A numerical model of a rock bit bearing seal

The mechanical seal with metal faces, used to seal the bearings in rock dri ll bits, plays a critical role in ensuring a long service life of the drill bit. A numerical model of such a seal has been developed for use as a desi gn tool. The axisymmetric model encompasses a mixed lubrication elastohydro dynamic analysis, and predicts such quantities as leakage rate, film thickn ess distribution, fluid pressure and contact pressure distributions, interf ace temperature and face deformation. Model results show that the behavior of this seal, unlike that of conventional industrial seals, depends strongl y on the ambient pressure, not just on the pressure drop across the seal.