Studies in Lubrication V. The Theory of the Thick Film Lubrication of Flooded Journal Bearings and Bearings with Circumferential Grooves

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Abstract
The successive approximation theory for the thick film lubrication of flooded journal bearings and bearings with circumferential grooves is developed through the fourth approximation, that is, including the fifth power of the journal eccentricity. The analysis applies to bearings of arbitrary length, the boundary conditions at the ends of the bearings being satisfied rigorously. It is found that the journal eccentricities and friction coefficients, for fixed Sommerfeld variable, are greater for bearings of finite length than for that of infinite length, the difference increasing with decreasing bearing length. On the other hand the load‐carrying capacities, for fixed eccentricity, of the bearings of finite length are much less than that for the infinitely long bearing. The general theory for the bearing with a central circumferential groove is also developed and it is shown that the only hydrodynamic effect of such a groove is to cut the bearing into two separate end fed bearings, each of half the original bearing length. The load‐carrying and friction properties of these end fed bearings are identical with those of flooded bearings of the same length. The main advantages of such grooving must lie in the maintenance of the lubricant viscosity by the cooling effect of the lubricant flow and in overcoming the negative pressures and possible film rupture that would develop in a flooded bearing without internal lubricant sources.