Numerical Simulation and Optimization Analysis of Labyrinth Screw Pump in Nuclear Power Reactor Coolant Pump

In order to improve the wear phenomenon caused by cavitation on the surface of the thrust bearing in a certain nuclear power plant and extend the service life of reactor coolant pump, it is considered to add a second-stage labyrinth screw pump to the lubrication circuit of the thrust bearing in the reactor coolant pump. By installing a pressure boosting device, the circuit pressure is increased and cavitation is reduced. In this paper, the three-dimensional model of the first-stage labyrinth screw pump in the reactor coolant pump is established, and the numerical calculation is carried out by using FLUENT software to analyze the pressure, velocity and temperature distribution of the flow field. The calculation results are compared with the actual operation results of the nuclear power plant to verify the accuracy of the model and the numerical calculation method. A second-stage labyrinth screw pump is designed and numerically simulated. It is found that after adding the second-stage labyrinth screw pump, the pressure rise at the inlet and outlet of the lubrication circuit is 3.30×10⁵ Pa, the head is increased by 33.67%, and the temperature rise at the inlet and outlet section is 3 K. The research results have a certain reference value for the design and application of labyrinth screw pump in engineering practice.