THE BASICS OF POWDER LUBRICATION IN HIGH-TEMPERATURE POWDER-LUBRICATED DAMPERS

The objective of this investigation is to develop a novel powder-lubri cated rotor bearing system damper concept for use in high-temperature, high-speed rotating machinery such as advanced aircraft gas turbine e ngines. The approach discussed herein consists of replacing a conventi onal oil lubrication or frictional damper system with a powder lubrica tion system that uses the process particulates or externally fed powde r lubricant. Unlike previous work in this field, this approach is base d on the postulate of the quasi-hydrodynamic nature of powder lubricat ion. This postulate is deduced from past observation and present verif ication that there are a number of basic features of powder flow in na rrow interfaces that have the characteristic behavior of fluid film lu brication. In addition to corroborating the basic mechanism of powder lubrication, the conceptual and experimental work performed in this pr ogram provides guidelines for selection of the proper geometries, mate rials, and powders suitable for this tribological process. The present investigation describes the fundamentals of quasi-hydrodynamic powder lubrication and defines the rationale underlying the design of the te st facility. The performance and the results of the experimental progr am present conclusions reached regarding design requirements as well a s the formulation of a proper model of quasi-hydrodynamic powder lubri cation.