ANALYSIS OF LUBRICATION AND RHEOLOGICAL CHARACTERISTICS OF MINERAL, PLANT, AND POLYGLYCOL OILS MIXTURES

摘要

In this research, tribological properties of mineral, rapeseed, polyglycol oils and their mixtures were initially studied on a friction pilot stand (tribometer), a replica of a tribological wormgear transmission process. A "Steel ball bearing-three bronze surface" friction pair unit was used. A load of 216N at 0.5 m/s was applied. The coefficients of friction, f, wear diameter scar, d_w, on bronze samples and viscosity index, Ⅵ on more than 50 oil samples in total were analyzed. Using mathematical modeling and simplex-centered optimization methods, optimum concentrations presented in the form of response surfaces on three-factor "composition - property" charts and polynomial equations describing the research parameters were obtained. The procedure includes the design and determination of permissible area and compromise search for viscosity index maximization with subsequent minimization of the other two parameters. Processing of experimental results, checking reproducibility, obtaining mathematical polynomial models describing the surfaces of response, checking the importance of regression factors, truncation of statistically insignificant equation coefficients, checking of the experimental results' representation adequacy of the obtained equations using Fisher criterion were conducted at a 5% significance value.