Tuesday, April 24, 2012

Electrical – fluid (hydraulic) analogy

The following table shows some analogy between electrical and fluid systems. It is useful for people who want to understand one of these systems by comparing with another system. Also, it’s pretty useful for hydraulic circuit designers as they may get ideas from existing electronic circuits and apply it to hydraulics.

Electrical
Hydraulic
Electric current intensity (Ampere = Coulomb\sec)
Mass flow rate (kg\sec)
Electric potential difference (voltage difference)
Pressure gradient (difference)
Electric charge quantity
Fluid mass
Flexible wire
Flexible hose
PCB (Printed Circuit Board)
Rigid pipes
Diode
Check valve (one-way valve)
Electric capacitor
Elevated tank or accumulator
Triger diode DIAC
Pressure regulator valve
Battery
Pump
On /off switch
Valve fully-opened/fulley-closed
Electric resistance
Pipe friction, entrance and exit losses, and fittings losses.
Potentiometer (variable resistance)
Proportional valve
Fuse

Step down transformer: Reduces voltage and increases current intensity
Nozzle: Increases velocity and reduces pressure
Step up transformer: Increases voltage and decreases current intensity
Diffuser: Decreases velocity and increases pressure
Inductance: Shows some impedance when electric current changes and has zero impedance when current is fixed
Rotary motor: Shows some impedance when mass flow rate changes (due to rotor inertia).
AC current
Pulsating flow
Dielectric insulator
Seal
Reference Earth (ground)
Reference → Free surface (atmospheric pressure)
Comparator
Differential valve
Logic gate OR
OR (shuttle) valve
Relay
Hydraulic-actuated valve
Optocoupler
Hydraulic coupling
Electric surge
Water hammer
Eddy current
Turbulent flow
KCL
Continuity equation
KVL
Bernoulli equation
Ameter
Flow meter
Voltameter
Pressure gauge
Medium: electric conductor
Medium: fluid
Electric resistivity
Fluid viscosity
Circuit breaker
Isolation valve
Amplifier
Hydraulic intensifier
Bundle cables
Laminar flow element