6 ms·

The Jet Engines with 'Digital Twins'

85 points by M_Grey 10y ago

zellyn 10y ago
The article made it unclear what the difference between a "digital twin" and an engine-specific record is. I assume the difference is that they're building a model of some kind, but you wouldn't know that from searching for [twin] in the article.
- nullpage 10y ago
  It is some tech out of GE Digital that, from what I understand, uses sensor data + machine learning against a digital representation of the system to predict failures and tune performance. A friend of mine just recently took a job at a start-up using this technology (https://veerum.com/about/ https://veerum.com/about/), however I haven't had a chance to catch up with him and really understand how this stuff works. There is some more information here: https://www.ge.com/digital/power-digital-twin https://www.ge.com/digital/power-digital-twin https://www.ge.com/digital/blog/rise-digital-twins https://www.ge.com/digital/blog/rise-digital-twins
  - roymurdock 10y ago
    It's a part of the Predix platform offering: In large-scale systems, sensor information can be in different locations separated by great distances. For example, a pipeline system may have some assets in a central terminal as well as assets in the field miles away from the terminal - and all of these must be connected to a single asset model to monitor the health of the system as a whole. Asset data can be ingested through a REST API using files in JSON format or created using a user interface. The data is stored in a graph database that is optimal for searching hierarchies of assets. Tags that indicate pressure or temperature can be associated with each asset. These tags can then be used to bring in and associate time series data and analytics to build digital twins of a complex asset. For example, you could create an asset model that describes the logical component structure of all pumps in an organization, and then create instances of that model to represent each individual pump. Or you could create custom modeling elements that meet your unique domain needs if a particular pump has a few differences with the generic version. https://www.predix.io/services/service.html?id=1171 https://www.predix.io/services/service.html?id=1171
joshuahaglund 10y ago
> In the second module an air compressor takes air in and puts it under high pressure, which shrinks the volume of the air and allows the engine to be smaller (because compressed air takes up less space). Does this reporter know what they're talking about? I always thought compressors were an essential part of a jet engine (compression heats the air, then fuel is sprayed in which auto-ignites, expanding, and turning the turbine blades). Not just because compressed air takes up less space.
- deleted 10y ago
  [deleted]
- WalterBright 10y ago
  The compressor does not heat the air to the ignition point. The flame that is already in the engine provides the ignition, and the flame is prevented from blowing out the back by "flame holders". https://en.wikipedia.org/wiki/Flame_holder https://en.wikipedia.org/wiki/Flame_holder The ignition at engine start is done with spark plugs. The purpose of the compressor is to provide dense enough air to support combustion, and the pressure is needed to prevent the exhaust gases from blowing out the front of the engine.
  - AceyMan 10y ago
    Of tangential relevance: On the aircraft I was trained on, it was SOP to set the igniters = ON when encountering some significant amount of precipitation in flight, as a defense against a water induced snuff-out. (I forget exactly how the precip threshold was determined.) Otherwise, as parent said, the flame persists following engine start, and so the "spark plugs" (igniters) are not kept active.
  - mschuster91 10y ago
    > and the pressure is needed to prevent the exhaust gases from blowing out the front of the engine Out of curiosity: has that ever happened and how does such an event look like?
    - 10y ago
dorfsmay 10y ago
This article does a terrible job at explaining how jet engines work. Spending 10 minutes on wikipedia will give you a better idea. Do look for high vs low bypass. Jet engine s are fascinating, the theory behind them is fairly simple, but a huge challenge to make it happen in the physical world, high temperatures as mentioned but also extremely high rotational speed, which requires parts as close to perfection as possible, and very robust, hairline fractures in engines have resulted in plane crashes.
- ocfnash 10y ago
  Much of the little I know about jet engines was sparked by my reading this wonderful article: https://www.americanscientist.org/issues/pub/each-blade-a-single-crystal https://www.americanscientist.org/issues/pub/each-blade-a-si... (which happily is _not_ paywalled). In particular I learned that each blade is a single crystal! I still find this absolutely mind boggling.
  - bigiain 10y ago
    Some people learn in a more hands-on fashion... https://www.flickr.com/photos/bigiain/4081474667/in/photolist-7dECdT-5FyAEF https://www.flickr.com/photos/bigiain/4081474667/in/photolis... (not me, some local guy at a DorkBot meeting way back when...)
- azernik 10y ago
  I think it does a fairly good job - I read through it in about one minute, and (having already spent some time studying jet engine principles) think it got the essential concepts across. e.g. it doesn't use the word "bypass" but does explain the principle. In such a small amount of space and with the constraints on vocabulary/prior-knowledge assumptions of a mass audience, going into the design tradeoffs of different specific designs is overkill.
  - PhantomGremlin 10y ago
    I think it does a fairly good job Yes, I agree. I also loved that they mentioned something I think is really cool --- the gas stream is hotter than the melting point of the turbine blades, and yet the designers have found an ingenious solution.
donpdonp 10y ago
Everything I know about jet engines comes from the fantastic multi-year youtube vlog of AgentJayZ of JetCity, Canada! https://www.youtube.com/user/AgentJayZ https://www.youtube.com/user/AgentJayZ
- davidgould 10y ago
  AgentJayZ is a great resource and very entertaining.
- burntrelish1273 10y ago
  Ah... Combustors, combustor liners, vacuum-melted steel, lock-wiring... all the good bits and crazy tolerances explained. Also, reminds me of the Rolls-Royce docu: https://www.youtube.com/watch?v=UazsDDFsS7Q&list=PLFF54B91EB593DF78 https://www.youtube.com/watch?v=UazsDDFsS7Q&list=PLFF54B91EB... Pairs well with some https://youtube.com/arduinoversusevil https://youtube.com/arduinoversusevil, https://youtube.com/Abom79 https://youtube.com/Abom79 and maybe some https://youtube.com/engineerguyvideo https://youtube.com/engineerguyvideo And, if you like aviation: http://www.flywithcaptainjoe.com http://www.flywithcaptainjoe.com
agumonkey 10y ago
digital twin seems like the first start of a humonculus.
Shivetya 10y ago
the detonation engine, would is sound like a hyperactive V1?
DrScump 10y ago
I was hoping that this was about a discovery that jet engines can become quantum-entangled.
- M_Grey 10y ago
  It's all fun and games until a careless measurement causes one set of engines to be "on" and the other to be "off".
  - DrScump 10y ago
    You gotta make sure that both entangled engines don't end up on the same plane.
    - M_Grey 10y ago
      At worst... you'd go in circles. At best you'd just sort of lazily zig-zag to your destination. "Goddamn it Roger, port #2 is in a superposition of existing and not existing again!" "Calm down Wilco, just take a good hard look at her and she'll settle down."
coredog64 10y ago
> They’re so difficult to make, in fact, the companies that build aircraft don’t make their own engines. Airframe manufacturers are prohibited from doing so. The "United" in "United Airlines" harks back to when Boeing, Pratt& Whitney and an airmail company were integrated into a single company. Today, when an airline buys a commercial airliner, the airframe and engine purchases are separate even though the airframe is specific to a single engine type.
- M_Grey 10y ago
  Could they unite those elements of the industry again if given the chance, or has it moved on to just be too specialized?
  - klodolph 10y ago
    I found this discussion on Quora: https://www.quora.com/Why-are-airframes-engines-developed-manufactured-by-separate-companies-especially-on-airliners-How-did-this-symbiotic-relationship-evolve https://www.quora.com/Why-are-airframes-engines-developed-ma... And this Wikipedia article: https://en.wikipedia.org/wiki/Air_Mail_scandal https://en.wikipedia.org/wiki/Air_Mail_scandal It sounds like a combination of antitrust concerns and just the fact that airframes and engines don't have much in common.
    - M_Grey 10y ago
      That was a good read, and I agree with your conclusion.
Merad 10y ago
If you find jet engines interesting, check out AgentJayZ [0] on youtube. He runs a shop in Canada that repairs and overhauls smaller jet engines (think, Learjet size rather than 777 size). He has a mix of good videos, including a long running Q&A series. [0]: https://www.youtube.com/user/AgentJayZ https://www.youtube.com/user/AgentJayZ
davidgould 10y ago
Rolls Royce publish an excellent book "The Jet Engine" with a great deal of information about the design and manufacture of jet engines. I purchased the latest print edition and it's well worth it. However there is an online PDF of an earlier edition at http://airspot.ru/book/file/485/166837_EB161_rolls_royce_the_jet_engine_fifth_edition_gazoturbinnyy_dviga.pdf http://airspot.ru/book/file/485/166837_EB161_rolls_royce_the...
- mnw21cam 10y ago
  Oh, wow. Grew up with that book in the house (probably the first edition), and yes it is fantastic.

85 points by M_Grey 10y ago

The article made it unclear what the difference between a "digital twin" and an engine-specific record is. I assume the difference is that they're building a model of some kind, but you wouldn't know that from searching for [twin] in the article.

nullpage 10y ago
It is some tech out of GE Digital that, from what I understand, uses sensor data + machine learning against a digital representation of the system to predict failures and tune performance. A friend of mine just recently took a job at a start-up using this technology (https://veerum.com/about/ https://veerum.com/about/), however I haven't had a chance to catch up with him and really understand how this stuff works. There is some more information here: https://www.ge.com/digital/power-digital-twin https://www.ge.com/digital/power-digital-twin https://www.ge.com/digital/blog/rise-digital-twins https://www.ge.com/digital/blog/rise-digital-twins
- roymurdock 10y ago
  It's a part of the Predix platform offering: In large-scale systems, sensor information can be in different locations separated by great distances. For example, a pipeline system may have some assets in a central terminal as well as assets in the field miles away from the terminal - and all of these must be connected to a single asset model to monitor the health of the system as a whole. Asset data can be ingested through a REST API using files in JSON format or created using a user interface. The data is stored in a graph database that is optimal for searching hierarchies of assets. Tags that indicate pressure or temperature can be associated with each asset. These tags can then be used to bring in and associate time series data and analytics to build digital twins of a complex asset. For example, you could create an asset model that describes the logical component structure of all pumps in an organization, and then create instances of that model to represent each individual pump. Or you could create custom modeling elements that meet your unique domain needs if a particular pump has a few differences with the generic version. https://www.predix.io/services/service.html?id=1171 https://www.predix.io/services/service.html?id=1171

joshuahaglund 10y ago

> In the second module an air compressor takes air in and puts it under high pressure, which shrinks the volume of the air and allows the engine to be smaller (because compressed air takes up less space). Does this reporter know what they're talking about? I always thought compressors were an essential part of a jet engine (compression heats the air, then fuel is sprayed in which auto-ignites, expanding, and turning the turbine blades). Not just because compressed air takes up less space.

deleted 10y ago
[deleted]
WalterBright 10y ago
The compressor does not heat the air to the ignition point. The flame that is already in the engine provides the ignition, and the flame is prevented from blowing out the back by "flame holders". https://en.wikipedia.org/wiki/Flame_holder https://en.wikipedia.org/wiki/Flame_holder The ignition at engine start is done with spark plugs. The purpose of the compressor is to provide dense enough air to support combustion, and the pressure is needed to prevent the exhaust gases from blowing out the front of the engine.
- AceyMan 10y ago
  Of tangential relevance: On the aircraft I was trained on, it was SOP to set the igniters = ON when encountering some significant amount of precipitation in flight, as a defense against a water induced snuff-out. (I forget exactly how the precip threshold was determined.) Otherwise, as parent said, the flame persists following engine start, and so the "spark plugs" (igniters) are not kept active.
- mschuster91 10y ago
  > and the pressure is needed to prevent the exhaust gases from blowing out the front of the engine Out of curiosity: has that ever happened and how does such an event look like?
  - 10y ago

dorfsmay 10y ago

This article does a terrible job at explaining how jet engines work. Spending 10 minutes on wikipedia will give you a better idea. Do look for high vs low bypass. Jet engine s are fascinating, the theory behind them is fairly simple, but a huge challenge to make it happen in the physical world, high temperatures as mentioned but also extremely high rotational speed, which requires parts as close to perfection as possible, and very robust, hairline fractures in engines have resulted in plane crashes.

ocfnash 10y ago
Much of the little I know about jet engines was sparked by my reading this wonderful article: https://www.americanscientist.org/issues/pub/each-blade-a-single-crystal https://www.americanscientist.org/issues/pub/each-blade-a-si... (which happily is _not_ paywalled). In particular I learned that each blade is a single crystal! I still find this absolutely mind boggling.
- bigiain 10y ago
  Some people learn in a more hands-on fashion... https://www.flickr.com/photos/bigiain/4081474667/in/photolist-7dECdT-5FyAEF https://www.flickr.com/photos/bigiain/4081474667/in/photolis... (not me, some local guy at a DorkBot meeting way back when...)
azernik 10y ago
I think it does a fairly good job - I read through it in about one minute, and (having already spent some time studying jet engine principles) think it got the essential concepts across. e.g. it doesn't use the word "bypass" but does explain the principle. In such a small amount of space and with the constraints on vocabulary/prior-knowledge assumptions of a mass audience, going into the design tradeoffs of different specific designs is overkill.
- PhantomGremlin 10y ago
  I think it does a fairly good job Yes, I agree. I also loved that they mentioned something I think is really cool --- the gas stream is hotter than the melting point of the turbine blades, and yet the designers have found an ingenious solution.

donpdonp 10y ago

Everything I know about jet engines comes from the fantastic multi-year youtube vlog of AgentJayZ of JetCity, Canada! https://www.youtube.com/user/AgentJayZ https://www.youtube.com/user/AgentJayZ

davidgould 10y ago
AgentJayZ is a great resource and very entertaining.
burntrelish1273 10y ago
Ah... Combustors, combustor liners, vacuum-melted steel, lock-wiring... all the good bits and crazy tolerances explained. Also, reminds me of the Rolls-Royce docu: https://www.youtube.com/watch?v=UazsDDFsS7Q&list=PLFF54B91EB593DF78 https://www.youtube.com/watch?v=UazsDDFsS7Q&list=PLFF54B91EB... Pairs well with some https://youtube.com/arduinoversusevil https://youtube.com/arduinoversusevil, https://youtube.com/Abom79 https://youtube.com/Abom79 and maybe some https://youtube.com/engineerguyvideo https://youtube.com/engineerguyvideo And, if you like aviation: http://www.flywithcaptainjoe.com http://www.flywithcaptainjoe.com

agumonkey 10y ago

digital twin seems like the first start of a humonculus.

Shivetya 10y ago

the detonation engine, would is sound like a hyperactive V1?

DrScump 10y ago

I was hoping that this was about a discovery that jet engines can become quantum-entangled.

M_Grey 10y ago
It's all fun and games until a careless measurement causes one set of engines to be "on" and the other to be "off".
- DrScump 10y ago
  You gotta make sure that both entangled engines don't end up on the same plane.
  - M_Grey 10y ago
    At worst... you'd go in circles. At best you'd just sort of lazily zig-zag to your destination. "Goddamn it Roger, port #2 is in a superposition of existing and not existing again!" "Calm down Wilco, just take a good hard look at her and she'll settle down."

coredog64 10y ago

> They’re so difficult to make, in fact, the companies that build aircraft don’t make their own engines. Airframe manufacturers are prohibited from doing so. The "United" in "United Airlines" harks back to when Boeing, Pratt& Whitney and an airmail company were integrated into a single company. Today, when an airline buys a commercial airliner, the airframe and engine purchases are separate even though the airframe is specific to a single engine type.

M_Grey 10y ago
Could they unite those elements of the industry again if given the chance, or has it moved on to just be too specialized?
- klodolph 10y ago
  I found this discussion on Quora: https://www.quora.com/Why-are-airframes-engines-developed-manufactured-by-separate-companies-especially-on-airliners-How-did-this-symbiotic-relationship-evolve https://www.quora.com/Why-are-airframes-engines-developed-ma... And this Wikipedia article: https://en.wikipedia.org/wiki/Air_Mail_scandal https://en.wikipedia.org/wiki/Air_Mail_scandal It sounds like a combination of antitrust concerns and just the fact that airframes and engines don't have much in common.
  - M_Grey 10y ago
    That was a good read, and I agree with your conclusion.

Merad 10y ago

If you find jet engines interesting, check out AgentJayZ [0] on youtube. He runs a shop in Canada that repairs and overhauls smaller jet engines (think, Learjet size rather than 777 size). He has a mix of good videos, including a long running Q&A series. [0]: https://www.youtube.com/user/AgentJayZ https://www.youtube.com/user/AgentJayZ

davidgould 10y ago

Rolls Royce publish an excellent book "The Jet Engine" with a great deal of information about the design and manufacture of jet engines. I purchased the latest print edition and it's well worth it. However there is an online PDF of an earlier edition at http://airspot.ru/book/file/485/166837_EB161_rolls_royce_the_jet_engine_fifth_edition_gazoturbinnyy_dviga.pdf http://airspot.ru/book/file/485/166837_EB161_rolls_royce_the...

mnw21cam 10y ago
Oh, wow. Grew up with that book in the house (probably the first edition), and yes it is fantastic.