Inlet Distance Research Articles

An Approximate Equation for Predicting the Isothermal and Nonisothermal Starved Rolling Traction in an E.H.L. Line Contact

In this paper a new inlet distance variable for the starved rolling traction is introduced. By applying a statistical linear regression analysis to the starved E.H.L. question, this new inlet distance parameter enables a seminumerical formula for the prediction of the starved isothermal and nonisothermal rolling traction to be derived. The formula applies for a starved E.H.L. line contact and covers a wide range of the nondimensional materials, thermal loading, speed, load and inlet distance variables. A numerical example using several of the equations developed in this paper has been included in Appendix 1. For the isothermal case, the general formula developed shows good agreement with the two specific semianalytical results reported by Archard and Baglin [11], 1975.

Isothermal Elastohydrodynamic Lubrication of Point Contacts: Part IV—Starvation Results

Utilizing the theory and numerical procedure developed by the authors in an earlier publication the influence of lubricant starvation on minimum film thickness was investigated. This study of lubricant starvation was performed simply by moving the inlet boundary closer to the contact center. From the results it was found that for the range of conditions considered the value of dimensionless inlet distance at the boundary between fully flooded and starved conditions (m*) can be expressed simply as m*=1+3.06Rxb2Hc,F0.58 or m*=1+3.34Rxb2Hmin,F0.56 that is, for a dimensionless inlet distance (m) less than m*, starvation occurs, and for m ≥ m*, a fully flooded condition exists. Furthermore, it has been possible to express the central and minimum film thickness for a starved condition as Hc,S=Hc,Fm−1m*−10.29Hmin,S=Hmin,Fm−1m*−10.25 Contour plots of the pressure and film thickness in and around the contact are shown for the fully flooded and starved lubricant condition. From these contour plots it was observed that the pressure spike becomes suppressed and the film thickness decreases substantially as starvation increases.