How much power can the F-135 generate

All about the Pratt & Whitney F135 and the (cancelled) General Electric/Rolls-Royce F136
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archangel117

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Unread post29 Jan 2015, 17:21

Hello all,
I've already talked with some colleagues of mine about this but I want to draw from more knowledge and experience that's present here.

Basically I'm reasonably sure that the F-135 can be used for power generation but I'm not sure how much it could generate. The current F-135 engine in the B model puts out 22,000 kw to the fan while the engine puts out 80kn of thrust according to wiki. (apparently this information was mysteriously edited out by a Pieter 1963 sometime yesterday) How much power do you guys think it could make if specifically used for power generation In a combined cycle set up?

I'm asking about this because I'm attempting to make a hypothetical design (if for nothing else just a intensive thought exercise) that requires a extensive amount of power in a small and light weight package. I originally looked at industrial gas turbines but they are all extremely heavy (some even in 1000 tonne range), have low power to weight ratios and are much larger than I would like.
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sferrin

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Unread post29 Jan 2015, 19:51

archangel117 wrote:Hello all,
I've already talked with some colleagues of mine about this but I want to draw from more knowledge and experience that's present here.

Basically I'm reasonably sure that the F-135 can be used for power generation but I'm not sure how much it could generate. The current F-135 engine in the B model puts out 22,000 kw to the fan while the engine puts out 80kn of thrust according to wiki. (apparently this information was mysteriously edited out by a Pieter 1963 sometime yesterday) How much power do you guys think it could make if specifically used for power generation In a combined cycle set up?

I'm asking about this because I'm attempting to make a hypothetical design (if for nothing else just a intensive thought exercise) that requires a extensive amount of power in a small and light weight package. I originally looked at industrial gas turbines but they are all extremely heavy (some even in 1000 tonne range), have low power to weight ratios and are much larger than I would like.



You might want to look at marine gas turbines. IIRC those that power the Ticos and Burkes are based on the CF6 core.
"There I was. . ."
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neurotech

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Unread post29 Jan 2015, 20:39

archangel117 wrote:Hello all,
I've already talked with some colleagues of mine about this but I want to draw from more knowledge and experience that's present here.

Basically I'm reasonably sure that the F-135 can be used for power generation but I'm not sure how much it could generate. The current F-135 engine in the B model puts out 22,000 kw to the fan while the engine puts out 80kn of thrust according to wiki. (apparently this information was mysteriously edited out by a Pieter 1963 sometime yesterday) How much power do you guys think it could make if specifically used for power generation In a combined cycle set up?

I'm asking about this because I'm attempting to make a hypothetical design (if for nothing else just a intensive thought exercise) that requires a extensive amount of power in a small and light weight package. I originally looked at industrial gas turbines but they are all extremely heavy (some even in 1000 tonne range), have low power to weight ratios and are much larger than I would like.

Using the F135 engine core would be an expensive way to generate electricity.

The GE LM6000 engine is designed and somewhat popular for these kind of applications. The CF6 (F138 for military use) is a common engine on 747s, and available surplus pretty cheap. The LM6000 puts out over 40MW at 40% efficiency.

The smaller GE LM1600 is based on the F404 engine used in F/A-18 fighters. The output is ~15MW at 35% efficiency. Industrial turbine setups are usually physically large and heavy due to the cooling requirements, and noise baffling.

If you wanted a lightweight "shaft" engine, whats wrong with a Alison 250 engine from an old Bell helicopter?
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archangel117

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Unread post29 Jan 2015, 23:57

sferrin wrote: You might want to look at marine gas turbines. IIRC those that power the Ticos and Burkes are based on the CF6 core.


Thanks for that I got hung up with various other things and completely forgot about the marine generator sets. Though for this application I would like to supply the generator (along with the power management software) and mounting structure/hardware. The other problem is most are based on a Civilian cores that generally are not rated to handle the shock or G loads this system my receive.


neurotech wrote:Using the F135 engine core would be an expensive way to generate electricity.

The GE LM6000 engine is designed and somewhat popular for these kind of applications. The CF6 (F138 for military use) is a common engine on 747s, and available surplus pretty cheap. The LM6000 puts out over 40MW at 40% efficiency.

The smaller GE LM1600 is based on the F404 engine used in F/A-18 fighters. The output is ~15MW at 35% efficiency. Industrial turbine setups are usually physically large and heavy due to the cooling requirements, and noise baffling.

If you wanted a lightweight "shaft" engine, whats wrong with a Alison 250 engine from an old Bell helicopter?


The cost of developing the F-135 core for this scenario would be acceptable if it would meet all the requirements and have better a P/W ratio than the other options.

The LM6000 would be a good option but it runs into the same issues stated in my reply to Sferrin. The GE LM1600 meets the requirements but I think a F-135 type would have a higher P/W ratio (or so I assume because it does have the highest T/W among amongst fighter jet engines), have better efficency and higher reliability.

As for using the Alison 250 it would take too many to meet the power requirement and also be extremely maintainance entinsive by virtue of having so many moving parts.
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Unread post30 Jan 2015, 01:39

[quote="archangel117..Using the F135 engine core would be an expensive way to generate electricity... The LM6000 puts out over 40MW at 40% efficiency...The cost of developing the F-135 core for this scenario would be acceptable if it would meet all the requirements and have better a P/W ratio than the other options...[/quote]

DDG-51: G.E. LM2500-30;CG-47: G.E. LM2500; FFG-7: LM2500
I'm sure that somewhere there maybe a more rugged gas turbine than the LM2500 but not one with the operating hours.

Also...when would a F-135 become available for your application...ever?
PW is having to provide for the steadily increasing (hopefully!) output for the 3,000+ F-35s.

Maybe a G.E. F-136 with the AETD?? G.E. has intimated, "Through the incorporation of an adaptive fan and third air stream, the ADVENT engine design is capable of providing thermal management superior to that of traditional engines. Adaptive engine technologies enable a 25 percent fuel efficiency improvement and a 30 percent increase in operating range for advanced next-generation, multi-mission aircraft.

This demonstration proves the viability of core technologies key to advancing the adaptive turbine engine concept. The Adaptive Engine Technology Development (AETD) program will build off these and other demonstrations to mature these technologies in preparation for eventual low-risk transition into combat aircraft in the 2020 timeframe. The results of this demonstration, as well as the full engine test, will enable GE to develop a robust, acquisition program-level preliminary design of an adaptive engine, a key deliverable of the AETD program and the foundation for affordable transition of future high performance, fuel-efficient propulsion to combat aircraft."

http://www.wpafb.af.mil/news/story.asp?id=123402957

:)
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Unread post30 Jan 2015, 02:21

The biggest issue is not the amount of power the engine or turbine can generate but how long it can generate. Electricity generators especially those for baseloads are intended to last a long time before servicing is required. Reliability is more important than the level of electricity generated. Fighter engines are intended to generate as much power it can in the air but not for long. Even on an emergency basis, a simple gas-powered turbine already has a MTBO in excess of 20000 hours, far more than a F-135 core will ever have.
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Unread post30 Jan 2015, 03:54

neptune wrote:[quote="archangel117..Using the F135 engine core would be an expensive way to generate electricity... The LM6000 puts out over 40MW at 40% efficiency...The cost of developing the F-135 core for this scenario would be acceptable if it would meet all the requirements and have better a P/W ratio than the other options...


DDG-51: G.E. LM2500-30;CG-47: G.E. LM2500; FFG-7: LM2500
I'm sure that somewhere there maybe a more rugged gas turbine than the LM2500 but not one with the operating hours.

Also...when would a F-135 become available for your application...ever?
PW is having to provide for the steadily increasing (hopefully!) output for the 3,000+ F-35s.

Maybe a G.E. F-136 with the AETD?? G.E. has intimated, "Through the incorporation of an adaptive fan and third air stream, the ADVENT engine design is capable of providing thermal management superior to that of traditional engines. Adaptive engine technologies enable a 25 percent fuel efficiency improvement and a 30 percent increase in operating range for advanced next-generation, multi-mission aircraft.

This demonstration proves the viability of core technologies key to advancing the adaptive turbine engine concept. The Adaptive Engine Technology Development (AETD) program will build off these and other demonstrations to mature these technologies in preparation for eventual low-risk transition into combat aircraft in the 2020 timeframe. The results of this demonstration, as well as the full engine test, will enable GE to develop a robust, acquisition program-level preliminary design of an adaptive engine, a key deliverable of the AETD program and the foundation for affordable transition of future high performance, fuel-efficient propulsion to combat aircraft."

http://www.wpafb.af.mil/news/story.asp?id=123402957

:)[/quote]

While ADVENT engine (awesome name for a program) sounds like it certainly could fit the bill I have no specs or data to go with so I can't really use it. Besides it's not due to be available iirc until 2020's if we're talking that time frame I'd rather choose that fusion reactor lockheed's Skunk works is working on.

In terms of operating hours I don't think the system will be running more than 16 hours continously even in a worse case scenario. ie ww3 all out slug fest.

As for if/when the F-135 would become available I really don't know. Although I don't see too many of these systems being built or needed, probably a absolute max of 6 systems. Though my numbers for the amount of F-135 derived gen sets are shakey at best because I don't know how many it will take to meet the power requirements. Though, I'm hazarding a guess here, It may take up to a maximum of 8 per unit with each unit taking 1+ year(s) to construct.

And yes I know packing that much power into one system is on the verge of ludicrous and perhaps a bit mad, but I like a good challenge.
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Unread post30 Jan 2015, 06:23

archangel117 wrote:...
And yes I know packing that much power into one system is on the verge of ludicrous and perhaps a bit mad, but I like a good challenge.


With that additional info I provide some engineering thoughts. To this example cooling may have just become your biggest issue whatever package you construct.

I'll provide some example thoughts of how challenges shift when we start seeking serious "next BIG step" projects. Russian nuclear icebreakers cannot be sent to Antarctica because the cooling systems can't make the transit through warmer waters. Power wasn't the problem. Even KW per pound of weight wasn't the problem. It was cooling the big reactors.

Another real world engineering challenge emerges when we start trying to create super batteries for electric automobiles. The power per pound of gasoline is pretty impressive. That's why when cars crash they sometimes explode. The great hope for the 100MWH battery in a one ounce, one inch cube has a problem. It would certainly beat gasoline ... but have we considered the "Phenomenal Cosmic Power" - we have squeezed into the "itty bitty living space"? (ie. bomb, talk about molotov cocktails !! )

It sounds to me that your problems will not be how much energy the F-135 can produce ... but how do you plan on managing it?

Just a thought,
BP
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archangel117

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Unread post30 Jan 2015, 06:52

blindpilot wrote:
archangel117 wrote:...
And yes I know packing that much power into one system is on the verge of ludicrous and perhaps a bit mad, but I like a good challenge.


With that additional info I provide some engineering thoughts. To this example cooling may have just become your biggest issue whatever package you construct.

I'll provide some example thoughts of how challenges shift when we start seeking serious "next BIG step" projects. Russian nuclear icebreakers cannot be sent to Antarctica because the cooling systems can't make the transit through warmer waters. Power wasn't the problem. Even KW per pound of weight wasn't the problem. It was cooling the big reactors.

Another real world engineering challenge emerges when we start trying to create super batteries for electric automobiles. The power per pound of gasoline is pretty impressive. That's why when cars crash they sometimes explode. The great hope for the 100MWH battery in a one ounce, one inch cube has a problem. It would certainly beat gasoline ... but have we considered the "Phenomenal Cosmic Power" - we have squeezed into the "itty bitty living space"? (ie. bomb, talk about molotov cocktails !! )

It sounds to me that your problems will not be how much energy the F-135 can produce ... but how do you plan on managing it?

Just a thought,
BP


You're most certainly Right BP cooling will be a feat in its own right. I've got a few Ideas on how to setup the thermal management system(s), some making use of tried and true techniques (using fuel as a coolant then burning it as one example) and a few that I'm not sure will even work. Though thermal management is still something I need to spend a considerable amount more of thought on.
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Unread post30 Jan 2015, 16:39

archangel117 wrote:
blindpilot wrote:
archangel117 wrote:...
And yes I know packing that much power into one system is on the verge of ludicrous and perhaps a bit mad, but I like a good challenge.


With that additional info I provide some engineering thoughts. To this example cooling may have just become your biggest issue whatever package you construct.

... The great hope for the 100MWH battery in a one ounce, one inch cube has a problem. It would certainly beat gasoline ... but have we considered the "Phenomenal Cosmic Power" - we have squeezed into the "itty bitty living space"? (ie. bomb, talk about molotov cocktails !! )

It sounds to me that your problems will not be how much energy the F-135 can produce ... but how do you plan on managing it?

Just a thought,
BP


You're most certainly Right BP cooling will be a feat in its own right. I've got a few Ideas on how to setup the thermal management system(s), some making use of tried and true techniques (using fuel as a coolant then burning it as one example) and a few that I'm not sure will even work. Though thermal management is still something I need to spend a considerable amount more of thought on.


It's not just "cooling" and heat transfer etc. As with the battery example, new paradigms are introduced where simple potentials drive the engineering. The SR-71 for example(X-51 also) simply could not use normal "kerosene" distillate fuel systems. The "operating" environment completely changed the engine design (and structural design requiring JP-7 and expanding joints for materials design). Every fix introduces a new set of problems. See TEB storage/protection for JP-7 engines.

Anway, I'd be surprised if you could simply slap 8 F-135's in a "package" without serious engineering considerations.
Good luck.

BP

PS These are the real issues for Laser and Rail Guns. Any high school kid can make a kazillion MW Laser/railgun. Its the energies that you require/have to manage, that make it a bit more than just that.

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