Would it Be Possible

Nitinol Heat Engines - Imagesco

Seems plausible.

We had a thread about that not too long ago...

http://cr4.globalspec.com/thread/107830

If any calcs have been done, watch for misplaced decimal points.

I suspect that for whatever size and weight are involved, the power output will be low; maybe useful for novelties or some stationary applications.

Be it a novelty or an energy source where the decimal point comes with lots of zeros, there are 'smart' sensors that use similar combination strategies ... so why not.

Because the thread is about engines rather than sensors.

Engine: a machine with moving parts that converts power into (output) motion
Sensor: a device (or micro machine) which detects or measures a physical property
and records, indicates, or otherwise responds to it (with an output).

There are similarities between engines and sensors ...
often just a matter of size, perspective and practical application.

That's even stretchier than taffy.

That's actually one of the amazing properties of Nitinol - superelasticity!

Vacuumschmelze, a German company makes a variety of these materials called CALORIVAC. Plenty of info is available about change in enthalpy at the temperature . They have many materials with Curie temperature as low as -15°C to as high as 70°C. I was trying to see how I could use the same property to generate power- as material is mechanically oscillates on its own from a hot body to cold ambient. This mechanical oscillator can be used to further generate V= dø/dt from another coil and magnet.

Please give some meaningful numbers, if any.

I have a big hard copy catalog of Vacuumschmelze in my hand. I am sure you can down load data sheets from website.

http://www.vacuumschmelze.com/index.php?id=1146&no_cache=1

http://www.vacuumschmelze.com/fileadmin/Medienbiliothek_2010/Unternehmen/Qualitaet/SD_Sicherheitsdatenblaetter/DM/IB131USA.pdf

http://www.vacuumschmelze.com/fileadmin/Medienbiliothek_2010/Unternehmen/Qualitaet/SD_Sicherheitsdatenblaetter/DM/IB131E.pdf

http://www.vacuumschmelze.com/fileadmin/Medienbiliothek_2010/Unternehmen/Qualitaet/SD_Sicherheitsdatenblaetter/DM/IB131E.pdf

Hard copy catalog gives much more info showing graphs of material properties with respect to temperature. Kindly write to Mr Jason Wee, Marketing in Germany and get more details.

Since this is not strictly a heat engine, you might find a surprisingly high "thermal" efficiency! I suspect you are wanting to recover electrical energy from a magnetic field, and a low power input torque to keep this thing moving through the field?

Could there be such a thing as torque gain?

Here's some interesting info for Nitinol projects:

Nitinol Projects

Where are the heat in, heat out points on this design? Those should exist (or other energy input) for an engine to operate in this regime.

I just reread your post. Do you want a magnetic field to cause a rise in temperature to convert to motion using Nitinol? That kind of sounds like an inefficient process!

When Nitinol changes state it takes an influx of heat, not unlike melting ice, and any work it does requires addition of heat with an efficiency limited by Carnot.

Heat generated by the magnetocaloric effect is a result of the increased energy needed to magnetize the Gadolinium and that energy needs to be supplied by moving a magnet or energizing an electromagnet.

But if you could get it to work, it might make an interesting toy.

Well I was just working on the concept...let's say a swinging pendulum with a spring that would give a slight pull on a wire to sustain the motion....the spring made of nitinol coated with gadolinium or engineered material that gained heat upon entering a magnetic field supplied by permanent magnets >1 tesla...now there is an electrical surge generated as well, although quite small, could be supplemented with a copper coil possibly for some assistance....But the whole idea is to have the heat generated by the permanent magnetic field to effect the gadolinium which would then trigger the nitinol...some environmental temperature control may be necessary...but the guy says that 10°K per tesla fluctuation may be possible, this seems a reasonable amount to trigger the reaction....

http://www.sigmaaldrich.com/technical-documents/articles/material-matters/advanced-materials.html

"Rising interest in both the fundamental science and potential applications of advanced magnetocaloric materials has been sparked by recent discoveries of new compounds exhibiting a magnetocaloric effect much larger (in some cases by a factor of two to three) than those found in previously known compounds, including elemental Gd. The most notable examples that constitute a pool of advanced magnetocaloric materials are FeRh,¹¹ La_0.8Ca_0.2MnO₃,¹²and Gd₅Si₂Ge₂ and the related Gd₅(Si_xGe_4–x) alloys;^13,14 the latter references also coined the phrase “the giant magnetocaloric effect” (GMCE) materials. A few years later, several other families of materials have been shown to also exhibit the giant magnetocaloric effect at temperatures close to ambient. These include Tb₅Si₂Ge₂,¹⁵ MnAs and MnAs_1–xSb_x compounds,¹⁶ La(Fe_1–xSix)₁₃ alloys and their hydrides La(Fe_1–xSix)₁₃H_y,¹⁷ MnFeP_0.45As_0.55 and related MnFeP_xAs_1–x alloys,¹⁸ and Ni_2±xMn_1±xGa ferromagnetic shape memory alloys.^19"

^{The number 19 ref led me to this....}

^{http://materials.mcmaster.ca/faculty/niewczas/PDF%20files/Zhang_Niewczas_Magnetocaloric%20effect%20in%20Ni-Mn-Ga%20films.pdf (Sorry, link no longer available.)}

^{Nickel, manganese and gallium...}

http://www.ncbi.nlm.nih.gov/pubmed/15524753

'.. pendulum with a spring that would give a slight pull on a wire to sustain the motion...'

.

'....sustain the motion...' as in the perpetual sense? Solar Eagle? Where is the energy coming from?

.

I'm having trouble with the word "trigger".

My understanding is that as the temperature of the nitinol rises, a phase change occurs, martensite to austenite, and this takes heat energy. It takes even more heat energy if the nitinol has to do work. It's analogous to the heat of fusion required to melt ice.

https://en.wikipedia.org/wiki/Nickel_titanium

Gadolinium gets hot when it's magnetized just like gas gets hot when compressed. In both cases this requires energy input. If the pendulum is swinging through a magnetic field, then the energy will be removed from the pendulum's motion.

https://en.wikipedia.org/wiki/Magnetic_refrigeration

No I'm not saying it would last indefinitely, but the energy is traded back and forth, from the pendulum, which by default is in the magnetic field, then propelled up and out by the heat generated by the field effect on the molecular structure of the gadolinium, and transferred to the nitinol causing a phase change,,, ideally anyway....which then cooling returns to the default position, and repeats....more like popping corn than a pendulum motion....anyway it would be a curious mechanism.....

4 tesla permanent magnet...

http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-wp-021-wg4-22-KUMADA.pdf

Now that, sir, is a MAGNET! I never dreamed they could do that. Halbach effect really works, doesn't it?

How can you heat your Gadolinium with a 3 mm opening, though?

Maybe the gadolinium can be wound on the nitinol 1mm wire, and shoots through the orifice....these then strung together in a continuous loop...

http://www.slideshare.net/eramanagrawal/magnetic-refrigeration-18849319

What is the conversion of 5 Wh/m2 to gauss...?

If you have written 5 Wh/m2 meaning watt-hour per square meter, I am afraid that is energy density, J/m2, not well related to gauss.

I thought those articles mentioned 5 Tesla fields.

Yes that is from post 28 link where they are stating the field strength of the electromagnet they are using in this apparatus...I can't seem to find any way of converting this to the strength of a permanent magnet field ie gauss....The 5 tesla fields are from the Halbach array link, the strongest field from a permanent magnet array I've found...The apparatus from the link in post 28 seems to work well, I was just looking for some idea of the strength of the magnetic field for comparison to what could be constructed from a permanent magnet array...

That does make sense compared to what we had on it before your post. TY

Ah yes...no wonder....that works out quite well.... by Jove...

https://en.wikipedia.org/wiki/Weber_(unit)

http://www.endmemo.com/sconvert/twb_m2.php

That Halbach fellow really knows how to steer a magnetic field!

A NIB permanent magnet is in the low Tesla range. To put it all into perspective:

List of orders of magnitude for magnetic fields

https://en.wikipedia.org/wiki/Orders_of_magnitude_(magnetic_field)

I'll see your levitating frog, and raise you 1 Frogodile....

As long as we don't end up with flying alligators, I am down with that.

Something in the general thinking maybe?
Product of the week: The Engineer

sounds like one hell of a good idea for an experiment!!! Why didn't I think of it first?