BOOK IN SERIES
Fig. 1.7 shows the behavioral similarity of an electric resistor and the resistivity of a hydraulic line.
The figure shows the linear proportionality between the electrical current I and the voltage
difference ∆ V across an electrical resistor. For the same voltage, small resistance passes electrical
current larger than largr resistance. Similarly, the figure shows the linear proportionality between the
fluid flow Q and the differential pressure ∆ p across a hydraulic line. A hydraulic line with large
diameter is less resistive than a hydraulic line with small diameter. So, for same differential pressure,
large diameter line passes flow rate larger than small diameter line.
Fig. 1.7 - Similarity Characteristics of Electrical Resistance and Hydraulic Lines
Equations 1.3 and 1.4 confirm the linear proportionality between the effort variable and the flow
Variable in both elements.
84
∆ .
∆ .
Where:
R is the resistance that depends on the dimensional parameter of the resistive element.
Electrical resistance has the units of Ohm (Ω).
Hydraulic line resistance has the units of [bar / (lit/min)].
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