Analysis of submerged bearing eccentricity on support characteristics of molten salt pump for thorium nuclear power system

Abstract

BackgroundWith the development of thorium molten salt reactor nuclear energy system (TMSR) from experimental reactor to research, demonstration and commercial reactor, its shafting evolved into the slender flexible rotor supported by submerged bearing. High temperature molten-salt pump is the main power device of TMSR, its stability and reliability are critical to the submerged bearing support characteristics.PurposeThis study aims to analyze bearing eccentricity on support characteristics of high temperature molten-salt pump for TMSR.MethodsThe numerical simulation method in Beperf module of DyRoBeS software was used for the theoretical calculation and analysis of the submerged bearing. Combined with experimental verification, the influences of various eccentricity on the supporting characteristics of the bearing were studied.ResultsThe results show that the eccentricity of the bearing decreases with the increase of rotational speed. With the augmentation of eccentricity, the orthogonal stiffness and damping of the bearing is increasing continuously, so are the cross stiffness and damping. Conversely, the thickness of minimum liquid film reduces continuously. The bearing pressure ends up with zero and zero gradient due to the attenuation of the minimum liquid film thickness when the eccentricity is greater than 0.6.ConclusionsIt is verified that the liquid membrane invalidation brings about serious wear of the bearing in actual operation, and this study provides theoretical guidance and experimental data support for the design of the submerged bearings of ultra-high temperature long shaft molten-salt pump.

Keywords

• high temperature molten salt pump
• submerged bearing
• eccentricity
• liquid film thickness
• supporting characteristics