核主泵流体动压型机械密封辅助密封圈有限元模型与性能分析

The Finite Element Model and Performance Analysis of the Secondary Seal Ring in Hydrodynamic Mechanical Seals of the Reactor Coolant Pump

机械密封是核电站反应堆冷却剂泵的关键部件。某核主泵机械密封运行过程中,产生了第三级密封前压力下降和密封泄漏量增加的现象。为分析根本原因,采用有限元软件建立了核主泵流体动压型机械密封辅助密封圈的二维轴对称模型。分析了辅助密封圈在安装状态、正常工作压力及全系统压力下的位移分布、Mises应力分布和接触压力分布,研究了密封介质压力对密封圈变形、应力和接触压力的影响规律。结果表明:现有的辅助密封圈能够在正常工况下起到密封作用;辅助密封圈与插入件直接接触,产生了微动磨损;挡圈与插入件间存在间隙,没有发生磨损的可能;辅助密封圈位移、Mises应力、接触压力和接触宽度随密封介质压力的增加而增大;挡圈避免了辅助密封圈被挤入间隙内而损坏。

The mechanical seal is the key component of the reactor coolant pump in nuclear power plant.During the operation of a primary coolant pump,the pressure before the third-stage seal decreased and the leakage increased.A two-dimensional axisymmetric finite element model of the third-stage secondary seal for hydrodynamic mechanical seals of the reactor coolant pump was established based on a finite element software.The deformation behavior and contact mechanism was analyzed at the state of the installation stage,normal pressure and full system pressure.The influence of the sealed pressure on deformation,Mises stress distribution,contact width and contact pressure were studied.The results show that the secondary seal plays a sealing role under normal working conditions;the secondary seal contacts with the insert part of the seal,which causes the fretting of the metal insert part;there is a gap between the retaining ring and the insert part,so there is no possibility of wear between the retaining ring and the insert part.The displacement,Mises stress,contact pressure and contact width of the secondary seal increase with the increasing sealed pressure.The retaining ring prevents the extrusion of the flexible secondary seal and damage.