推力瓦热瞬态变形机理及抑制方法研究

针对核主泵水润滑推力轴承在事故工况下的热瞬态过程,建立了热固耦合瞬态有限元分析模型。基于所建立模型,分析了常见两层和三层结构推力瓦热瞬态过程瓦面变形,重点分析了三层结构推力瓦隔热层厚度对瓦面变形的影响。随后,进一步探索了遏制瓦面凹变形的方法,阐明了热瞬态过程中瓦面温度场分布不均是产生瓦面凹变形的主因。进一步提出一种新型包边式推力瓦,并仿真验证其能够有效降低热瞬态过程瓦面凹变形,为核主泵水润滑推力轴承的推力瓦设计提供了新思路。

Research on Thermal Transient Deformation Mechanism and Suppression Method of Thrust Pad

Water lubricated thrust bearings in reactor coolant pumps (RCP) experience thermal transient processes during the accident conditions. A thermal-solid coupling model is developed for the thermal transient processes by finite element method. Based on the developed model, conventional double-layer and triple-layer thrust pads are analyzed to obtain the surface deformation during the thermal transient processes. In particularly, the effect of the thickness of heat insulation layer in triple-layer pad on surface deformation is discussed. Subsequently, several suppression methods to reduce the concave deformation of the pad surface are analyzed. The simulations indicate that the leading mechanism of forming the concave deformation is the uneven distribution of tile surface temperature field during the thermal transient processes. With this understanding, a new type of thrust pad having the edge of the thrust pad surface wrapped is proposed, which is verified by simulation to efficiently reduce the concave deformation during the thermal transient processes. This work provides a new thought to design the thrust pad of the water lubricated thrust bearings in RCP.