Page 68 - Tribology in Machine Design

Basic principles of tribology 55

Referring to Fig. 2.22

The flow across section X — X is then

and writing x = r®

For continuity of flow, Q must be the same for all sections. Suppose 0' is the
value of 0 at which maximum pressure occurs. At this section dp/d0=0
and the film is in simple shear, so that

Equating these values of Q

Again, taking into account the results obtained earlier, the friction force, q
per unit area at the surface of the journal is

Substituting for dp/d0, this becomes

These expressions for q and dp/d0, together with the conditions of