Fluid Energy

A pessimist is one who makes difficulties of his opportunities and an optimist is one who makes opportunities of his difficulties. 

Energy relationships within fluids are composed of both potential and kinetic energy terms (Section 2.4). The potential energy of a fluid is related to the height of a fluid relative to some datum, and also to the pressure exerted either by or on the fluid. As examples of these, consider the height of sap within the tallest Sequoia tree. In order to raise the sap to this height above the roots, work must be done to the fluid. The taller the tree, the more work that must be done. The potential energy of the sap at the top of the tree would be available to perform mechanical work if it could be harnessed. 

Fluid pressure is likewise able to be used. Pressure can move the fluid through a conduit or can distort the walls of a container. 

FIGURE 2.9.4 The cross-section of an airplane wing shows that the upper surface is longer than the hottom surface. Flow splits at the front and some goes over and some under the wing. Velocity is higher at the top, so pressure is lower. 

FIGURE 2.9.5 The relative pressure increase compared to static fluid pressure is plotted for the surface of a fish. The top curve is dorsal (top) pressure, and the bottom curve is lateral (side) pressure. Pressures are highest in the front and lowest near the outlet of the gills. (From Vogel, S., Am. ScL, 76, 28, 1988. With permission.) 

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Fluid dynamics Fluid energy mills Fluidization... 

The floated mica concentrate is dewatered. After dewatering (qv), the mica is either dried in a fluid-bed rotary drier, flash dried in a fluid energy mill, or sold "drip-dry" to other mica grinders. The dry mica is then ground and screened to a si2e gradation dictated by the customer. 

The general pieces of equipment used in grinding flake mica or mica concentrate into saleable mica products are hammer mills of various types, fluid energy mills, Chaser or Muller mills for wet grinding, and Raymond or WiUiams high side roUer mills. Another method is being developed, called a Duncan mill (f. M. Huber, Inc.), that is similar in many respects to an attrition mill. AH of these mills are used in conjunction with sieves, and all but some types of hammer mills incorporate air classifiers as a part of the circuit. 

High Speed Fluid Energy Mills. This type of equipment is used primarily for preparation of relatively low viscosity mill bases for inks and paints. The first is an impeller type which achieves dispersion by the appHcation of shear. The second type is in the form of a rotor—stator, and the dispersion is achieved by impingement or impact. 

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