LUBRICATION MECHANISMS FOR OIL-IN-WATER EMULSIONS

Numerous analyses and experiments regarding emulsions have been conduc ted and seemingly contradictory notions of emulsion behavior claimed. Theoretical approaches include plate-out, dynamic concentration and mi xture theory. Experimental observers, report great disparities in film thicknesses and film thickness dependence on emulsion properties such as base oil characteristics and process variables such as rolling spe ed. This paper surveys the Published research and attempts to reconcil e apparent contradictions from different researchers. Different lubric ation mechanisms of oil-in-water emulsions are identified and describe d all of which are highly dependent on speed effects. At low speeds, p late-out is Sound to be the chief lubricating mechanism. As speed incr eases, the plated oil film is starved leading to a decrease in film th ickness. At even higher speeds, which are typical of most engineering applications, dynamic concentration of oil is the prevalent mechanism. Ultimately, mixture theory becomes useful at very high speeds.