simple stirling hot air engine made at home with simple tools ,2 cans a baloon

[vaughn]

Cite? Remember you are claiming it "powers" them. Where used they
are _auxilliary plants for electrical power_ not propulsion per
google.

While I am not one to defend "News" or the AirCar, but as an ex-submariner I
can't take your point here. My submarine had a heat engine-driven plant that
provided both propulsive and electrical "power". Just to confuse things, even
though the sub was normally propelled by steam turbines, we had two ways to
propel ourselves via electrical "power" from any of three different sources
(Turbo-generators, aux diesel, or battery).

I don't know anything about the European AIP submarines, but non-nuclear
submarines typically are driven only by electrical motors. There is no direct
connection between the shaft and the engine. Therefore, the electrical system
is part of the propulsion system.

Vaughn

 

[Jim Wilkins]

...> I don't know anything about the European AIP submarines, but
non-nuclear submarines typically are driven only by electrical motors.
There is no direct connection between the shaft and the engine.
Therefore, the electrical system is part of the propulsion system.

Vaughn

http://www.kockums.se/en/products-services/submarines/stirling-aip-system/

It appears to be an add-on that is limited by the size of the cryogenic
oxygen supply.

My uneducated wild guess is that the Stirling lets the vessel hide silently
on the bottom much longer, they say weeks versus days. It doesn't look big
enough to substitute for the Diesels for main propulsion.

jsw

 

[vaughn]

My uneducated wild guess is that the Stirling lets the vessel hide silently
on the bottom much longer, they say weeks versus days. It doesn't look big
enough to substitute for the Diesels for main propulsion.

Look at the diagram again. The system charges the main battery, which is used
both for ships systems and propulsion. No doubt, the AIP system doesn't match
the capacity of the main diesels, but still can be used for limited propulsion.

Vaughn

 

[Jim Wilkins]

Look at the diagram again. The system charges the main battery, which is
used both for ships systems and propulsion. No doubt, the AIP system
doesn't match the capacity of the main diesels, but still can be used for
limited propulsion.

Vaughn

Yes I saw that. If the device beside the computer monitor is the Stirling
engine it could extend the range only slightly. Presumably the Stirling is
big enough for the environmental systems, considering that they have the LOX
tank boil-off for breathing oxygen.

jsw

 

[vaughn]

. Presumably...

You get to have your presumptions, I have my own. (-:

Vaughn

 

[Jim Wilkins]

...Presumably the Stirling is big enough for the environmental systems,
considering that they have the LOX tank boil-off for breathing oxygen.
jsw

Here is an overview of those systems:
http://web.mit.edu/12.000/www/m2005/a2/8/pdf1.pdf

jsw

 

[Jim Wilkins]

...> I'm pretty well over my own head with this stuff. I've had some
serious help from this group. I've forgotten who, but someone was
insistent that I needed to get a copy of Steam Tables, ...

I just stumbled onto this warning:
http://en.wikipedia.org/wiki/Pyrophoricity
http://en.wikipedia.org/wiki/Raney_nickel

jsw

 

[Mho]

Ohhh Gawd! More terrorist tips!


----------
"Jim Wilkins" wrote in message I just stumbled onto this warning:
http://en.wikipedia.org/wiki/Pyrophoricity
http://en.wikipedia.org/wiki/Raney_nickel

jsw

 

[Jim Wilkins]

Ohhh Gawd! More terrorist tips!

"Jim Wilkins" wrote in message I just
stumbled onto this warning:
http://en.wikipedia.org/wiki/Pyrophoricity
http://en.wikipedia.org/wiki/Raney_nickel

jsw

Don't tell them about matches.

 

[Han]

I'm still planning to do initial testing with pure nickel, so
(hopefully) pyrophoricity shouldn't enter into the picture just yet.

I'm not an expert, but it seems to me that many "lower grade"* metals might
catch fire if sufficiently finely distributed - just as steel wool can
catch fire, and is sometimes used as firestarter. However, under the
circumstances you might be using the nickel, I'd assume that there is no
oxygen, hence no fire hazard until you open up the containing device,
intentionally or unintentionally.

* "lower grade" here means lower on the scale of metal nobility.

 

[Han]

I have two batches of powder, a half-kilogram jar from a reagent
supply company and a one-pound ZipLoc bag from an eBay vendor. Neither
was particularly well-sealed and I haven't seen any problems. The
safety sheet for powdered nickel warns against inhaling, ingesting, or
absorbing powder through skin/eyes. I'm being careful.

The plan is to load the Ni into the reactor chamber/containment
vessel, then seal and evacuate the chamber to remove the oxygen before
introducing hydrogen. At this stage of the planning process, I'm a lot
more concerned with H2 safety than I am with Ni problems.

The control software design is centered about finding any deviation
from "tame" behavior, and automatically shutting the reactor down if
any such deviation is found. It appears that a full ("cold") automatic
shutdown can be completed within about a tenth of a second - which
should make it much safer than the big fission reactors.

I don't know the properties of your Ni powder, Morris. I was afraid that
you'd have to rigorously exclude oxygen and water, but to my surprise for
reduction reactions with H2 and Raney-nickel that doesn't seem necessary,
based on at least one example here:
<http://orgsynth.org/orgsyn/pdfs/CV3P0229.pdf>

I got to this from:
http://en.wikipedia.org/wiki/Nitrile_reduction, which I got from googling
for "reduction reaction with hydrogen and raney nickel"

 

[vaughn]

automatic shutdown can be completed within about a tenth of a second - which
should make it much safer than the big fission reactors.

It all depends on how you define "shutdown". In the naval reactor I used to
operate, I could have the rods sitting at the bottom in about a second, but the
reactor was subcritical after the first few inches of rod travel. However the
recent debacle in Japan taught us that there can be many definitions and many
levels of "shut down".

Vaughn

 

[Jim Wilkins]

...> Shutdown consists of removing power (if still on) from the
pre-ignition heater, closing the first valve to stop the flow of H2 and to
protect the pressure regulator, ...
Morris Dovey

Can you find a normally-closed valve for that, so the power fail
configuration is safe?

jsw

 

[Jim Wilkins]

...> My present thinking is to use mains power for only the ignition
heater, and battery power for everything else.

The controller battery looks like

http://www.liquidware.com/system/0000/2322/Mega_BackPack_OnTop.jpg

And the rest are just plain old gel cell motorcycle batteries from an
earlier project.
Morris Dovey

Regardless of the power source, when you see smoke or flame or hear hissing
you want to slap the big red KILL button.
http://basicelectricalengineering.com/3_wire_example.html
http://www.amazon.com/Mushroom-3-Prongs-Emergency-Button-Switch/dp/B0050MQ9LC

jsw

 

[Bob F]

The reaction here appears entirely dependent on temperature and gas
pressure in the reaction chamber. I'm inserting a first solenoid valve
in the hydrogen supply line between the regulator and a T-fitting to
kill the gas flow, and a second solenoid valve in the line between the
T-fitting and an evacuated tank. The third leg of the T-fitting
connects to the reactor gas port.

Shutdown consists of removing power (if still on) from the
pre-ignition heater, closing the first valve to stop the flow of H2
and to protect the pressure regulator, and then opening the second
valve to evacuate the reaction chamber. As the chamber is evacuated
the pressure will drop precipitously and that will cause a
corresponding temperature drop. After the first valve has been closed
and the second has been opened, the pressure regulator will be closed.

The fusion reaction should stop long before the pressure drops even to
atmospheric, and the (coincidental) temperature drop should provide a
double measure of safety, although residual heat in the reaction
chamber won't much matter because the necessary H2 component won't be
present.
If this sounds simplistic and crude, it's because it is - but it
should suffice to determine with reasonable safety whether or not a
fusion reaction can be induced at all. If it can, then the next phase
will investigate the effects of post-ignition modulation of the gas
pressure to attain/maintain a given target temperature.

Do you have overpressure sensing?

 

[Bob F]

No, but would be delighted if you have a practical/affordable
suggestion.

Don't know if I can help, but what pressures do you expect. What can the
hardware handle? You don't want a pressure rupture if the pressures are high.

 

[Curbie]

Morris,

I already have a complete project (in C) that measure temperature,
aren’t your pressure directly related to temperature???

The project is intended to become "Open Source", so you’re welcome to
it if you want it.


Arduino Uno adafruit https://www.adafruit.com/products/50
$30.00
LCD disp 20x4 adafruit https://www.adafruit.com/products/198
$17.95
12c/SPI adafruit http://www.adafruit.com/products/292
$10.00
DS18B20 temp sensor Tayda
http://www.taydaelectronics.com/servlet/the-205/DS18B20-datasheet-digital-temperature/Detail
$1.75

Measures Temperatures from -55°C to +125°C (-67°F to +257°F)
? ±0.5°C Accuracy from -10°C to +85°C
? Thermometer Resolution is User Selectable from 9 to 12 Bits

Curbie

 

[Curbie]

Morris,

Not really, since the gas is being consumed in the most literal sense of
the word. I had originally thought I could apply the Ideal Gas Law to
derive pressure from temperature - but that depends on knowing the
number of moles of gas involved, and I don't see any way to pin that down.

Well, for distilling, the project this was design for, temperature and
pressure are directly related and I choose to measure temperature, the
project has LCD, button, output switches, and an command/response OS
that might be of some use for you, but for this project, the command
sequence is NOT important so there's no run queue.

All good stuff - I'm working with an Arduino Mega 2560 and like it
fairly well. The Mega cost a bit more but I opted for higher speed and
more I/O capability just to be on the safe side.

I also considered the Mega but the LCD is the bottleneck for loop
timing and I solved that by breaking up the display outputs with
timers. The loop time is under 1ms.

The headache here is that I want to push the reactor to 250°C right from
the beginning, and have an end goal of 380-400°C operation.

I really do like that $1.75 price tag!

I think you're in the land of multiple thermocouples, they're are not
very accurate, but a way to get more accurate readings, is to read the
thermocouples many times, then average their readings by time slice.

I know I saw pressure sensors, but I don't recall what their ranges
were.

Good luck,

Curbie

 

[Jim Wilkins]

...
I think you're in the land of multiple thermocouples, they're are not
very accurate, but a way to get more accurate readings, is to read the
thermocouples many times, then average their readings by time slice.

I know I saw pressure sensors, but I don't recall what their ranges
were.
Curbie

The hydrogen-rated pressure sensors I found cost $400 each, and had warnings
about long-term hydrogen embrittlement of their sensing disphragms.

I checked three type K thermocouples from different sources in boiling water
and saw less than half a degree error. The stainless clad probe was best by
only a little over the 24 and 20 gauge welded wires.

Pure lead melts at 327.5C. If it's pure it will melt all at once, if not it
will solidify over a temperature range. It's used for black powder cast
bullets. Lead for modern bullets is a lower-melting alloy.
http://en.wikipedia.org/wiki/Solder

The inaccuracy of thermocouples comes from variations in their alloy
composition, and mainly poor contact with the object being measured.
Statistical averaging won't help, it's a systemic error, in my experience
always low. The ones wired to my wood stove rise or fall in steady 0.1C
steps as it heats or cools with almost no noise bounce.

jsw

 

[Curbie]

Hi Jim,

Good stuff as always.

I did tried multiple thermocouples to even out the variations in their
alloy compositions and statistical averaging to average out noise on
the wires, then calibrated with temperature sensors, and was never
able to get the thermal couples to maintain <1C in relation to the
temperature sensors. Probably just me, through I got 2 batches a 3
DS18B20 temperature sensors from 2 two different sources and they read
<.5C between all senses between both batches, just cheapo
thermocouples I guess.

Curbie