Analytical and Experimental Research on Reactor Coolant Pump Mechanical Seals With Hydrodynamic Deep-Grooves

Hydrodynamic mechanical seal with deep grooves is used on reactor coolant pumps (RCP) of KSB SE. It has several good features, such as simple structure, excellent wear resistance, low pressure leakage rate, etc. In this paper, an analysis method across different calculation platforms is used to analyze the RCP mechanical seals. The finite element analysis based on ANSYS is to simulate the thermal deformation of mechanical seal rings, while an algorithm based on Reynolds equation with JFO cavitation boundary is used to evaluate the seal film, which is less than 1 μm thick. A specific test rig was built up to carry out the operational test for RCP mechanical seals. In this test rig, full pressure, normal temperature and rotary speed can be achieved, meanwhile some special conditions can be simulated, e.g. thermal impact, pressure drop, and loss power. The internal pressure, flow rate, temperature, and rotary speed can be detected in-situ. The low-pressure leakage rate is the flow through the gap between seal faces, which is the most important operational parameter to represent the tribological features of seal faces. In this test, the low-pressure leakage rate can be detected by a weight-based measurement system. After 200 hours test, all detecting parameters kept constant. The detected low-pressure leakage rate was around 80 mL/h, which has good consistency with the analysis results.