84-turbine-bike produced 115 HP on the dyno .

If you only need <100HP , used a readily available turbo , if a lot more HP take Chris' advice above and look at used commercial turbine engines , it'll save you a lot of headaches .

Cheers
John

[wyldon]

Sept 18, 2022 17:04:59 GMT -5 racket said:

Your desired power output is very important , the loco sized wheels might be able to supply a modest output but at very poor fuel burn rate , whereas a HX82 turbo could supply the same power output at much improved fuel burn rate due to the lower air mass flow rate , the relatively "small" TV84 based turbo engine in my bike jetandturbineowners.proboards.com/thread/1366/tv84-turbine-bike produced 115 HP on the dyno .

If you only need <100HP , used a readily available turbo , if a lot more HP take Chris' advice above and look at used commercial turbine engines , it'll save you a lot of headaches .

Cheers
John

Thats good information, thank you! Power goal should be about 200shp. I think from now on I'll disregard the generator part.

[wyldon]

Sept 18, 2022 13:57:30 GMT -5 miuge said:

What about the mighty Holset HT100 turbo? I believe these are still in production, used in big Cummins engines. Standard turbocharger layout, nothing fancy or too exotic and easily available.

Those are huge, I like em. Insanely cheap for the size as well.

[wyldon]

Sept 18, 2022 11:50:30 GMT -5 finiteparts said:

Titanium is a low temperature material that is unusable for machining turbine disks, much less the blades.  If you go to page 36 of the below pdf, you will see a plot of yield strength of various metals verses temperature.  It clearly illustrates the inability of titanium alloys to maintain strength at turbine related temepratures.

www.nasa.gov/pdf/601242main_X15ExtendingFrontiersFlight-ebook.pdf

Now, I will admit that TiAl alloys are ok for the lower temperature range of modern turbine engines(and turbochargers) and are used in the LPT stages of large commercial turbofans, but they are a completely different alloy process called intermetallics and are very difficult materials to work with.   Casting them is not easy and the post processing steps are key to keeping the part from just popping apart due to residual internal strain.

As John said, you would want to use a high nickel superalloy, such as Inconel 718 or Mar-M-247 if machined or 713LC if cast.  That cost of any of these at that size is going to be substantial and then the cost of machining superalloys is also high due to the fact that not every maching shop can do it well.

As I said before, you are better off finding a used aircraft turbine and repurposing it.  It has already been designed and made to live in the environment that you are wanting.  Or, find a good used larger turbocharger and run it at the reduced turbine inlet temperature....it will still be more fun than any other generator that you could buy.  You only need the super high temperature if you are trying to squeeze every bit of thrust or power out of the engine.   If you want something that runs and makes you the coolest person in the neighborhood, that is still achievable with the modified turbo.

Good luck,

Chris

Thank you chris!

[wyldon]

Sept 18, 2022 17:04:59 GMT -5 racket said:

Your desired power output is very important , the loco sized wheels might be able to supply a modest output but at very poor fuel burn rate , whereas a HX82 turbo could supply the same power output at much improved fuel burn rate due to the lower air mass flow rate , the relatively "small" TV84 based turbo engine in my bike jetandturbineowners.proboards.com/thread/1366/tv84-turbine-bike produced 115 HP on the dyno .

If you only need <100HP , used a readily available turbo , if a lot more HP take Chris' advice above and look at used commercial turbine engines , it'll save you a lot of headaches .

Cheers
John

This is a question on the side, is the result that jetspecs produce absolute? Is it possible to change these dimensions (for example, increase x and decrease y at 1:1)? The current design that I am suggested would look like a hotdog lol. Any ideas?

[racket]

There is scope for some dimensional changes , but you'll need more sophisticated fuel and air presentation the smaller you go .

3 times comp inducer area as a minimum for the flametube cross sectional area is non negotable , length can be shortened depending on how well fuel and air are mixed and speed of combustion