This is a model of a spring loaded accumulator. The accumulator pressure varies proportionally to the spring force:



The spring force varies proportional to the spring compression:



where

p		:	Accumulator pressure
F		:	Spring force
A		:	Piston area
c		:	Spring constant
x		:	Spring compression distance

When the hydraulic pressure is higher than the preload pressure, the fluid starts compressing the spring and stops when the accumulator is full and the pressure pMax has been reached:



where

		:	Fluid volume change
		:	Mass flow rate
		:	Fluid density

Implementation

A laminar restriction models the accumulator opening. The conductance of the restriction is put to zero when system pressure is lower than the preload pressure.

Limitations

The compressibility of the oil inside the accumulator is neglected compared to that of the spring.

Reference

Industrial Hydraulics Manual, 5th ed., Maumee, OH: Eaton Hydraulics Training Services, 2008 p. 470.

medium	Value: Oil() Type: Medium Description: Medium in the component
V0	Value: 0.001 Type: Volume (m³) Description: Maximum fluid volume
p0	Value: 10000000.0 Type: Pressure (Pa) Description: Preload pressure
G	Value: 1e-08 Type: ConductanceOfLaminarResistance (m³/(s⋅Pa)) Description: Conductance of laminar resistance
eventScaling	Value: 1000000.0 Type: Real Description: Parameter used to scale down variables so that events are triggered correctly
pMax	Value: 20000000.0 Type: Pressure (Pa) Description: Pressure when accumulator is full