Dynamic Simulation Of Lubricating System In Secondary Loop Of Marine Nuclear Power

The marine nuclear power secondary loop system with high operating power and strong endurance has become a project of competitive development at home and abroad.As an important auxiliary system to ensure its normal operation,whether the stable and dynamic performance of the lubricating system is good or not will have a crucial impact on the safety and reliability of the secondary loop system.Due to the lubricating system in secondary Loop of marine nuclear power has the characteristics of complex structure,the strong coupling of the flow network and the variable resistance characteristics,the current research on the lubricating system is mainly focused on the analysis and description of the system’s steady performance,the lubrication characteristics of the single equipment’s component and the dynamic characteristics of the local system,but there are relatively few studies on the overall dynamic performance of the system.This paper focuses on the dynamic performance of the lubricating system in secondary loop of marine nuclear power in order to provide corresponding technical support for the design and development of the system.In this paper,the simulation model of the lubricating system in secondary loop of marine nuclear power is set up with the aid of the GSE software.According to relevant design data,the steady performance of the system under high and low operating conditions is verified to ensure that the simulation model has high calculation accuracy.Based on this model,the dynamic characteristics of the lubricating system under varing operating conditions of the power plant,the non-uniformity of the lubricating oil’s temperature of various devices and the effect of different control strategies on the adjustment of the lubricating system’s pressure was simulated.In addition,the low-pressure protection process of the lubricating system was studied and analyzed in the case of the leakage of the main oil pipe.The simulation results show that: when the load is reduced from 1st working condition to the 3rd working condition and 5th working condition,the overshoot of the main oil pipe’s pressure is 1.4% and 2.8% respectively,and the flow of the lubricating oil is respectively reduce by 3.5% and 7.2%;when the load is increased from 5th working condition to 3rd working condition and 1st working condition,the minimum value of the mian oil pipe’s pressure is 0.986 and 0.972 respectively,and the flow of the lubricating oil is respectivelyincreased by 3.94% and 7.74%;the change in proportion of the heat loss of the each device in the lubricating system and the readjustment of the relationship for the flow distribution caused by it are the main causes for the non-uniformity of the lubricating oil’s temperature;compared with the single-impulse PID control,the three-impulse PID control has a good control effect on the pressure of the lubricating system and siginificantly shortening the stabilization time of the pressure;when the instantaneous leakage flow of the main oil pipe is 5%,by quickly adjusting the opening of the inlet steam valve of the main oil pump’s turbine and increasing the speed of the main oil pump,the pressure of the main oil pipe is adjusted to the initial stable value,the overshoot of the main oil pipe’s pressure is 2%,its stabilization time is about360 s and maximum time that the lubricating system can maintain stable operation is 27minutes;when the instantaneous leakage flow of the main oil pipe is 10%,the electric oil pump starts automatically,causing the system to run into the over-pressure state,the maximum value of the main oil pipe’s pressure is 1.356 and its stabilization time is 300 s,the maximum time that the lubricating system can maintain stable operation is 19 minutes,which provides a basis for whether the power system can continue to operate and the further post-processing operations in an emergency.