Thermoelectric and Magneto-Caloric Effect to Cool the Exhaust in the new B-21 Stealth Bomber!

Thermoelectric and Magneto-Caloric Effect to
Cool the Exhaust in the new B-21 Stealth Bomber!

An interesting highlight I received from another one of my
aerospace "sources" within the last few days indicates that
the Northrup-Grumman-built B-21 bomber may be using the
Peltier–Seebeck effect along the engine exhaust ducting of
the serpentine engines of the new bomber to cool it's exhaust
to levels that raise the stealthiness of that craft to unheard-of
levels in the Infra-Red range.

An interesting side-effect of the cooler engine exhaust is a
lower sub-sonic cruise speed BUT a very large increase in range.
This MAY explain the reduced size and lower ordinance carrying
capability of the B-21 versus the B-2 bomber.

Evidently, the serpentine exhaust exit ducting of the B-21
is surrounded by conductive plates which are charge-wise
polarized. It has been suggested to me that the engine
exhaust itself is charged via other means to form the
second conductor and that the outer plates surrounding
the ducting is the first conductor and the double-walls
of the exhaust ducting form the channel which allows
large-scale and FAST thermoelectric cooling effect
to take place. It has been ALSO suggested to me that
fins or vanes that stick INWARDS into the exhaust flow
are used not only as an aerodynamic exhaust flow stabilization
system but ACT AS the mechanism for creating a large surface
area to further suck the heat out of the engine exhaust.

These vanes are designed much like the curved impellers
seen in ROTAX style engines which have the side effect
of slowing down the exhaust to allow MORE TIME for the
Thermoelectric effect to suck heat away from the exhaust
before final exit.

This cooler air has less propulsive power BUT the engine
control software has been improved to such a point that
better range is the final result and a much lower IR signature.

---

It has ALSO been suggested to me that there might be
a block upgrade to the B2 bomber within 5 years to change
the exhaust ducting of the B2 engines to the same type of
internally vaned thermo-electric cooling technology to
reduce its thermal signature even more than it already is.

Thermoelectric effect
en.wikipedia.org...

Peltier Effect:

See Link
www.marlow.com...

=====

A second more secretive accompanying aircraft to
the B-21 (i.e. not yet disclosed publicly) is rumored
to use an EVEN MORE EXOTIC cooling system to reduce
overall engine running temperature AND cool the exhaust
to allow it to perform its role as a DEEP RECON/ECM
penetrator aircraft in support of the bombing/attack
mission of the B-21. (i.e. possibly codenamed Minotaur?)

Using the fuel burn cycle itself to provide a large
magnetic field which then heats up the walls of its
own composite serpentine engine combustion chambers
and exit ducting, the magnetic field causes the hot
fuel/air mixture AND the engine exhaust to rapidly
lose thermal energy to the engine duct walls which
cool at a rapid rate to outer plate-based ceramic
heat sinks which can absorb enough thermal energy
for a long enough period that multiple mission times
from 12 to 24 hours can be facilitated.

That 12-to-24 hours time limit which has been suggested
to me indicates VERY LONG RANGE missions starting from
INSIDE THE US MAINLAND but extending out as far
at 13,000 MILES !!!! (i.e. 20,000 KM).

I have been told this secondary RECON/ECM aircraft was
designed for very long-range with no refueling and that
a slower and cooler engine run-time via magnetic
refrigeration facilitates the range AND
increases thermal stealth.

See Link for Magnetocaloric Effect:
en.wikipedia.org...

The below is a Japanese Patent for a household/commercial refrigeration
unit which uses the magnetic coloric effect used to illustrate how
the magnetic refrigeration effect works to ATS readers:
www.patentsencyclopedia.com...

And ONE VERY INTERESTING presentation I found:

A. Giri, B. Paterson, M. McLeod, L. Zhou, C. Dennis, B. Majumdar, Y.H. Sohn, K. Cho, R. Shull, “Enhanced
Magnetocaloric Effect in Ni2MnGa Based Magnetocaloric Alloys,” 2013 Energy, Materials and
Nanotechnology (EMN) Meeting – General Workshop, December 7-10, 2013, Orlando, Florida, USA.

with some traces found of funding by GE (General Electric) and it's TurboFan division!

This above patent indicates using certain Nickel/Molybdenum/Gallium alloys in
various electronic circuit and LARGER INDUSTRIAL components to facilitate
magneto-caloric cooling. This paper posits to use such technology to cool
space-rated electronics and AEROSPACE-rated components such as engines!!!!

Cooling of an aircraft engine's electronic components via thermo-electric effects
which indicate INTERNAL ENGINE COMPONENTS COOLING applications are being
worked on which supports the likelihood of other cooling research:

METHOD FOR COOLING ELECTRONIC COMPONENTS IN AN AIRCRAFT TURBOJET ENGINE
Feb 8, 2013 - SNECMA

A method for cooling electronic components present in an aircraft
turbojet engine, the method including disposing a first sensor in
a first zone of the turbojet engine; disposing a second sensor in
a second zone of the turbojet engine, the first zone and the second
zone having a temperature gradient between them; generating, from
the first sensor and the second sensor, electricity by the
Seebeck effect; bringing about cooling of the electronic
components by the Peltier effect, using the electricity
generated by the Seebeck effect.

Publication number: 20130319016
Type: Application
Filed: Feb 8, 2013
Publication Date: Dec 5, 2013
Applicant: SNECMA (Paris)
Inventors: Eddy Fontanel (Paris), Morgan Balland (Moissy-Cramayel), Lucie Mathilde Dawson (Moissy-Cramayel)
Application Number: 13/762,680

====

Other papers and presentation by aerospace companies
such as GE, BAE, Pratt & Whitney, Rolls Royce and even
Northrup have been found containing INTENTIONS TO PATENT
but the PATENT APPLICATIONS coming out of those papers
seem to be SUDDENLY MISSING. Ergo, something suddenly
went "Black Budget" on BOTH the Magneto-Caloric effect
engine cooling AND Peltier-Seeback effect cooling research.

I call THAT a smoking gun......

---

Interestingly, I see NOTHING from Boeing or LMCO about
such fancy engine and component cooling technology!

Very cool! See what I did there?

originally posted by: SonofaSkunk
Very cool! See what I did there?

---

Like I said earlier, The Skunkies have NOTHING in this area that I could see....
And my sources are even DEEPER within LMCO than my
Northrup/BAE/Raytheon/L3/Teledyne/Bell/Daimler/Euro, etc sources....

So if you have something to share about LMCO and Boeing, I'm all ears!

ESPECIALLY if your dad worked on the LMCO USAF spacestation,
SSTO spaceplane, SCRAMJET/pumpkin seed, Cavity Resonator Jetting system, etc......

Seems odd. I have done a lot of R&D with Peltier coolers. We had a hot compenent that needed cooled. We put the cool side of the Peltier cooler on the hot part and the warm side got cooled by fans. The problem I see is the hot part of the cooler was always warmer than the part we were cooling. I don't see how this would lower IR detection...

Possibly the heat is radiated/dissipated over a larger surface area. Interesting post.

originally posted by: Orionx2
Seems odd. I have done a lot of R&D with Peltier coolers. We had a hot compenent that needed cooled. We put the cool side of the Peltier cooler on the hot part and the warm side got cooled by fans. The problem I see is the hot part of the cooler was always warmer than the part we were cooling. I don't see how this would lower IR detection...

Possibly the heat is radiated/dissipated over a larger surface area. Interesting post.

---

With Peltier effects cooling you need a final heat sink
that absorbs all the sucked-out thermal energy.

I would look at a Stirling Engine (i.e. Cryo-Cooler)
as a good start as to how this system MIGHT work
on a practical sense.

See Link:
en.wikipedia.org...

if you look at modern computer with high-performance graphics cards,
SOME of them use Peltier effect cooling which is why the heat sink
is so H-U-G-E because that heat from the GPU/RAM has to be moved
QUICKLY to the opposite end of the cooling circuit and then RADIATED
into another heat-absorbsing material or output via convection using
a fan mechanism.

In this case, I has been described to me that an INTERNALLY-HOUSED
ceramic casing or plating (i.e. very much like the Space Shuttle's
thermal tiles) absorbs the heat from the exhaust for the duration
of the mission (i.e. with no external IR trackable radiative process).
I think the Magneto-caloric and Peltier cooling are the two
ENERGY-EFFICIENT variants for a general mechanical cooling
system but it seems the MISSION-DURATION HEAT STORAGE
system is the KEY part. i.e. a ceramic-plate-or-block-based
thermal energy absorption system. This corresponds well
to OTHER tips and leaks I have received from OTHER sources
within my Aerospace friends network about using active cooling
to reduce thermal/Infrared signature from engine exhaust.

I suggest to you that the thermal absorbing ceramic plates or blocks
ONLY have to work for the duration of the longest specified mission
and after that a "Heat Flush/Heat Dump" can take place back at the
original base of operations. On a math-wise basis you only need a
few cubic metres of ceramic block or tile to absorb enough heat
from a hot sub-sonic engine for it to work over 12 to 24 hours.
That still leaves enough room on the interior of the craft for
a good-sized amount of ordinance, electronics and crew.

Lower than subsonic , invisible but a century to go on the theater great idea , the ennemy will be going before you arrive, soon the same speed of a B-24 liberator .

originally posted by: Orionx2
Possibly the heat is radiated/dissipated over a larger surface area. Interesting post.

Why not use the fuel as a heatsink like the SR-71?

originally posted by: darksidius
Lower than subsonic , invisible but a century to go on the theater great idea , the ennemy will be going before you arrive, soon the same speed of a B-24 liberator .

---

About the same speed as a Boeing 747 at about 570 MPH (920 KMH)
which indicates to me probably is NEARLY the same engine as the
Pratt & Whitney F135 except with the external thermoelectric
plated exhaust ducting probably installed after main production
by it's commercial partner GE (General Electric) who has more
experience in high-bypass cool-running jet engines.

When I hear a range of 13,000 MILES that DEFINITELY indicates
a low temperature, high-efficiency and very cool running jet engine!

Looks like they want REALLY LONG RANGE and SUPER-STEALTH over
speed and ordinance capacity on the B-21 and its companion craft!
It also means almost 99.9997% chance that it will be Arizona, Texas
New Mexico and/or Ohio based for security reasons. I see NO
overseas basing or carrier-based operations at all in this type
of aicraft build scenario!

It will be interesting to see within the next few years a
COMMERCIAL variant used on the Boeing 787 or new B737 or
even Canadair C-series jets used for 100-to-200 passenger
ultra long-range operations at a much reduced flight cost!

a reply to: StargateSG7

The team... added a small amount of graphene to strontium titanium oxide. The resulting composite was able to convert heat that would otherwise be wasted into an electric current over a broad temperature range, beginning at room temperature. Previously, thermoelectric materials only functioned at extremely high temperatures around 700 degrees Celsius.

Gas2.org, Aug. 2015 - Graphene Converts Heat Into Electricity.

Why not convert "waste" heat to electricity? The material is not bulky. It has been known for a while. Even if you store it in batteries there is less heat to deal with.

Just a thought. Nice topic!

S+F

a reply to: StargateSG7
I stay on my opinion , it's a mistake to go slow , now with the mobile launcher you need speed to go on the theater, if your bomber take hours after hours after hours to come the objectif have move since a lot , do you think the ennemy will stay at the same place ten hours after firing ? Don't you think the bomber need dash to escape the futur 5th gen ennemy squadron ?

originally posted by: TEOTWAWKIAIFF
a reply to: StargateSG7

The team... added a small amount of graphene to strontium titanium oxide. The resulting composite was able to convert heat that would otherwise be wasted into an electric current over a broad temperature range, beginning at room temperature. Previously, thermoelectric materials only functioned at extremely high temperatures around 700 degrees Celsius.

Gas2.org, Aug. 2015 - Graphene Converts Heat Into Electricity.

Why not convert "waste" heat to electricity? The material is not bulky. It has been known for a while. Even if you store it in batteries there is less heat to deal with.

Just a thought. Nice topic!

S+F

This is great for COMMERCIAL jet operations but for a military
program like the B-21 this has PROBABLY been in the works for
over a decade now (probably a 2005 pogram start date!) and
the design is probably set in stone for probably AT LEAST
the last five years so it will have to wait for the all-electric
linear induction-powered supercruise-capable B-22 bomber
in the year 2035...... ;-) :-)

originally posted by: darksidius
a reply to: StargateSG7
I stay on my opinion , it's a mistake to go slow , now with the mobile launcher you need speed to go on the theater, if your bomber take hours after hours after hours to come the objectif have move since a lot , do you think the ennemy will stay at the same place ten hours after firing ? Don't you think the bomber need dash to escape the futur 5th gen ennemy squadron ?

The B-21 isn't designed for that type of battle,
whereas the HyperSoar-based or Falcon SCRAMJET-based
systems which can hit anywhere on Earth in less than
90 minutes WOULD work.

The B-21 is probably mostly designed for long-range
Afghanistan/Iraq/North Korea TACTICAL operations
used for destabilizing a political entity and to disrupt
communications and transportation infrastructure.
It would NOT be used for China/Russia Strategic
bombing except in the most dire of situations
such as defending Taiwan against a Chinese invasion.

WE WILL be seeing the B-21 used in Syria, Yemen,
Afghanistan, Iraq in "Police" operations designed
to kill terrorists in their desert camps and
underground bunkers.

We MIGHT see it make some flythroughs to and from
Guam and Japan to show China that the USA means
business in defending other nations against expansion
of Chinese territory within the South China Sea region.

a reply to: StargateSG7

And I can ALSO TELL YOU that the original 100 craft order
by the USAF ABSOLUTELY WILL BE CUT DOWN to less
than 50 by Congress and will go for around $675 Million
each after all is said and done instead of the original
$550 million each. The USAF internally has PLANNED
for that eventually...they asked for 100 and prepared
to get only 50 which I THINK is the original plan anyways!

The secret Minotaur(?) companion ECM/RECON penetrator
craft is PROBABLY what they REALLY wanted funded and
the B-21 is just a bonus aircraft. I suspect that the Minotaur
aircraft PROBABLY was also secretly designed to carry a SMALL
NUMBER of nuclear weapons (i.e. in cruise missiles) as a
secret-need-to-have option.

The TRUE strategic level bomber will be the hypersonic
Falcon (X-41) Common Aero Vehicle (CAV) craft which
can carry conventional and nuclear weapons ANYWHERE
in the world and they will be a LOT CHEAPER to build
and operate than the B-21 !!!!

originally posted by: SonofaSkunk
Very cool! See what I did there?

----

Hot and Stinky! Like a Hog Named Vader.... ;-) :-)

a reply to: StargateSG7

Actually...make that VERY Cool Magneto-Refrigerator
a LOT less hot and loud as a Texas Hog named Vader.... ;-) :-)

originally posted by: StargateSG7

originally posted by: Orionx2
Seems odd. I have done a lot of R&D with Peltier coolers. We had a hot compenent that needed cooled. We put the cool side of the Peltier cooler on the hot part and the warm side got cooled by fans. The problem I see is the hot part of the cooler was always warmer than the part we were cooling. I don't see how this would lower IR detection...

Possibly the heat is radiated/dissipated over a larger surface area. Interesting post.

---

With Peltier effects cooling you need a final heat sink
that absorbs all the sucked-out thermal energy.

I would look at a Stirling Engine (i.e. Cryo-Cooler)
as a good start as to how this system MIGHT work
on a practical sense.

See Link:
en.wikipedia.org...

if you look at modern computer with high-performance graphics cards,
SOME of them use Peltier effect cooling which is why the heat sink
is so H-U-G-E because that heat from the GPU/RAM has to be moved
QUICKLY to the opposite end of the cooling circuit and then RADIATED
into another heat-absorbsing material or output via convection using
a fan mechanism.

I suggest to you that the thermal absorbing ceramic plates or blocks
ONLY have to work for the duration of the longest specified mission
and after that a "Heat Flush/Heat Dump" can take place back at the
original base of operations.

The problem is absorbing it keeps the heat in the plane, in order for IR not to detect it it needs to be dissipated/ Removed from the plane. Taking the heat from the exhaust and moving it to another part of the plane is pointless as the IR will detect it wherever it is on the plane.

What could work though is using the plane itself as the heat sink and using the airflow to dissipate the heat. The larger the surface area the heat transfer to that has airflow the more heat can be removed and the smaller the heat signature.

Pretty impressive technology if it actually exists.

originally posted by: Orionx2

originally posted by: StargateSG7

originally posted by: Orionx2
Seems odd. I have done a lot of R&D with Peltier coolers. We had a hot compenent that needed cooled. We put the cool side of the Peltier cooler on the hot part and the warm side got cooled by fans. The problem I see is the hot part of the cooler was always warmer than the part we were cooling. I don't see how this would lower IR detection...

Possibly the heat is radiated/dissipated over a larger surface area. Interesting post.

---

With Peltier effects cooling you need a final heat sink
that absorbs all the sucked-out thermal energy.

I would look at a Stirling Engine (i.e. Cryo-Cooler)
as a good start as to how this system MIGHT work
on a practical sense.

See Link:
en.wikipedia.org...

if you look at modern computer with high-performance graphics cards,
SOME of them use Peltier effect cooling which is why the heat sink
is so H-U-G-E because that heat from the GPU/RAM has to be moved
QUICKLY to the opposite end of the cooling circuit and then RADIATED
into another heat-absorbsing material or output via convection using
a fan mechanism.

I suggest to you that the thermal absorbing ceramic plates or blocks
ONLY have to work for the duration of the longest specified mission
and after that a "Heat Flush/Heat Dump" can take place back at the
original base of operations.

The problem is absorbing it keeps the heat in the plane, in order for IR not to detect it it needs to be dissipated/ Removed from the plane. Taking the heat from the exhaust and moving it to another part of the plane is pointless as the IR will detect it wherever it is on the plane.

What could work though is using the plane itself as the heat sink and using the airflow to dissipate the heat. The larger the surface area the heat transfer to that has airflow the more heat can be removed and the smaller the heat signature.

Pretty impressive technology if it actually exists.

====

The ceramic plate or ceramic block compounds that were ilustrated
to me seem to have a LOW radiative index but a HIGH thermal absorption
index which indicates to me that they are multi-layered composites.

This allows them to absorb an enormous amount of thermal energy
but KEEP that energy to within the interior confines of the ceramic.

I have personally seen such types of blocks used in aluminum smelting
where a ceramic block was inserted into molten aluminum, superheated
and then taken out and then HANDLED WITHOUT GLOVES by an operator!

I think the composite tiles used in the space shuttle
ARE ALSO of just such a type of material which rapidly
absorbs heat and keeps it within the interior but the
surface is merely warm to the touch.

See link:
en.wikipedia.org...

I suspect any such heat sink system on a B-21 aircraft would do the same.
The heat would be kept to the INTERIOR of the block and NO IR signature
would escape the outer hull for the duration of the mission. There would
be a MAXIMUM POSSIBLE thermal absorption limit specified by the heat
sink size and said material's lack of surface thermal radiative efficiency but
with modern thermodynamic simulation software (i.e. Mathematica) you
could model a specific size and placement of thermal tiles or blocks to absorb
X-number of watts for Y-period of time with Z-amount of external radiation.
Ergo, IR signature would be reduced to a negligible amount.

a reply to: StargateSG7

A good analog is this article where it was found that
the TOMATO SAUCE and the Cheese on pizza absorbed
the MOST heat and kept it within the interior yet the
outer skin of teh tomtoes and the cheese was relatively cool

Article #1:
The Thermodynamics of Pizza (lots of math)
wiki.chemprime.chemeddl.org...

Article #2: PDF of Powerpoint Presentation
www.arm.gov...

So if a block of cheese and a tomato can absorb a LOT of thermal energy
and KEEP IT to the interior for a given amount of time, IMAGINE what
an ENGINEERED ceramic composite could do especially when it's
thermodyanmics have been modelled to an extreme level?

originally posted by: StargateSG7

originally posted by: SonofaSkunk
Very cool! See what I did there?

---

Like I said earlier, The Skunkies have NOTHING in this area that I could see....
And my sources are even DEEPER within LMCO than my
Northrup/BAE/Raytheon/L3/Teledyne/Bell/Daimler/Euro, etc sources....

So if you have something to share about LMCO and Boeing, I'm all ears!

ESPECIALLY if your dad worked on the LMCO USAF spacestation,
SSTO spaceplane, SCRAMJET/pumpkin seed, Cavity Resonator Jetting system, etc......

I got nuthin. Dad lived to be 81 years old and took anything and everything he knew to his grave. The biggest reaction I ever got from him was when I showed him a magazine cover with a pic of the F-117. He took it from me, looked and it and handing it back said with a wry smile, "Nice airplane."

originally posted by: darksidius
a reply to: StargateSG7
I stay on my opinion , it's a mistake to go slow , now with the mobile launcher you need speed to go on the theater, if your bomber take hours after hours after hours to come the objectif have move since a lot , do you think the ennemy will stay at the same place ten hours after firing ? Don't you think the bomber need dash to escape the futur 5th gen ennemy squadron ?

If they are travelling at 80,000 feet and invisible high speed wont be a help..