This example shows a typical power unit consisting of a fixed-displacement pump driven by an angular velocity source, a pressure-relief valve, a pressure-reducing valve, and two variable orifices.
The variable orifices simulate fluid consumption in the main system and in the reduced pressure branch. The simulation starts with the variable orifice open, which results in a low output pressure and the maximum flow rate going to the system. The orifice starts closing at 0.5 s and is closed completely at 3 s.
The output pressure builds up until it reaches 75e5 Pa, and is maintained at this level by the pressure-relief valve. At 3 s, the valve starts opening, thus returning the system to its initial state. The pressure reducing valve is set to 20e5 Pa and maintains this pressure downstream, as long as the pressure upstream the valve is higher than its setting.