Units%20Three%20and%20Five

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Units Three and Five Energy Transmission Using
Fluids
Both Liquids and Gases qualify as fluids since
each takes the shape of its container and will
produce flow.
However, gases compress and liquids are
relatively incompressible.
2
Liquids and Gases
Liquid Molecules
Gaseous Molecules
A molecule consists of two or more atoms in
chemical combination.
3
Molecular Energy
Molecular energy is the movement of molecules
within a substance
Molecular energy is affected by temperature.
4
Fluids take the shape of their containers
5
Gases and Heat Energy
6
Gas Temperature, Pressure, Compression, and
Inefficiency
Boyles Law of Gas Compression
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Hydraulic Transmission of Energy
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Pneumatic Transmission of Energy
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Hydraulic Accumulator
10
Positive Displacement Pump
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Positive Displacement Compressor
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Pump Types
1. Gear
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Pump Types
2. Piston
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Pump Types
3. Vane
15
Resistance and Pressure
Any influence that restricts the movement of
fluid is resistance and will effect pressure.
The systematic relationship between resistance
and pressure is directly proportional.
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Heat generation in Fluids
When energy is consumed to overcome resistance,
energy changes form. The energy is transformed
into heat energy.
Examples
Heat from lighting
Heat from machine bearings.
Heat from friction
17
Viscosity
Viscosity is the measure of a liquids resistance
to flow.
As a liquid takes on heat, its viscosity will
change.
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Measuring Viscosity
Viscosity is measured in units called Saybolt
Universal Seconds or SSU.
This is the time it takes for a liquid to flow
through an orifice of a exact size when the fluid
is at a certain temperature.
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Viscosity and Friction generate Heat
A liquid resists movement, this is resistance.
A sharp bend or turn is resistance.
Fluid moving too fast through through a conductor
generates heat because of resistance.
The rate of movement of fluid per foot is
referred to as velocity.
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Viscosity and Friction generate Heat (continued)
Maximum velocities for fluids
Oil 10 to 30 feet per second depending on
pressure. 15 fps is a general rule. Womack,
Vol1, page 37.
Gas 1100 fps, critical velocity.
For oil velocity GPM x .3208/Area
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Pressure Differential
When ever a fluid is moving through a conductor
and there exists a difference between pressure
between any two points, the difference is called
a pressure differential or delta-P.
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General System Design
Avoid sharp turns, obstructions, and anything
that would disturb flow.
Also consider pipe size.