Axial Flow Supercharger
12-07-2004, 10:55 PM
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Richard,
You got suckered into that one. Got to roll with those punchs. E-shaft versus crankshaft. It's subtle how those words slip off the tongue.
Not to poke too much fun but most gas turbine designs are trying to get stage counts down in recent designs (they cost too much money to make). However, at the same time, they are trying to push up pressure ratios and improve efficiencies. I think you may have been a bit generous in your claims on efficiency for most gas turbine compressor designs. In most cases it is a battle to get much above polytropic compressor efficiencies above 92%. As you point out, most gas turbines operate between 50-60% and 100% gas generator speeds instead of the 10-to-100% speed that you are designing for. Obviously, the extended range of operation will require special care.
One of the items I'm most interested in is the boost profile versus speed. In order to make a reasonable amount of power/torque at low to mid range engine speeds, you will need to be able to get the supercharger speeds up quickly. Have you considered outlandish ideas like a form of constant velocity drive to keep the supercharger speed up at low speeds???
For the individual that indicated that a broken blade from a axial flow super charger wouldn't cause some additional damage as it passed down stream. I'm sorry but that is extremely unlikely. Anything that travels through one of these engines that shouldn't is going to make hardware very unhappy. However, Richard has indicated that he has designed this to minimize the likelihood that you will eat these parts. Just don't leave loose parts/tools in front of this beast. They make very good vacuum cleaners
You got suckered into that one. Got to roll with those punchs. E-shaft versus crankshaft. It's subtle how those words slip off the tongue.
Not to poke too much fun but most gas turbine designs are trying to get stage counts down in recent designs (they cost too much money to make). However, at the same time, they are trying to push up pressure ratios and improve efficiencies. I think you may have been a bit generous in your claims on efficiency for most gas turbine compressor designs. In most cases it is a battle to get much above polytropic compressor efficiencies above 92%. As you point out, most gas turbines operate between 50-60% and 100% gas generator speeds instead of the 10-to-100% speed that you are designing for. Obviously, the extended range of operation will require special care.
One of the items I'm most interested in is the boost profile versus speed. In order to make a reasonable amount of power/torque at low to mid range engine speeds, you will need to be able to get the supercharger speeds up quickly. Have you considered outlandish ideas like a form of constant velocity drive to keep the supercharger speed up at low speeds???
For the individual that indicated that a broken blade from a axial flow super charger wouldn't cause some additional damage as it passed down stream. I'm sorry but that is extremely unlikely. Anything that travels through one of these engines that shouldn't is going to make hardware very unhappy. However, Richard has indicated that he has designed this to minimize the likelihood that you will eat these parts. Just don't leave loose parts/tools in front of this beast. They make very good vacuum cleaners
12-07-2004, 11:41 PM
#903
Nice to hear from Turbine again. Well I said I have been out of touch on modern trends in the real world. I kinda stay here in my own bat cave.
As to my curve we still have to finalize the production version. Also my test bench isn't the most up to date equiped. Getting data to the inth degree isn't available.
But I think as on the V-8 units we will pass the engine output below half speed when limited to the same top Pr. Then give almost twice the final additional power. I have to get that test sheet scaned in.
I think that the post addressing failed blading was a misunderstanding from something I said. While I stated the saftey factor for failure they may have thought that to mean something else. What I said on another post was to the effect of when we did fail one the blades went through without major damage. What happened on that one is a lot of blades went all the way through the engine but a couple stuck under the valves. It only took pulling the heads and fixing those two valves. The blower?? Oh yes it was of course was scrap. So just don't drop a 10-32 nut into the intake.
What happened to the nut?? Don't know, it never showed up again.
Then these new units are cut from billet while the old ones were investment cast. The new ones will be more mallable. It will still ruin the compressor section if you eat something like a nut but it may not loose the blades. Then again you may not have the luck of the nut going right through. That one may be once in a liftime.
Now that I think about the rotary has a better chance in these cases. Still it is not a negative compared to other blowers because they can't eat things any better. Lets see, the centrifugal might have the best chance, the screw the least on a par with the roots. Just try not to do it.
About that CVT, at one time ZF in Germany experimented with such an item of a size we could use. I never got into direct talks with them but there was some flirting. Problem was it costs as much or more then the blower itself. It would be nice to make that thing computer controled for speed rather than constant. It would be the final answer if we could do it that way.
The ECU could actually control the power output on demand. Nah, life will never be that good.
As to my curve we still have to finalize the production version. Also my test bench isn't the most up to date equiped. Getting data to the inth degree isn't available.
But I think as on the V-8 units we will pass the engine output below half speed when limited to the same top Pr. Then give almost twice the final additional power. I have to get that test sheet scaned in.
I think that the post addressing failed blading was a misunderstanding from something I said. While I stated the saftey factor for failure they may have thought that to mean something else. What I said on another post was to the effect of when we did fail one the blades went through without major damage. What happened on that one is a lot of blades went all the way through the engine but a couple stuck under the valves. It only took pulling the heads and fixing those two valves. The blower?? Oh yes it was of course was scrap. So just don't drop a 10-32 nut into the intake.
What happened to the nut?? Don't know, it never showed up again.
Then these new units are cut from billet while the old ones were investment cast. The new ones will be more mallable. It will still ruin the compressor section if you eat something like a nut but it may not loose the blades. Then again you may not have the luck of the nut going right through. That one may be once in a liftime.
Now that I think about the rotary has a better chance in these cases. Still it is not a negative compared to other blowers because they can't eat things any better. Lets see, the centrifugal might have the best chance, the screw the least on a par with the roots. Just try not to do it.
About that CVT, at one time ZF in Germany experimented with such an item of a size we could use. I never got into direct talks with them but there was some flirting. Problem was it costs as much or more then the blower itself. It would be nice to make that thing computer controled for speed rather than constant. It would be the final answer if we could do it that way.
The ECU could actually control the power output on demand. Nah, life will never be that good.
Last edited by Richard Paul; 12-07-2004 at 11:53 PM.
12-08-2004, 12:14 AM
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RP, when you mentioned that the 5-stage makes more power than can be used in stock configuration, was this statement the result of specific problems with the "host" car?
If so, which components were the "weakest link", and how?
If not, did you mean that upgrades would be needed, like maybe an intercooler?
Also what kinds of obstacles are there towards developing a cvt-afs if cost were not a factor?
If so, which components were the "weakest link", and how?
If not, did you mean that upgrades would be needed, like maybe an intercooler?
Also what kinds of obstacles are there towards developing a cvt-afs if cost were not a factor?
12-08-2004, 01:09 AM
#905
There is no simple answer to your question. What keeps the boost down is several things, among them heat and fuel system headroom. It seems that Mazda gave the RX 8 a less then optimum cat. There are better cats that can take the higher temp but they cost more and in normal condition the one supplied works fine, so it would have been a extra expense not needed.
For the few owners who need the higher temp cat they figure they can take care of themselves. Every degree of temp that goes in carries all the way through. So if they only have a 150 degree saftey factor then that is a limit to your added intake temp. Now I'm not saying that number is what we are talking about I only said that to throw out a number.
Next you need to have so many extra lbs of fuel for the extra air. It is unlikely that there is more then 25% extra capacity in the system. There are some tricks to play here but they don't allow much.
What fails is not just a single thing and I personaly was not one who failed an engine. I only hear about these things. While I do have some excelent input here it isn't something that I am free to disclose.
The intercooler may solve some problem but not the others. In my case I hope to go without the intercooler and all it's negatives.
It is going to take awhile for FI to balance out on these engines. Everyone is trying their own path and it will get done. The longer the car is out there the more time will be put into it. I think it will be a long time and very expensive to build a very high HP 8.
We hear about 275 HP from some tuners and I can see them hitting the fuel limit at that point. So that sounds honest. The ones that are saying 300 or more may be optimistic. The ones saying 300+ at the wheels.....what can I say.
It's just going to take time and money to get the answers.
As to the gearbox, it would be a good start to see what ZF did with it. They've done the R+D so who knows.
For the few owners who need the higher temp cat they figure they can take care of themselves. Every degree of temp that goes in carries all the way through. So if they only have a 150 degree saftey factor then that is a limit to your added intake temp. Now I'm not saying that number is what we are talking about I only said that to throw out a number.
Next you need to have so many extra lbs of fuel for the extra air. It is unlikely that there is more then 25% extra capacity in the system. There are some tricks to play here but they don't allow much.
What fails is not just a single thing and I personaly was not one who failed an engine. I only hear about these things. While I do have some excelent input here it isn't something that I am free to disclose.
The intercooler may solve some problem but not the others. In my case I hope to go without the intercooler and all it's negatives.
It is going to take awhile for FI to balance out on these engines. Everyone is trying their own path and it will get done. The longer the car is out there the more time will be put into it. I think it will be a long time and very expensive to build a very high HP 8.
We hear about 275 HP from some tuners and I can see them hitting the fuel limit at that point. So that sounds honest. The ones that are saying 300 or more may be optimistic. The ones saying 300+ at the wheels.....what can I say.
It's just going to take time and money to get the answers.
As to the gearbox, it would be a good start to see what ZF did with it. They've done the R+D so who knows.
Last edited by Richard Paul; 12-08-2004 at 01:14 AM.
12-08-2004, 10:12 PM
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gotta be careful with airflow patterns on these things. if u have a nicked blade that is not blended right (nicked for any reason, like maybe during installation), you could cause a stress fracture and the blade could crack and liberate. i have seen this happen on real jet engines before. will the assembly come as one unit so the user will not have to assemble the blade assembly? they will just have to bolt and go?
12-08-2004, 10:18 PM
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Originally Posted by ironmedic
will the assembly come as one unit so the user will not have to assemble the blade assembly? they will just have to bolt and go?
. I'm sure the finished item will be shipped in one piece....and after reading this, it will probably come assembled with anti-tamper bolts!!Gomez.
12-08-2004, 10:42 PM
#909
Even with the jigs and fixtures I have built it is hard for me to assemble them. I shouldn't say hard jusr very carfully. Every thing is of very tight tolerance. That you know. Since this is a high speed machine everything must be perfectly balanced so no "nicking" is allowed.
Since everything is CNC machined from billet then the only thing that can go wrong is density distribution. This has been a problem with some imported aluminum that others have seen on flywheels.
We only use USA produced certified aircraft grade stock. We insist on certs with every batch of aluminum that we buy.
It is only called a kit because of the other componants that need be supplied to install it.
You can look back at the first few pages of this thread for pictures of completed compressors. Along with pics of internal parts.
So, no you don't have to assemble it. I'll do it for you. And as Gomez hints to the bolts are sealed so I can tell if you play erector set with it. I would like to find an anti tamper bolt that couldn't be fooled. It's just that everytime I have come across one I think it my duty to open it.
Since everything is CNC machined from billet then the only thing that can go wrong is density distribution. This has been a problem with some imported aluminum that others have seen on flywheels.
We only use USA produced certified aircraft grade stock. We insist on certs with every batch of aluminum that we buy.
It is only called a kit because of the other componants that need be supplied to install it.
You can look back at the first few pages of this thread for pictures of completed compressors. Along with pics of internal parts.
So, no you don't have to assemble it. I'll do it for you. And as Gomez hints to the bolts are sealed so I can tell if you play erector set with it. I would like to find an anti tamper bolt that couldn't be fooled. It's just that everytime I have come across one I think it my duty to open it.
12-09-2004, 08:54 AM
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the Waterworks Board here in Birmingham, uses a bolt, that the head twists off of, thats pretty tough to get around, if you ask me.
I installed a phone system, and network at Birmingham Fasteners, the company that makes these, they opperate machines made back in the 30's that there are only like 5 or 6 left in the world, and they seem to be the only source of these bolts.
They are much too large for your application, but I'm sure that somewhere someone makes one smaller. The manufacture of them is a press mechanism, with large coils of metal, that are fed into a huge piston driven press, that pinches them off and presses them into shape.
The guys that operate these machines always seem to be missing a few fingers. :o
I installed a phone system, and network at Birmingham Fasteners, the company that makes these, they opperate machines made back in the 30's that there are only like 5 or 6 left in the world, and they seem to be the only source of these bolts.
They are much too large for your application, but I'm sure that somewhere someone makes one smaller. The manufacture of them is a press mechanism, with large coils of metal, that are fed into a huge piston driven press, that pinches them off and presses them into shape.
The guys that operate these machines always seem to be missing a few fingers. :o
12-09-2004, 10:55 AM
#911
Yes, I'm aware of those type bolts but you can't disassemble the unit for service with that. It requires you to drill the remaining peice out. This isn't practical here. In practice we usually wind up assembling and disassembling these things a couple of times before they are finalized. The rotor must be built up by itself then balanced, disassembled and built up again with it's stator.
The stator must be qualified for axial clearences with the volutes and seals, then reassembled with the rotor.
During all these operations the torque of the actual fastner to be used must be at final spec. Fun huh??
The stator must be qualified for axial clearences with the volutes and seals, then reassembled with the rotor.
During all these operations the torque of the actual fastner to be used must be at final spec. Fun huh??
12-10-2004, 09:44 AM
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Richard,
As far as I understood it, the axial flow compressor has a higher peak efficiency than a twin screw compressor.
Couldn't you therefore build an industrial compressor that requires less energy? Something like this: http://www.kaeser.com/Products_and_S...ns/default.asp
In order to reach 100 psi you'd need many more stages but you could also reduce the diameter of the axial flow compressor, since the air consumption is not quite as high as that of an engine. Or would an axial flow industrial air compressor simply be too expensive?
As far as I understood it, the axial flow compressor has a higher peak efficiency than a twin screw compressor.
Couldn't you therefore build an industrial compressor that requires less energy? Something like this: http://www.kaeser.com/Products_and_S...ns/default.asp
In order to reach 100 psi you'd need many more stages but you could also reduce the diameter of the axial flow compressor, since the air consumption is not quite as high as that of an engine. Or would an axial flow industrial air compressor simply be too expensive?
12-10-2004, 11:03 AM
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Originally Posted by Richard Paul
Yes, I'm aware of those type bolts but you can't disassemble the unit for service with that. It requires you to drill the remaining peice out. This isn't practical here. In practice we usually wind up assembling and disassembling these things a couple of times before they are finalized. The rotor must be built up by itself then balanced, disassembled and built up again with it's stator.
The stator must be qualified for axial clearences with the volutes and seals, then reassembled with the rotor.
During all these operations the torque of the actual fastner to be used must be at final spec. Fun huh??
The stator must be qualified for axial clearences with the volutes and seals, then reassembled with the rotor.
During all these operations the torque of the actual fastner to be used must be at final spec. Fun huh??
F.
12-11-2004, 02:05 PM
#917
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The tolerances are such that if it was taken apart by the owner and sent back to Richard for repair, he could tell what happened. He'd know pretty fast if the damae was from failure or tampering. The damage would be different. Remember, like the rotary engine, this unit comes apart in stages. If someone tampered with it, they'll probably damage only certain parts rather then a giant failure.
12-26-2004, 10:32 PM
#921
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So, RP...at this stage in the game, do you have an established timeframe in terms of when you feel this will be ready for production? Another 6 months? 3? 12? Just wondering...I really like the uniqueness of your product, but I'm young and impatient...may end up getting the first FI kit released.
12-26-2004, 10:39 PM
#922
I remember you saying that you are testing it. i dont care much when its gonna be done but man WOULD I LOVE AUDIO!!!!! please can some 1 more tech inclined tape record this and upload it. omg i would love that!!!
12-26-2004, 11:53 PM
#924
The only sound I could record would be on the test bench. You would get the sound of rushing air above all else. You can hear a jet in the background I guess if you listened for it but the air is all I hear. So until it is in a car your request is unanswerable.
We are looking to buy a car right now. So when we get one we will install a SC and proceed to tune it. If I had to guess it would probably be March before it is ready for real road testing and CAFE inspection. Then if we get the exemption it will be sold.
How long it takes to get the exemption is something I don't know. Anyway it will take some time to get the production line rolling. We can do that while we wait for the Gov.
We are looking to buy a car right now. So when we get one we will install a SC and proceed to tune it. If I had to guess it would probably be March before it is ready for real road testing and CAFE inspection. Then if we get the exemption it will be sold.
How long it takes to get the exemption is something I don't know. Anyway it will take some time to get the production line rolling. We can do that while we wait for the Gov.
12-26-2004, 11:57 PM
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Originally Posted by Spazm
So, RP...at this stage in the game, do you have an established timeframe in terms of when you feel this will be ready for production? Another 6 months? 3? 12? Just wondering...I really like the uniqueness of your product, but I'm young and impatient...may end up getting the first FI kit released.