| CONCEPTS OF FLUID PROCESSES (1) |
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0 | Fluid phenomena have to do with the flow and the storage of fluids… |
1 | In communicating storage elements, levels or pressures of fluids equilibrate (pressure differences become zero as time goes on). Pressure differences are driving forces for fluid processes. If disequilibration is to be created, i.e., if a pressure difference is to be set up, fluids must be forced (pumped). |
2 | Fluids are stored in storage elements, and they can flow. The quantity of fluid in a storage element can be changed by inflows and outflows. This means that we can formulate a law of balance of quantities of fluid. |
3 | Fluids are under pressure. In general, the pressure of a fluid changes from point to point. If we move around a closed circuit in a fluid system, the pressure goes up and down. Finally, we're back at the same pressure. Pressure differences along a closed path add up to zero. |
4 | A fluid in a storage element is under pressure. When we increase the quantity of fluid, the pressure normally rises (there is a relation between quantity and pressure, called capacitive characteristic). How it rises depends upon the fluid and the storage device. |
5 | For a fluid to flow through a horizontal conduit (such as a pipe), the pressure at the inlet must be higher than at the outlet. The pressure of the fluid decreases in the direction of flow because of friction. The pressure drop is related to the flow (the relation is called resistive characteristic or flow characteristic). |
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