On Some Experimental Rheological Aspects of Triboparticulates

Heshmat, H. and Brewe, D.E. “On Some Experimental Rheological Aspects of Triboparticulates,” Proceedings of the 18th Leeds-Lyon Symposium on WEAR PARTICLES: From the Cradle to the Grave, Lyon (3-6 September 1991), Elsevier Science Publishers, Tribology Series 18, 1992.

High efficiency engines that operate at high temperatures (400-1500ºF) mandate new innovative lubrication schemes to achieve success.  the most significant technical obstacle is the lubrication and wear at these high temperatures.  Liquid lubricants and conventional bearing designs may not be adequate to meet existing goals.  recent understanding of the nature of third body or particulate solid dynamics suggests an alternative to conventional liquid lubrication and solid (coatings) lubrication system.  It is postulated that a layered shearing of compacted triboparticulates generates velocity, pressure, density, and temperature profiles akin to those in the liquid lubricant in a fluid film bearing.  Thus triboparticulates can be either injected between the making surfaces or generated by wear so as to generate the required flows and pressures to lubricate.  This paper describes a procedure used to select suitable triboparticulates and experiments that are used to develop a fundamental understanding of their behavior.  the results and importance of these experiments to attaining a constitutive equation that can be used to provide design guidelines will be discussed.