High Pressure Rheology of Lubricants (Part 6) -Derivation of Pressure Temperature Linear Equation of Dimensionless Density and Estimation of High Pressure Density - In the extended Dowson-Higginson density equation in the second report, it was found that the reciprocal of the density increase ratio, 1/( pt/ 0t􂈒􂈒1), is proportional to the reciprocal of the pressure temperature, 1/PT. However, it was difficult to understand the physical meaning of the proportional relationship between these two

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... ciprocals. Therefore, in this report, we examined whether a linear equation could be constructed for the relationship between the dimensionless density pt/ 0t and the pressure temperature product PT. As a result, it was found that the dimensionless density 6th power ( pt/ 0t) 6 has a linear relationship with the pressure temperature product PT. We derived the linear equation ( pt/ 0t) 6 PT 1. Considering the physical meaning of the derived equation, the dimensionless density cube ( pt/ 0t) 3 squared ( density substitute function square) corresponds to the pressure temperature product PT. For that reason, it can be understood that the linearization was caused by the dimensionless density 6th power ( pt/ 0t) 6 . This is similar to the linearization of the extended Barus equation in the first report. Since the dimensionless density pt / 0t is unitless and the value itself is one-dimensional, the three-dimensionalization is required to express the characteristics as a substitute function of density. It was consistent with what we assumed to be.