Research on fluid-structure interaction for piston/cylinder tribopair of seawater hydraulic axial piston pump in deep-sea environment

Seawater hydraulic axial piston pump (SHAPP) is a critical power component in underwater operating systems. A parameterized elasto-hydrodynamic (EHD) lubrication model of the piston/cylinder tribopair in the SHAPP is originally established, which considers the elasto-hydrodynamic behavior, viscosity temperature effect and deep-sea environmental pressure The deformation of piston bush, bearing mechanism and energy loss characteristics of the water film under different operating conditions are discussed The results show that the deformation of piston bush made of polyetheretherketone (PEEK) is in micron-scale under water film and deep-sea pressure, which could increase the leakage and viscous friction power loss of piston/cylinder tribopair. In deep-sea environment, the leakage and viscous friction power loss calculated by EHD are always greater than those calculated by hydrodynamic (HD), and increase with the increase of working pressure, shaft speed, gap size, sea depth and piston bush thickness Resides, the increase of sea surface temperature could increase the leakage and decrease the viscous friction power loss of the piston/cylinder tribopair, respectively. Finally, design instructions to optimize the piston/cylinder tribopair are presented, therefore the proposed methodology can be used as a designing tool for SHAPP.