The cleanliness of lubricating oil in plant equipment is of prime concern since particulate contamination can lead to undesirable wear. It is important to be able to measure the size distribution of such particles in order to control contamination levels. This paper describes our recent experience with turbogenerator oil. The presence of emulsified water and particle agglomeration causes serious complications with the analysis of oil samples. The disturbing effect of these factors can be eliminated by treatment of the sample with isopropyl alcohol and heating respectively.
Two additive free calcium stearate greases have been developed for the requirements of lubrication in automotive components. Two compositions of calcium stearate greases have been prepared by adding 12% and 15% by weight calcium stearate soap in the 450-neutral base oil. Greases have been prepared using the dry technology. The effects of the compositions of calcium stearate soap on the tribological properties of greases have been investigated with the aid of four-ball tester, SRV-Optimol tester, scanning electron microscope (SEM), and transmission electron microscope (TEM). The tribological properties of the additive free greases have been compared with similar application intended commercially available greases containing additives. The structure examinations (before and after weld tests on four ball tester) of the additive free calcium stearate greases have been done using TEM. The FTIR analyses of both synthesized additive free greases have been carried out to study the degradation in greases after weld tests on four-ball tester. It has been observed based on the present investigations that the additive free calcium stearate greases show comparable tribological behavior with commercial greases containing additives.
Combined effects of viscous shear heating and starvation in hydrodynamically lubricated high-speed rolling/sliding line contacts have been investigated numerically by using an efficient computational method for the solution of energy equation in which temperature distribution across the film is approximated by Legendre polynomial. Effects of starvation on minimum film thickness, traction coefficient, and mid-film temperature rise are computed for lightly loaded, lubricated rolling/sliding line contacts. Lubricant starvation in the contact has been created by gradually reducing the length of the computational domain from the inlet side. The performance parameters in the line contact have been evaluated for high-rolling speeds (15 -45 m/s), light loads (10 Â 10 3 -17 Â 10 3 N/m), and slip values varying up to 10 per cent. Significant reduction in minimum film thickness, traction coefficient, and maximum mid-film temperature rise has been observed with the increase in the severity of starvation. The analysis reveals that the existence of starvation seems to be beneficial in terms of reduced traction and temperature rise provided there is a continuous film at the contact. On the basis of this work, empirical relations are developed for the prediction of non-dimensional minimum film thickness, traction coefficient, and non-dimensional maximum mid-film temperature rise in the contact in terms of various operational parameters viz. thermal loading parameter (Q), non-dimensional load (W ), slip (S ), and starvation parameter (jX s j).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.