Chemical Engineering

> Transport [ 1 / 2 / 3 ]

Apart from the topics so far, let's think about transportation. As I mentioned before, most of the chemical processes produce something by mixing, separation, etc. In that case, obviously things have to be transported through pipes or whatever. Generally speaking, solid is troublesome so it is better to handle as a liquid or vapor - in other words, fluid.

Now then, what is a key of fluid science? The answer is 'friction'. It may sound strange the friction of fluid but of course there is. Think about water dropping from a tap and creeping on a wall. Water on a wall move slowly because of the friction although there would be the other forces, such as surface tension and intermolecular force.

The next question is what affects frictional force or frictional resistance when water moving in a pipe. It is not quite difficult to imagine that the longer the pipe is, the bigger the resistance would be. You may also be able to imgine, the narrower the pipe is, the bigger resistance. If the distance of the pipe become a half, the volume of the water should be a quarter but the surface area between the water and the pipe would be only a half. It means the influence from the surface become double. Another factor is kinetic energy as friction is a phenomenon which turn kinetic energy into heat. Therefore, the more vigorous water lead to the bigger resistance.
( 11th Jan 2005 )
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