**Description**
Hydraulic pumps are widely used on aircrafts for power transmission from engine shaft to actuating systems such as flight control actuator ans landing gear extension/retraction systems. In the scope of this study a pressure compensated axial piston pump is considered which has a 3000 psi nominal outlet pressure which has widely common usage on aircraft applications. Providing correct suction pressure is important for protecting hydraulic pump from wearing issues which can lead to cavitation and extending the working life. Necessary suction pressure is depend on pump rotational speed and provided by pump manufacturers. The general practice for providing necessary pressure is the study of piping design. Deciding reservoir outlet pressure and pipe geometry is a design limit of this general practice. There is also and additional phenomenon which migh become a part of that practice caused by change of pump outlet pressure. On some aircraft applications depressurization valves are employed at startup condition for preventing engine from too much mechanical load. It is observed that by using the Siemens AMESIM simulation tool, Deactivation of this device is caused decrease on suction pressure which is below then the necesary level in some cases. In the scope of this study, an aircraft hydraulic system modelled and correct timing of deactivation of depressurization valve is designated.

**Author(s) - ranked in descending order of contribution / as it should appear when published**
Ayşe Dilek Özkan
Onur Özdemir



Evaluating Aircraft Hydraulic Pump Suction Pressure During Change of Regulating Pressure 

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