Pore ensemble statistics in application to lubrication under reciprocatingmotion

The concept of pore ensemble is applied to piston ring lubrication. The sol ution of the two-dimensional Reynolds equation is given for reciprocating m otion of a compression piston ring with circular micropores of rectangular profile on its sliding surface. Minimal film thickness between ring and cyl inder is considered for identical and diverse pore ensembles. It was shown that the pores provide hydrodynamic load support, sufficient to keep the ri ng and cylinder apart even in cases of a linear ring profile and ring surfa ce parallelism to the cylinder wall, through the whole piston stroke includ ing the dead points. Calculations for a 10(3) pore cluster width diverse po re radius and depth teach with not less than 20 percent variance) show that fluctuation of the resulting film thickness is reduced up to 0.5 percent v ariance, while the thickness values of ensembles of diverse pores differ by more than 1.5 times from that found for an identical pore population. Ther e is apparently no need for perfect identity of the pores during production , but pore ensemble statistics must be taken into consideration in proper l ubrication calculations. In general, the pore ensemble is an essential aspe ct in exact determination of the load support and better insight is provide d into the tribological behavior of pore-covered surfaces.