Lubrication performance analysis of Lead-Bismuth Internal-Feedback bearings in the nuclear main pump system

Abstract

The significant equipment of the rotor system and circulating pump are lubricated bearings. Lead-bismuth pumps use high-temperature liquid lead–bismuth as the lubricant in its internal feedback dynamic and hydrostatic bearings. Through the numerical simulations, the lubrication capabilities of a lead–bismuth bearing are examined in this work. The pressure distribution, load-carrying capacity, minimum film thickness and power loss of a lead–bismuth bearing with various radial gaps are evaluated in relation to three parameters: rotational speed, eccentricity, and differential pressure. The findings demonstrate that the lead–bismuth internal-feedback hybrid bearing's bearing capacity is mostly dependent on static pressure, with some support from dynamic pressure. The dynamic pressure effect is related to the eccentricity, rotating speed and radius gap of lead–bismuth bearings. Throttling is accomplished via the feedback groove. Lead-bismuth bearings with various radius gaps exhibit a similar pattern in their static properties. These bearings need a particular construction to support radial forces because of their unique physical characteristics, which include low dynamic viscosity and high density. Their spiral and feedback grooves are crucial components for heat dissipation and hydrostatic throttling. This article can serve as a reference for the lead–bismuth bearing's lubrication theory.