Performance of Starved Journal Bearings with Oil Ring Lubrication

Heshmat, H. and Pinkus, O. “Performance of Starved Journal Bearings with Oil Ring Lubrication,” (1985) Journal of Tribology, Volume 107 (1), pp. 23-31.

There are a number of practical applications when the oil delivered to the bearing represents only a fraction of that required for a full hydrodynamic film.  this occurs when restrictions are placed either on the width of the axial groove or on the supply pressure, as demonstrated in references [1] and [2], or when pump capacity is below that required for full lubrication.  It occurs also routinely when such methods as wick or splash lubrication are used and, as was shown in reference [3], it is an inherent feature of bearings lubricated by means of oil rings.  The latter is perhaps a new element in that, as the tests of reference [3] have shown, not all of the oil scooped up by the ring is delivered to the bearing clearance, but only a fraction of it.

The performance of bearings with partial films will of course be drastically different from those assumed to run with a complete oil film; yet the literature on the performance of starved bearings is scarce.  Of the theoretical papers, aside from the previously mentioned references [1] and [2], Bayada reference [4], offers a fairly good insight into the hydrodynamics of such bearings, including a table of performance for there (L/D) ratios and various degrees of oil starvation.  no experimental data are published to verify the results, either quantitatively or even qualitatively.


The present work reports on an experimental program of testing starved bearings aimed at a two-fold purpose.  one series of tests was conducted with controlled or metered oil delivery, ranging from flooded conditions (full film) to states of extreme oil starvation.  Eccentricity, attitude angle, film extent, and temperatures were recorded.  This should provide performance characteristics of a journal bearing in terms of restricted oil delivery.  the other series of tests was conducted on oil ring bearings in which case, unlike in the first series, the amount of oil delivered to the bearings is not controlled, but is simply a result of the oil ring’s capacity to supply lubricant under a given set of conditions.  here, the degree of starvation is itself an unknown and is dictated by the operating conditions such as journal speed, load and oil viscosity.  The experimentally determined oil delivery is a necessary piece of information before a designer can estimate bearing behavior. 

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