Determination of Gap Surface Temperature Distribution in Axial Piston Machines

The paper presents a new method for determination of gap surface temperature distribution in axial piston machine. A special thermal model has been developed to consider the energy dissipation in the lubricating gap, the heat convection of the fluid and the heat conduction through the rotating group assuming constant case and port temperatures. The energy dissipation in the gap is calculated using gap flow model considering non-isothermal flow, surface deformation and micro motion of parts. The calculated surface temperatures are further used as boundary parameters for the 3D non-isothermal gap flow model. The developed thermal model has been implemented in a new module of the CASPAR simulation software. The program CASPAR has been developed in the research group of the authors (Wieczorek and Ivantysynova 2002, Huang and Ivantysynova 2003). The model will be explained and simulation results will be discussed and compared with measurements. A special single piston test pump has been designed and implemented on a special test rig allowing to measure surface temperature distribution, dynamic pressure field in the gap between piston and cylinder and leakage. The paper will present a comparison of calculated and measured surface temperature fields.