Rheology and Viscosity Modification

Thin him lubrication is essentially a transition lubrication regime between elastohydrodynamic lubrication and boundary lubrication regimes. Papers devoted to the investigations of this lubrication regime are not enough for engineering needs. In this section, a function to describe the viscosity distribution is proposed in order to attain predictive results and to describe the characteristics of TFL in the viewpoint of engineering. 

The materials used to be employed for making tribo-pairs are metals or metal oxides that belong to a high-energy surface so that it will exert influence on the arrangement of lubricant molecules nearby the solid surfaces. This contributes mainly to the viscosity variety of lubrication oil near to the solid surface. 

As we already know, the viscosity of oil near to the solid wall is limited to a hnite magnitude (whose value approaches the value of the relevant solid). Thus, the variation of viscosity along the direction normal to the wall plane can be described by a function as follows [31] 

according to the experimental result, we roughly choose a = A,b =, 000, and Dg =1.8 nm in a computing case. For these data, the effective viscosity is shown in Fig. 19. 

Considering an example of isothermal, incompressible body in elastic contact with the presumption that there are adequate molecular layers on the minimum film thickness spot, we will get the governing equations as follows 

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