Air Temp Nitinol

[memoryman]

Nitinol engine are very inefficient<10%). Cost vs output energy is too high for practical use. I have extensive practial experience with Nitinol and Flexinol. The specifications are widely available.

[ramset]

memoryman

this thread Gadgets first reply #1
Quote
This type of Nitinol wire can lift 30 pounds 30 inches with just a 30 degree F shift in tempature differential
end quote

Seems a big movement of a heavy weight at a small temperature differential ?

if accurate

do you have any data
respectfully
Chet K

[memoryman]

"This type of Nitinol wire can lift 30 pounds 30 inches with just a 30 degree F shift in tempature differential "
Seems impossible if done directly; see http://www.tinialloy.com/pdf/introductiontosma.pdf

[sm0ky2]

The real test for Nitinol would be to graph how much force is exerted from a specific thermal change in a nitinol spring.

Something like:
* Acquire a nitinol spring with a known mass (for example, 10g).
* Attach the spring to a fixed weight and place both in a sealed air-tight container.
* Add a heating element, hair dryer, hot-plate, or other type of heater to the chamber, along with a small fan to recirculate air.
* Graph the change in the mass's height with changes of temperature in the chamber.  That temp gradient is dependent on what variety Nitinol you purchased.

After that is all done, take the mass of the spring and temperature gradients to get joules input to the system. (0.20 cal/g * deg. C for Nitinol)
Graph that against the change in height of the test mass (convert ft-lbs to joules).
The result should look like a 'joules input vs joules output' COP chart spanning a temperature range.

If Nitinol is as magic as it sometimes seems, there should be a small window on that graph where Joules output exceed Joules input.

As mentioned in the video from the 70's this was done
The results were something to the tune of 75lbs per sq inch
With some negligible temperature difference.
A friction heater using that force could easily achieve.

[sm0ky2]

Nitinol engine are very inefficient<10%). Cost vs output energy is too high for practical use. I have extensive practial experience with Nitinol and Flexinol. The specifications are widely available.

Not sure what this is based from. Sounds like it could be the toy
Which is just a loop of wire on 2 pulleys.
Many of these are inefficient and just ad-hocked together
The actual engine this was based on used 2 different sized pulleys
And the lower pulley was angled to allow a specific dimension of wire
to be submerged in the warm water. Which gave the motor a higher
efficiency than any Carnot cycle based engine.
In laboratory settings thermal conversion efficiencies of 60-90+%
have been reached. Note that a Carnot engine caps out at 50%


As far as "Flexinol" is concerned, I would steer clear from these guys
They are overpriced and the only real function they serve as a Nitinol
Manufacturer is their ability to fill large bulk orders, such as that required
by large research firms, educational institutions, and NASA.


We have available many low-cost suppliers that can fill our small needs
at a fraction of the cost of "Flexinol". Which is the same alloy, just has a
brand name attached to it.


There are also people that "resell" this stuff. Sometimes for thousands of dollars.
so be careful when purchasing large quantities.


The wire is easy to come by, but the real magic is in plates or strips
The same heat source can provide much more power


There are also many ways to use this stuff, some are better than others
Most of that has to do with the builders engineering skills.
Not the Nitinol itself.
The weighted test gives the most accurate results.
Because we have a direct work function
A Nitinol engine, based on rotary crankshaft, performs tens to hundreds
of times better than an ICE or steam engine, with the same BTU of fuel.
This of course is expanded over longer tests, which is the reason for variance.
But what the tests proved was that the metal itself could replace the
combustion chamber as a piston actuator.
I think this should be a major focus of our tests.
A linear reaction tied to a crankshaft.
I have about 9 days before I get to set my new lab up, but I'll be getting some wire
and as many large pieces as I can afford.
The alloy itself has been standardized to the specs of the most active alloy recipe.
So they are literally the same, regardless of the source.
( 3 forms: memory alloy, superelastic, and the more rare magnetoreactive alloy)


The memory alloy is the one we want for thermal to mechanical conversion


Still thinking through all the ways to achieve linear actuation with the timing of
warm to cold,
My mind made a funny with a tea-light candle on top of a pendulum, so the
flame went back and forth across the Nitinol actuators.
the flywheel stretches the metal back out
the heat "pulls" the crankshaft around.


It's backwards from the ICE, more in line with a vacuum engine, in that it pulls.


Which brings us to the Nitinol Vacuum pump and engine.
The linear actuator operates a piston which draws a vacuum into a chamber.
Through a check valve, resulting in a drop in pressure in the chamber.
This negative (to ambient) pressure can be used in any standard way, or
a small wind turbine jet fan can be placed on the chamber to generate electricity
by stabilizing the vacuum pressure.


Nitinol can also be heated by passing an electric current through the wire.
This incurs a great loss, so it cannot be used for energy generation
However there are infinite applications in robotics, artificial muscles are the new thing.
This, when incorporated with a stabilization of system temperature, (cooling system)
can make a very robust and stable robotics platform, that simulates any form of life.
At least in the muscular sense, (and circulatory when considering the cooling lines)
So far the scientists have stuck to insects and earthworms
But building a humanoid android is not far from reach.


New knowledge and understanding of Nitinol "training" has brought forth
'artificial muscles', that not only can sustain indefinite use, but get stronger
over time, more resilient against factors that reduce 'training'.
This may lead to higher overall efficiency of electro to mechanical conversion
What interesting, is that the circuitry to control a multitude of large muscle groups
made from Nitinol 'muscles', begins to resemble the electrical circuit of a primitive brain.
This can be simplified with IC chips and make it appear less organic on the inside, but
the electrical connections and the way everything is wired up,
It's truly an artificial muscle.
I wouldn't by surprised to see an experiment of Nitinol being actuated by a nerve signal
from one or more of the higher mammals.