Gas turbine assist project

[racket]

Hi Grant

Wheres the 700 deg F ??

Cheers
John

[GrantB]

Isn't 6-800 degrees considered a healthy turbine inlet temperature for a gas turbine engine running a proper air fuel mix and a good combustion?

Thanks

[racket]

Hi Grant

It is possible to have temperatures of 6-800 deg F , but the turbine stage needs to be configured accordingly , your particular application will requires the turbine stage to be sized to accommodate temps of 1400F from the IC engine , trying to reconcile both scenarios is the problem .

It will be necessary to never have a pressure between engine and turbocharger greater than the pressure coming out of the compressor otherwise you will have "backflow" thru the combustor into your intake air , this will probably mean a freefloating turbo without a wastegate that requires your normal 1400 F temps to reach the desired comp discharge pressure(P2 )

By configuring the turbo based DIY engine to run T I T s of 1400 F to produce your desired "operating" boost/P2 with an unrestricted exhaust system , a change over to IC engine exhaust gases at 1400 F won't require any turbine stage adjustment , well not as much , there will be a need to consider any "blow down" energy in the IC engines exhaust , but hopefully it will only be the same total pressure as that coming from the DIY gas turbine combustor which if you were running say 45 psi of boost would be about 43 psi going into the turb scroll, (pressure drop across the intercooler will be roughly the same as across the flametube ) you're going to need a very inefficient turbine stage .................mmmmm, maybe there will be a need for the "wastegate" after all , but not so much for the IC engines exhaust gases but the combustors exhaust so that even with 1400 F for the TIT and 43psi available as the pressure drop across the turbine stage , if the mass flow is reduced by the wastegate then the horsepower produced can be reduced to that which the comp requires...............this is getting complicated :-(

I might have to recheck the BW turbo map and do some calcs for turning it into a DIY engine and see where it ends up .

Have you any ideas as to how the BW turbo will behave as just a turbo on the IC engine ??

Cheers
John

[GrantB]

What do you guys think about this? Its just a quick and dirty model to show the basic layout before i put alot of time into the actual thing.

It has a 5.5in flame tube diameter and its roughly 12in tall. The combustor is a total of 10 in in diameter.

I went to an Arduino meetup at the San Jose Tech Shop last night. There are lots of knowledgeable people there and i even meet a guy who built a diy turbine and was very knowledgeable about turbines so that was really cool, i even showed him this forum so hopefully he will sign up soon. Anyways i realized i needed to get alot of things solidified and ordered so i could get the controller figured out. I really wanted to be able to run jet a or kerosene but the high pressure pumps and injectors to reliably meter and inject the fuel seem like they are overly complex. I thought it would be a little more complex than gasoline efi systems and i was incorrect. Looked into propane and i think it seems promising but im a little worried about its low pressure. Might have to check into pressurizing it with co2. There is also the option of running methanol. Its a little more dangerous than jet A but i think some of the danger is removed compared to a standalone turbine since the running engine will cause some air to be flowing through the combustor while the pumps are on. And since im already familiar with the circuitry to drive a normal fuel/alcohol injector that will simplify things on my end.

-Grant

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[GrantB]

Is this a good start? I was planning on starting the final model so i can start making the combustor.

[racket]

Hi Grant

There needn't be such a large gap between flametube and outer can , if you want to use that sized outer can then I'd be enlarging the flametube to ~7-8"dia , an 8" outer with a 6" flametube might be better , also some sort of cone on the inlet end of the flametube rather than the flat end , this will aid airflow .

Cheers
John

[GrantB]

Does this look a little better? The idea is to have everything modular so i can make a few different versions of things to see what works best IE flame tube.

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[racket]

Yep , thats looking better , the flametube hole pattern needs to be sorted out though .

Cheers
John

[GrantB]

Of course, this is just a simple model.

Thank you for all of your help!