How efficient are Nitinol engines?
The engine efficiency in terms of the energy loss due to friction and the heat-transfer coefficient is analyzed and estimated to be about 16%. It is seen that higher thermal efficiency can be obtained if a Nitinol alloy with a larger H value than given above can be found.
How does a Nitinol engine work?
The Nitinol exerts torque on the lower (smaller) wheel as it tries (in vein) to return to its original shape. This torque spins the lower wheel, and more Nitinol is drawn into the hot water. The other side of the loop is cooled by the air which momentarily relaxes the wire as it passes around the smaller pulley.
What is Nitinol three gives unique properties of Nitinol?
Nitinol is a metal alloy of nickel and titanium with unique properties, including superelasticity or pseudoelasticity and “shape memory” properties. That means nitinol can remember its original shape and return to it when heated. It also shows great elasticity under stress.
What is Nitinol wire?
Nitinol Wire Description Nitinol is a nickel-titanium alloy with super elasticity and shape memory properties. Shape memory refers to the ability of Nitinol to undergo deformation at one temperature, then recover its original, under formed shape upon heating above its transformation temperature.
How efficient is a Stirling engine?
The Application of Stirling Engines for Power Generation In solar thermal applications a Stirling engine could theoretically achieve close to 40% energy conversion efficiency. The best so far recorded is 32% which is still high for solar conversion.
How strong is nitinol?
At room temperature, nitinol has an ultimate tensile strength of between 103 and 1,100 MPa. By way of comparison, steel possesses a tensile strength of between 300 and 2,400 MPa, depending upon the material’s composition.
What is Nitinol mainly used for?
Nitinol tubing is commonly used in catheters, stents, and superelastic needles. In colorectal surgery, the material is used in devices for reconnecting the intestine after removing the pathogens.
Why do we use Nitinol?
Nitinol is used for the wiring and brackets that connect teeth. It’s the perfect choice for braces because the alloy is able to bend and shape itself to the requirements of the patient’s tooth formation. In endodontics, Nitinol is used during root canals, specifically for cleaning and helping to shape the root canal.
What can you use Nitinol for?
How strong is Nitinol?
Why are Stirling engines so inefficient?
Stirling engines by definition cannot achieve total efficiencies typical for internal combustion engine, the main constraint being thermal efficiency. The heat energy source is generated external to the Stirling engine rather than by internal combustion as with the Otto cycle or Diesel cycle engines.
What are the tensile curves of nitinol wire?
But in Nitinol, the Fig. 1 DSC and 37 C tensile curves of the same wire heat-treated three different ways are shown, highlighting that plateaus are not dependent upon Af. The dashed black curves represent a heat treatment that produces properties conventional to the medical device industry.
What should the transition temperature of nitinol be?
The temperature at which the material can no longer recover the elastic strain depends upon the alloy composition and processing and can be adjusted to between = -20·C and =+ IOI,YC. This transition temperature is an important characteristic of nitinol components used in medical applications.
Why is the phase diagram nonlinear in nitinol?
There are aspects of Nitinol’s stress–temperature phase diagram that are simpler than that of water—for example, the liquid-steam transus is nonlinear because the volume of steam is dependent upon temperature. But in Nitinol, the
Which is Superelasticity and shape memory of nitinol?
Superelasticity and shape memory of nitinol. Conventional metalliC materials such as stainless steel, titanium and Eigi lloy a.o., which are used in stents, filters and other interventional devices, exhibit a distinctly different elastic deformation behaviour from that of the structural materials of the human body.