Computation of Some Physical Properties of Lubricating Oils at High Pressures I. Density

Abstract

From a survey of available data on the density of fluid lubricants as a function of pressure and temperature, the following empirical equation has been derived: ρ=ρ0(1+ap−bp2)t.ρ is the density at a given pressure (gage) p and temperature t; ρ0 is the corresponding density at atmospheric pressure. The constants a and b are evaluated over a temperature range extending from 20° to 220°F and the density equation is valid over a pressure range of 50,000 lb./in.2. While the equation was derived from data on mineral oils it has been found to hold equally well for animal, vegetable, and fish oils. The variation of density with pressure is independent of the nature of the oil.