Air jet spinning pdf

Spinning is a manufacturing process for creating polymer fibers. It is a specialized form of extrusion that uses a spinneret to form multiple continuous filaments.

A jet engine is a reaction engine discharging a fast-moving jet that generates thrust by jet propulsion. This broad definition includes airbreathing jet engines ...

14.09.2014  · Considerable growth is expected in the production of man-made cellulose textile fibers, which are commercially produced either via derivatization to form ...

Spinning is a manufacturing process for creating polymer fibers . It is a specialized form of extrusion that uses a spinneret to form multiple continuous filaments. There are many types of spinning: wet, dry, dry jet-wet, melt, gel, and electrospinning. [1]

First, the polymer being spun must be converted into a fluid state. If the polymer is a thermoplastic then it can be simply melted, otherwise it is dissolved in a solvent or chemically treated to form soluble or thermoplastic derivatives. The molten polymer is then forced through the spinneret, then it cools to a rubbery state, and then a solidified state. [1] If a polymer solution is used, then the solvent is removed after being forced through the spinneret.

Wet spinning is the oldest of the five processes. This process is used for polymers that need to be dissolved in a solvent to be spun. The spinneret is submerged in a chemical bath that causes the fiber to precipitate , and then solidify, as it emerges. The process gets its name from this "wet" bath. Acrylic , rayon , aramid , modacrylic , and spandex are produced via this process. [1]

A jet engine is a reaction engine discharging a fast-moving jet that generates thrust by jet propulsion . This broad definition includes airbreathing jet engines ( turbojets , turbofans , ramjets , and pulse jets ) and non-airbreathing jet engines (such as rocket engines ). In general, jet engines are combustion engines.

In common parlance, the term jet engine loosely refers to an internal combustion airbreathing jet engine . These typically feature a rotating air compressor powered by a turbine , with the leftover power providing thrust via a propelling nozzle — this process is known as the Brayton thermodynamic cycle . Jet aircraft use such engines for long-distance travel. Early jet aircraft used turbojet engines which were relatively inefficient for subsonic flight. Modern subsonic jet aircraft usually use more complex high-bypass turbofan engines . These engines offer high speed and greater fuel efficiency than piston and propeller aeroengines over long distances.

The thrust of a typical jetliner engine went from 5,000 lbf (22,000 N) ( de Havilland Ghost turbojet ) in the 1950s to 115,000 lbf (510,000 N) ( General Electric GE90 turbofan) in the 1990s, and their reliability went from 40 in-flight shutdowns per 100,000 engine flight hours to less than one in the late 1990s. This, combined with greatly decreased fuel consumption, permitted routine transatlantic flight by twin-engined airliners by the turn of the century, where before a similar journey would have required multiple fuel stops. [1]

Foto:

Video: