Lab Report Vortextube

Theory:

A vortex is a spinning turbulent flow of fluid or gas. The motion of this gas swirling rapidly around a center forms a vortex. One of the best modern day applications of a vortex can be found inside of a vortex tube. The vortex tube is a mechanical device that was discovered in 1928 by George Ranque. The tube is a device that converts a flow of compressed gas into two separate streams. The two streams differ uniquely in that one is hotter and the other stream is colder than ambient room temperature. The feature that makes this device economically sound is the fact that there are no moving parts, but you would still need a source of compressed air or gas.

The high pressure gas enters the tube tangentially at one end and produces a strong vortex flow or “swirl chamber” inside of the tube. The gas separates into the two streams which have different temperatures; one along the outer wall and the other along the axis of the tube.

The speed and rate of rotation of the fluid in a free vortex are greatest at the center, and decrease progressively with distance from the center; whereas the speed of a forced vortex is zero at the center and increases proportional to the distance from the center. Both types of vortices exhibit a pressure minimum at the center, though the pressure minimum in a free vortex is much lower.

A flow with a forced vortex as a central core and a velocity distribution corresponding to that of free vortex outside the core is called a combined vortex and has a circumferential velocity profile.

The state of an amount of gas is determined by its pressure, volume, and temperature. To begin our analysis we will start by evaluating the basic equation known as the ideal gas law. The modern form of the equation is:

P is pressure, V is volume, m is the amount, R is the universal gas constant, and T is the absolute temperature. Applying hot (H), cold (C), and ambient (A) temperature averages this equation becomes more useful as:

References:

http://en.wikipedia.org/wiki/Pressure

http://en.wikipedia.org/wiki/Fluid_flow

http://www.omega.com/prodinfo/pressuregauges.html

http://www.omega.com/prodinfo/pressuretransducers.html

http://www.omega.com/techref/press-trans.html

http://www.exair.com/Cultures/enUS/Primary+Navigation/Products/Vortex+Tubes+and+Spot+Cooling/Vortex+Tubes

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