Hydraulic Gear Pump Failure Analysis and Tribology Simulation

Surface analysis of hydraulic gear pumps used in gas turbine failure power generation reveals service life limitations due to gear wear and scuffing. A flexible tribology testing capability (WAM) provides an ability to simulate lubrication and failure mechanisms. A load capacity test protocol developed for gas turbine MIL-PRF-23699 oils is found to invoke the same lubrication and failure mechanisms experienced in hydraulic gear pumps. Scuffing, micro-scuffing and traction (friction) data from load capacity tests show variable lubricating qualities among turbine engine oils used in service. A test protocol that monitors the traction coefficient over a range of load stages reflects both wear and scuffing attributes of oils used in service. The test method shows performance differences among oil types within the same specification and a reduction in wear performance with used oils. The test approach provides an opportunity for more efficient development of gear materials, lubricants and engineered surfaces.