Turbine powered without exhaust

[AnArKey]

This is a little idea I have been bouncing around my skull the last few days. Goes something like this.

Turbo is no longer part of the exhaust. Exhaust would be like a NA.

Turbo is powered only when needed. Sits idle most of the time.

Power to spin the turbine will be provided by the following:

Sealed combustion chamber at the inlet to the turbine.
Inject propane, pure O2 gas, and water into chamber, and ignite.

The ratio of propane/O2 will be about 1:3.62 (weight), which is a stoich mixture. There will be a lot more water, enough to end up with a final water steam temp somewhere in the 500-800F range. That's about 13x as much water as propane to get that.

Consideration 1: Will the mixture burn? Pure O2 makes it VERY flammable, however all the water does the opposite.

I'm also figuring that any turbo to be used this way can have a VERY small turbine wheel and AR. I'm hoping this will reduce the total flow needs. Normally this is not done when the turbo is part of the exhaust, as the backpressure and pumping losses get out of control at higher revs and boost. In the case of using superheated steam, these are not concerns. I'm thinking of like a turbine side from a 40 series turbo on a compressor side of a 70 series. The result I'm thinking will be I'd need only a little mass flow, but I'd be seeing 60-80psi steam pressure on the inlet to the turbo, which shouldn't be a problem.

The big question is, how much more effective is steam + a little CO2 (from the propane combustion), than typical exhaust gasses? Will I need just as much mass flow? Or will the steam drive the turbine much more efficiently than exhaust gasses would?

At this point, it's a matter of consumption. It will work for sure, but can I get away with as little as 10lb/min steam, or will I need to produce 50-60lb/min? This is to support a engine mass airflow rate of 60-70lb/min.

 

[Razor]

I see your idea, the question is why?

Are you thinking of making like a beltless supercharger? And due to the mounting, bracketry, fueling control, etc.. hence my original question.

Could it, will it work..sure.. very plausible, you still will need to exhuast the gasses from igniting the charge.

Beyond my current knowledge base on your question for sizing..Good luck with the theory

 

[denn454]

thats a new idea, but how much of your fuel would it take to spin a turbo? and then keep it spinning. I think it might be able to help out with less back pressure on the engine, but that might be offset by the effency of your fuel system thing.

one thing i think would work great would be to make an entirerly new turbo, with 2 turbine housings, the outer one woudl be for exhaust gasses like normal the middle one would be for your fuel thing. it could be ran off throttle position for near instant spool up.


I had an idea sortof like that before. take a big bov and have it empty into a pressure tank everytime you let off the throttle, then everytime you hit the throttle it releases that air back into either the eigine or the exhaust wheel to eleminate lag.

another idea i had, this one is a little far out there. you take a turbo and supercharger and combind the two. use a one way bearing on the shaft to act as a supercharger, once the exhaust gasses spin the turbine fast enough it "outruns" the belt and then acts like a turbo. blower spins at 30,000 rpm and a turbo spins at what, 100,000 rpm, its obvious how much better a turbo CAN work. the extra friction and weight would probably make it completely usuless but its still an idea right.

sorry to steal your thread, new ideas are the only way to get faster.

 

[1badTTA]

And then there are the electric turbochargers (not the ones on e-bay) that have an electric motor to spool it up instantly and then the exhaust makes the power. Another idea that never materialized due to the size of the electric motor required.

 

[denn454]

electric huh? if your still running through the exhaust to make power how yould you protect the parts of the motor from the extreme heat? thats the biggest problem i could see there.

even those electric ones on ebay don't sound all that bad when you think about it. first off its realy a supercharger. electric powered coolant fans are a huge improvement over the fans connected to the eigine. electric powered water pumps are in some cases better than the belt driven ones. see where i'm going. with the right motor an electric supercharger could be better than a belt driven one. I don't know if there is a motor that can make the torque at the kinds of rpm it would have to run at to work as good as a belt driven blower. if not now, in 5-10 years the technolegy will be out there. thoes ones one ebay are a joke right now, but who knows they might make their way into something respectable.

I really do likie the gas idea as an adition to the normal turbo we all know and love.

 

[V6DVette]

I don't know if there is a motor that can make the torque at the kinds of rpm it would have to run at to work as good as a belt driven blower. if not now, in 5-10 years the technolegy will be out there. thoes ones one ebay are a joke right now, but who knows they might make their way into something respectable.

A few years ago I was at a seminar and the instructor passed around a 15 HP electric motor that was about half the size of a beer can. Spun @ 10,000 RPM if I remember right. It was out of an F-16. The technology is out there...Just needs to filter down to us.


I'm never gonna finish this car!

 

[Turbo-Rich]

Something sort of like this is already being done.

An "on demand" only turbocharger only it's being ran completely off C02. I believe it's called the Terminator system & has been in developement for a while now. It's not as easy as hooking up a C02 line to a turbine housing but I hear it works amazingly well.

 

[AnArKey]

Well that's interesting. Nothing but CO2 eh? I supposed that would work, but would require a TOTALLY different approach to turbine design. You would want a super small turbine wheel and housing, with lots of tighly packed fins. You would want tons of backpressure in the entrance to the turbine, to catch all the power of expansion of the CO2.

I wonder how well they got it down. If the CO2 consumption rate could be kept low enough, it would work fantastic.

Any links, data you can share?

 

[Turbo-Rich]

Sorry, no web sites YET.
There is a tech/newsgroup deadicated to it but is currenly closed to the public. Too many nay~sayers & flamers.


Your definately on the right track with your tthinking of how it could work. Small turbine housings are being used but of the junkyaard turbo variety. No one I know of is designing thier own wheels. This techknology is definatley in its infancy.
C02 can POTENTIAALLY produce 3,000 psi of pressure when correctly manipulated buts its real power has seeminly been its tremendous amount of expansion. Plenty of VOLUME can be easily made to drive the turbine.
From what I've seen the actual C02 consumption rate is very minimal.


P.S. C02 also makes one AWSOME pre-spooler

 

[AnArKey]

You email me the info on that group perhaps? Maybe they will let me in, I'm sure I add to the discussion.

 

[Dubwho]

I've bought old ****'s book "21st Century Turbocharging" which makes a good brainstorming provoker. He's one of the people involved in the "Terminator" experiment. His website, www.gatorsuperchargers.com talks about his homemade supercharger and shows links to some chat rooms. I like the "Terminator" idea too and I am coming up with some original thoughts based on a co2 powered air motor. The Terminator is simply a large turbo compressor coupled to an air motor, die grinder perhaps. Connect it inline with your turbo/super setup for compound pressure building. If you run the co2 thru a "co2 to air cooler" before going to the air motor, it can also drop intake temps. You'll need an oiler before the air motor to keep it lubed!

PS, injecting co2 at your compressor wheel to make a pre-spooler, works, but how long can a fire red compressor wheel take a freezing blast of co2? Just like spraying your header with a garden hose after a hot run.

 

[Dubwho]

I like how this forum blocked out Richard's name when I used his nickname.

He goes by D_ck, so what was I to write?

 

[postal]

I've bought old ****'s book "21st Century Turbocharging" which makes a good brainstorming provoker. He's one of the people involved in the "Terminator" experiment. His website, www.gatorsuperchargers.com talks about his homemade supercharger and shows links to some chat rooms. I like the "Terminator" idea too and I am coming up with some original thoughts based on a co2 powered air motor. The Terminator is simply a large turbo compressor coupled to an air motor, die grinder perhaps. Connect it inline with your turbo/super setup for compound pressure building. If you run the co2 thru a "co2 to air cooler" before going to the air motor, it can also drop intake temps. You'll need an oiler before the air motor to keep it lubed!

I bought that dudes book also. First and foremost he is a ****ing moron a concieted moron. He makes so many stupid statements in his book that you want to find him and slap him upside the head. But even ****ing morons can have an idea or two.

For the original idea of no turbo in the exhaust steam: I read a book multiple times about ten years ago. The authors name slips my mind, i think its was McInnes or some thing like that. The guy was some big engineer that did alot in the field. Anyways in that book he said a properly designed turbo set up will have 2 to 3 times the amount of pressure in the exhaust manifold as boost. So your talking like 90 psi back pressure for 30 psi boost! I believe this book was old 10 years ago I have always wanted to mount a pressure gauge to pre turbo exhaust to see what it reads. He says this is way turbo motors dont like big cams. Big cams have both intake and exhaust valves open at the same time (overlap) and since exhaust pressure is a couple times higher than intake manifold pressure you get flow in the wrong direction. This leads me to think removing exhaust back pressure completely would have a substantial increase in hp especially if you then went to a true hipo camshaft which for a 6k rpm motor would be more like 240 degrees duration at 050" instead os 208 to 218 like most gn guys run.

Here is one of the problems I see with your idea: The vortek superchargers and the like are basically a turbocharger style centrifugal compressor that’s mechanically driven. These guys wind up having to keep a close eye on them belts to drive those things. They take a lot of hp to turn. It takes a lot of power to pump and compress enough air to feed a hipo forced induction motor. The more power the motor makes the more power needed to drive that damn compressor. It is a lot! It can take a couple hundred hp to drive the damn thing. I'm straining my brain here but I think on a 400hp motor your talking like 50 to 100hp to drive the compressor. Now keep in mind that cetrifugal compressors (like on turbos) are actually pretty darn efficient for the flow and pressure we need, thats why they work good. If the "efficient" compressor needs approximately 100hp to drive it to feed this motor. Then aren't you going to have to come up with 100 hp from your turbine side?? How much steam are you going to have to make? How the hell you going to make that much steam? Where are you going to dump all this water vapor? I'm tired of typing so I'm going to stop here for now.

HTH: Jason

 

[postal]

OK you got me fired up so I'm going to ramble just a bit more.

What about compressed air. Not to drive any thing but to spray into the up pipe. Lets say you supplied 10% of the air needed to power the motor for a pass. Now wouldnt that be 10% less air that the turbo needed to pump and compress? Wouldnt the back pressure go down do to less turbine power needed to drive the compressor? IF you have a air tank at room temp and 150psi isnt the temp going to be nice and cold at the 20 to 30 psi you regulate it down to for spraying into the up pipe (free intercooling)? Boost isnt how much air is going through your motor its the "extra" air builing up in the intake. Lets say 10% is 70cfm, well that 70cmf might be closer to an extra 50% when your first spooling up. That will be a major kick in the ass for spool up. Will the extra 10% of air now make a 44 act like a 63 and a 63 now act like a 70 for top end and yet do the complete opposite for spool up? Whos going to help you get the fuel right . DONT ASK ME . Actually Ive been wanting to talk to Mike Licht at fullthrottle about an idea or two about fueling mods with a translator set up There might be a means there to get a crazy idea or two to the test stage.

HTH: Jason

HTH: Jason

 

[JDEstill]

Here is one of the problems I see with your idea:

That is exactly right Jason. The compressor does take that much power to turn, and that power has to come from somewhere. For the desired flow and pressure that AnArKey gave in a similar thread in the Turbo section, 120 hp is required.

That power gets sucked right off the crank if it was a Vortec, Paxton, etc... (taking it away from power going to the wheels, which is why turbos can ultimately make more power than superchargers).

Or it gets extracted from the exhaust in a typical turbo car. Or, in the case of this idea we are discussing, it gets extracted from steam or CO2 or whatever.

If the compressor was powered with an electric motor, the 120 hp would have to ultimately be supplied by the battery/alternator. I'm guessing that to get 120 hp worth of electricity out of an alternator, you have to put at least 130 hp into it, which again would come right off the crank.

Nothing wrong with using stored energy via a bottle of CO2, etc for powering the turbine. I do think that the amounts required have been underestimated so far. You can compensate for lower flow rates with higher inlet pressures to some extent, but it isn't infinite - you can't have some super high pressure and super low flow and still get the power needed out of the turbine.

But if someone gets it all worked out, that would be a nice plus. The backpressure is the only real penalty to a turbocharger. It essentially reduces air flow by leaving more exhaust in the cylinder after the exhaust valve closes, and that takes up room that could be used for fresh air/fuel. Getting rid of the backpressure would make for some nice gains... how much, I'm not sure. I'd guess... 15-20% more hp?

With regard to your compressed air idea Jason, sounds good with one caveat: the compressed air being let down into the uppipe will not get super cold like nitrous or CO2 will. Bottles of those substances are stored as liquids, and it is the liquid evaporating as it gets let down that makes it really cold. An air tank like you describe would just be full of compressed gas, and while it will cool down a little, it'll be more like 10 degrees or something - not that big a deal.

As for backpressure, I'm like you - one of these days I'm going to get around to measuring mine. The guys I know who have ended up with pressures in the 25-40 psi range if I remember right. I think more people should do this. If the ratio of boost pressure to exhaust pressure starts getting too high, its a sign that you need a bigger turbine housing and/or wheel, such as going from a 0.63 housing to a 0.82.

John

 

[redhotrod]

anyone try injecting pure oxygen from like a welding tank?

 

[V6DVette]

Originally posted by redhotrod
anyone try injecting pure oxygen from like a welding tank?

NOT a good idea...Can you say "melt down"?
Ever see someone cut metal with a torch? They heat the metal up and then add a blast of oxygen. It causes the metal to burn. Same thing would happen in your motor.




I'm never gonna finish this car!

 

[JDEstill]

I don't think it would torch the innards of your engine. I think it would be like nitrous, but more so... however much fuel you have to inject with a given nitrous shot, you'd probably have to inject ~3 times that amount for an equivalent O2 shot. And you'd get about 3X the power too!

That being said, it would be a big safety hazard. Any kind of accident and you'd really go up in flames. Think space program, that accident on one of the Apollo missions that killed the 3 astronauts. Stuff that wouldn't normally burn will go up like a torch in a pure oxygen environment.

John

 

[racemybuick]

I am looking at your idea in a maintenance perspective...First of all, you'll probably need a black seal high pressure liscence to operate it. It sounds to me like a miniature boiler under the hood of your car. Yeah, you have unlimited HP capabilities, however, with the amount of heat and the amount of weight you add with the equipment, I think the turbo remians the lesser of the two evils. You can keep a turbo light weight, and fully compatible with the motor. It is low pressure, 600 cfm, or 16 psi. You system, as stated before, prolly would push 40-60 range. That is a lot of pressure on the heads.
a model engine mechanic would have a field day with this idea. ANd eventually, someone mechanically inclined enough, could develop your idea! But until it is done, it doesnt seem plausible. Good luck, awsome topic!!!

John

 

[AnArKey]

Still pondering the idea. I don't know why I didn't say it initially, but my temp idea was off. Rather, the hotter, the better. It's all about VOLUME through the turbo, not mass. At 1500F, steam has about 57% more volume than air. It gets better the hotter you go. To get the steam hotter, you add less water, which improves combustion. By keeping it over the autoignition temperature of propane (975F) I think I understand things enough now to say with confindence that combustion will be achievable and maintained. I know superheated steam can cause fires very easily. Once it's no longer "wet," H20 is no longer inherently a combustion killer.

I'd probably want a inconel turbine, like I said, the hotter, the better, until you roast the turbo. I have read you can run 2000F temps through them, which would be good if it's true. I'd probably heat coat the inside of the pipe and turbine.

There need not be a combustion chamber of any major size. Just a 4" diameter by 12" long tube, necking down to the turbine inlet. Three means of injection (propane, oxygen, water), some means of ignition, and that's it. Probably want to use titanium for the combustion chamber so I don't melt holes in it.

I have a spreadsheet doing the math for energy in, and as far as I can tell, I should be able to pull this off with 1-2GPM water flow, and 3-4lb/min oxygen flow. Propane will be miniscule at under 1lb/min, and since the car will likely be running on propane anyway, it will serve a dual function.

The experiment for this will be impressive. It will basically be a superheated steam thrower. Probably worse than flame if used on a person.