banner
banner

19 Mar 2024, 07:46 [ UTC - 5; DST ]


Aviation Fabricators (Top Banner)



Reply to topic  [ 67 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next
Username Protected Message
 Post subject: Re: Small Turbines
PostPosted: 25 Apr 2017, 22:28 
Offline




User avatar
 Profile




Joined: 12/10/07
Posts: 30319
Post Likes: +10476
Location: Minneapolis, MN (KFCM)
Aircraft: 1970 Baron B55
Username Protected wrote:
This is the technology that has a chance to completely change the game.

Turbine power/weight ratio and better efficiency than diesel. It's not pie in the sky, either, these guys are real scientists and engineers and have already demonstrated the potential. The simplicity of the engine should lead, eventually, to high reliability as well, which is what's needed for an aviation power plant.

It's a few years out, though.

Nathan


It has been a few years out for a long time. Basically, the "inventor" inverted a traditional wankel rotary engine. The end result is he likely will run into the same issues all rotary engines have: seals and efficiency.

Tim

That's my take as well. It also looks like a low RPM, high displacement configuration wouldn't be feasible (just like the Wankel) so a reduction system would be needed as well.
_________________
-lance

It's easier to fool people than to convince them that they have been fooled.


Top

 Post subject: Re: Small Turbines
PostPosted: 26 Apr 2017, 05:03 
Offline



User avatar
 Profile




Joined: 10/05/11
Posts: 9542
Post Likes: +6384
Company: Power/mation
Location: Milwaukee, WI (KMKE)
Aircraft: 1963 Debonair B33
Liquid Piston doesn't seem to have apex seals like a wankel. It appears to be a little "Bourke-like" in the attempt to hold a constant volume during combustion.

Not sure how it would be lubricated or sealed, though.

I also wonder about piston heat since exhaust and intake share that "wall" in the piston.

I love all of these alternative engine guys. All a little crazy and hope springs eternal. One day one will work.

_________________
Be Nice


Top

 Post subject: Re: Small Turbines
PostPosted: 26 Apr 2017, 07:10 
Offline


 Profile




Joined: 11/24/11
Posts: 76
Post Likes: +33
Aircraft: Mitsubishi Solitaire
Liquid Piston isn't a Wankel. The LP engine uses a different thermodynamic cycle with constant volume combustion. That allows a much higher compression ratio, which is one important measure of engine potential. The architecture allows the seals to be on the housing, not the rotor, which solves many issues.

Their first real application (second stage funding through DARPA) is air cooled.

These guys are real, not cranks. A father/son team of MIT PhDs. They've convinced some of the smartest people I know to invest. I've thought about it myself. Implementation is always a challenge, but they've demonstrated the basic principles to my satisfaction, and it's the first truly new engine technology I've seen in a while.

Nathan


Top

 Post subject: Re: Small Turbines
PostPosted: 26 Apr 2017, 07:24 
Offline


User avatar
 Profile




Joined: 11/06/10
Posts: 11879
Post Likes: +2846
Company: Looking
Location: Outside Boston, or some hotel somewhere
Aircraft: None
Username Protected wrote:
Liquid Piston isn't a Wankel. The LP engine uses a different thermodynamic cycle with constant volume combustion. That allows a much higher compression ratio, which is one important measure of engine potential. The architecture allows the seals to be on the housing, not the rotor, which solves many issues.

Their first real application (second stage funding through DARPA) is air cooled.

These guys are real, not cranks. A father/son team of MIT PhDs. They've convinced some of the smartest people I know to invest. I've thought about it myself. Implementation is always a challenge, but they've demonstrated the basic principles to my satisfaction, and it's the first truly new engine technology I've seen in a while.

Nathan


Cool. I wish them luck.

Tim


Top

 Post subject: Re: Small Turbines
PostPosted: 26 Apr 2017, 14:29 
Offline


User avatar
 Profile




Joined: 11/08/13
Posts: 1898
Post Likes: +1159
Location: KCRQ
Aircraft: Breeezy, 182,601P
With the advent of 3D printing one can now design things that have integral cooling passages that could not have been possibly made by any other means.

This means that one can have high temperature (hastaloy) parts with internal cooling passages, that are in shapes and configurations that were up to now impossible to fabricate.

This should allow true innovation in engine processes and architectures to blossom and flourish...


Top

 Post subject: Re: Small Turbines
PostPosted: 26 Apr 2017, 15:14 
Offline


User avatar
 Profile




Joined: 08/26/15
Posts: 9513
Post Likes: +8743
Company: airlines (*CRJ,A320)
Location: Florida panhandle
Aircraft: Travel Air,T-6B,etc*
Username Protected wrote:
With the advent of 3D printing one can now design things that have integral cooling passages that could not have been possibly made by any other means.

Maybe, maybe not... but I'd love to see it happen. We're talking extremely fine production tolerances and highly stressed components. Single-crystal has been the "best" way to produce turbine blades for the last twenty years.

On the other hand, googling "3D printing nickel superalloy" turns up a lot of really promising stuff! :cross:


Top

 Post subject: Re: Small Turbines
PostPosted: 26 Apr 2017, 15:22 
Online


 Profile




Joined: 11/22/08
Posts: 2909
Post Likes: +919
Company: USAF Propulsion Laboratory
Location: Dayton, OH
Aircraft: PA24, AEST 680, 421
Username Protected wrote:
With the advent of 3D printing one can now design things that have integral cooling passages that could not have been possibly made by any other means.

This means that one can have high temperature (hastaloy) parts with internal cooling passages, that are in shapes and configurations that were up to now impossible to fabricate.

This should allow true innovation in engine processes and architectures to blossom and flourish...

3D printing is allowing us to make complex heat exchangers for recuperated engines. That is one of the technologies we are looking at. Whether they can actually save enough weight and volume is another question. Could be promising.


Top

 Post subject: Re: Small Turbines
PostPosted: 26 Apr 2017, 15:22 
Offline


User avatar
 Profile




Joined: 11/06/10
Posts: 11879
Post Likes: +2846
Company: Looking
Location: Outside Boston, or some hotel somewhere
Aircraft: None
Username Protected wrote:
With the advent of 3D printing one can now design things that have integral cooling passages that could not have been possibly made by any other means.

Maybe, maybe not... but I'd love to see it happen. We're talking extremely fine production tolerances and highly stressed components. Single-crystal has been the "best" way to produce turbine blades for the last twenty years.

On the other hand, googling "3D printing nickel superalloy" turns up a lot of really promising stuff! :cross:


I would think less important for the blades, more critical for the housing. With the blades, where would you route the heat too? with the housing you could route it to a regeneration system to preheat the air before the ignition.

Tim

Top

 Post subject: Re: Small Turbines
PostPosted: 26 Apr 2017, 15:24 
Online


 Profile




Joined: 11/22/08
Posts: 2909
Post Likes: +919
Company: USAF Propulsion Laboratory
Location: Dayton, OH
Aircraft: PA24, AEST 680, 421
Rotary detonation engines/combustors have been making a lot of progress. Allows constant volume combustion and alleviates some of the issues with small clearances required for conventional turbo machinery.


Top

 Post subject: Re: Small Turbines
PostPosted: 26 Apr 2017, 15:30 
Offline


 Profile




Joined: 01/01/11
Posts: 964
Post Likes: +599
Company: Well, it's UA now
Location: Houston, TX
Aircraft: B-787 & C55
Username Protected wrote:

I would think less important for the blades, more critical for the housing. With the blades, where would you route the heat too? with the housing you could route it to a regeneration system to preheat the air before the ignition.

Tim


The heat would go out the tailpipe. Take a look at this picture and you can see that the blade is cooled inside out. Pressurized air is routed up the inside/middle of the blade and then out the holes that you see. The blade needs to be cooled for fatigue and stretch/creep issues. The housing, burner and tailpipe area have bypass air running over them for cooling as well as oil cooling for the inside of the case and bearing surfaces. In the case of the burner there is bypass/non combustion air flowing over the surface both inside and outside to keep it cool enough to do its job.

By cooling the turbine blades better you can extract more energy from the combustion process by moving the turbine section closer to the combustion area or running the combustion area hotter.


Image

Image

Image


Last edited on 26 Apr 2017, 15:50, edited 1 time in total.

Top

 Post subject: Re: Small Turbines
PostPosted: 26 Apr 2017, 15:49 
Offline


User avatar
 Profile




Joined: 11/06/10
Posts: 11879
Post Likes: +2846
Company: Looking
Location: Outside Boston, or some hotel somewhere
Aircraft: None
Username Protected wrote:

I would think less important for the blades, more critical for the housing. With the blades, where would you route the heat too? with the housing you could route it to a regeneration system to preheat the air before the ignition.

Tim


The heat would go out the tailpipe. Take a look at this picture (link below) and you can see that the blade is cooled inside out. Pressurized air is routed up the inside/middle of the blade and then out the holes that you see. The blade needs to be cooled for fatigue and stretch/creep issues. The housing, burner and tailpipe area have bypass air running over them for cooling as well as oil cooling for the inside of the case and bearing surfaces. In the case of the burner there is bypass/non combustion air flowing over the surface both inside and outside to keep it cool enough to do its job.

By cooling the turbine blades better you can extract more energy from the combustion process by moving the turbine section closer to the combustion area or running the combustion area hotter.

http://www.me.umn.edu/labs/tcht/measurements/what.html

Image

Image

Image


That is cool. literally...


Tim

Top

 Post subject: Re: Small Turbines
PostPosted: 27 Apr 2017, 09:25 
Offline


User avatar
 Profile




Joined: 12/17/10
Posts: 1611
Post Likes: +272
Location: Valparaiso, IN
Aircraft: Lancair Evolution
What I'd like to see out of these small turbines is something that would be in the 250hp range at the mid to upper teens. Something that's 200hp at sea level probably won't be able to perform very well by the time you get over 12k.

Then again, what do I know. Maybe they hold their power better than a TN-550?


Top

 Post subject: Re: Small Turbines
PostPosted: 27 Apr 2017, 11:39 
Offline


User avatar
 Profile




Joined: 08/26/15
Posts: 9513
Post Likes: +8743
Company: airlines (*CRJ,A320)
Location: Florida panhandle
Aircraft: Travel Air,T-6B,etc*
Something else about scalability and small turbines, complicated cooling passages--especially ones for film cooling--in turbine blades does not scale down well. The tip gap tolerance isn't the only technical challenge but those cooling passages too. It's a bit like the differences between drawing a complicated picture on a pad of paper or drawing the same picture on a postage stamp- no matter what tricks you have up your sleeve, the small stamp will always be more challenging.

The real kicker is the first stage turbine blades, the hottest ones in the engine that can benefit most from active cooling, are also the smallest in the engine. Each successive stage's blades are a little bit bigger than the last, and the hot gases might cool off by a hundred degrees or hundreds of degrees as they expand through each stage.


Top

 Post subject: Re: Small Turbines
PostPosted: 27 Apr 2017, 12:27 
Offline



User avatar
 Profile




Joined: 10/05/11
Posts: 9542
Post Likes: +6384
Company: Power/mation
Location: Milwaukee, WI (KMKE)
Aircraft: 1963 Debonair B33
Username Protected wrote:
Something else about scalability and small turbines, complicated cooling passages--especially ones for film cooling--in turbine blades does not scale down well. The tip gap tolerance isn't the only technical challenge but those cooling passages too. It's a bit like the differences between drawing a complicated picture on a pad of paper or drawing the same picture on a postage stamp- no matter what tricks you have up your sleeve, the small stamp will always be more challenging.

The real kicker is the first stage turbine blades, the hottest ones in the engine that can benefit most from active cooling, are also the smallest in the engine. Each successive stage's blades are a little bit bigger than the last, and the hot gases might cool off by a hundred degrees or hundreds of degrees as they expand through each stage.


That makes a lot of sense, too. Thanks.

I wonder if there are other or different ways to think about cooling the turbine blades on a smaller unit. Sure seems like 3D printing could accommodate the passages, but I guess that materials are not there yet.

_________________
Be Nice


Top

 Post subject: Re: Small Turbines
PostPosted: 27 Apr 2017, 13:22 
Offline


User avatar
 Profile




Joined: 11/06/10
Posts: 11879
Post Likes: +2846
Company: Looking
Location: Outside Boston, or some hotel somewhere
Aircraft: None
Username Protected wrote:
That makes a lot of sense, too. Thanks.

I wonder if there are other or different ways to think about cooling the turbine blades on a smaller unit. Sure seems like 3D printing could accommodate the passages, but I guess that materials are not there yet.


When I was reading up on film cooling (earlier in the thread), I found a really interesting prototype NASA concept engine. Used two methods of cooling the blades, one was preheating the fuel by running it through the blades, second was releasing a thin stream of water along the leading edge instead of air. The water instantly vaporizes as steam, and created a large and more consistent airfoil shape with less penalty. As a result they were able to increase the combustion temp by a significant margin over film cooling. The downsides were the weight of the water, and the corrosion was really bad. Oh well, nothing is free...

Tim


Top

Display posts from previous:  Sort by  
Reply to topic  [ 67 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next



Concorde Battery (banner)

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  

Terms of Service | Forum FAQ | Contact Us

BeechTalk, LLC is the quintessential Beechcraft Owners & Pilots Group providing a forum for the discussion of technical, practical, and entertaining issues relating to all Beech aircraft. These include the Bonanza (both V-tail and straight-tail models), Baron, Debonair, Duke, Twin Bonanza, King Air, Sierra, Skipper, Sport, Sundowner, Musketeer, Travel Air, Starship, Queen Air, BeechJet, and Premier lines of airplanes, turboprops, and turbojets.

BeechTalk, LLC is not affiliated or endorsed by the Beechcraft Corporation, its subsidiaries, or affiliates. Beechcraft™, King Air™, and Travel Air™ are the registered trademarks of the Beechcraft Corporation.

Copyright© BeechTalk, LLC 2007-2024

.bullardaviation-85x50-2.jpg.
.daytona.jpg.
.aircraftassociates-85x50.png.
.cjx-85x50.jpg.
.ssv-85x50-2023-12-17.jpg.
.Marsh.jpg.
.Genesys_85x50.jpg.
.blackhawk-85x100-2019-09-25.jpg.
.tat-85x100.png.
.bpt-85x50-2019-07-27.jpg.
.avionwealth-85x50.png.
.aeroled-85x50-2022-12-06.jpg.
.pure-medical-85x150.png.
.headsetsetc_Small_85x50.jpg.
.SCA.jpg.
.jetacq-85x50.jpg.
.Wingman 85x50.png.
.MountainAirframe.jpg.
.stanmusikame-85x50.jpg.
.wilco-85x100.png.
.pdi-85x50.jpg.
.CiESVer2.jpg.
.gallagher_85x50.jpg.
.planelogix-85x100-2015-04-15.jpg.
.camguard.jpg.
.saint-85x50.jpg.
.kingairacademy-85x100.png.
.wat-85x50.jpg.
.shortnnumbers-85x100.png.
.aircraftferry-85x50.jpg.
.cav-85x50.jpg.
.jandsaviation-85x50.jpg.
.geebee-85x50.jpg.
.kadex-85x50.jpg.
.tempest.jpg.
.AAI.jpg.
.chairmanaviation-85x50.jpg.
.dbm.jpg.
.lucysaviation-85x50.png.
.sierratrax-85x50.png.
.Foreflight_85x50_color.png.
.airmart-85x150.png.
.ei-85x150.jpg.
.aviationdesigndouble.jpg.
.centex-85x50.jpg.
.one-mile-up-85x100.png.
.traceaviation-85x150.png.
.kingairnation-85x50.png.
.Wentworth_85x100.JPG.
.midwest2.jpg.
.Rocky-Mountain-Turbine-85x100.jpg.
.ABS-85x100.jpg.
.temple-85x100-2015-02-23.jpg.
.concorde.jpg.
.blackwell-85x50.png.
.Latitude.jpg.
.boomerang-85x50-2023-12-17.png.