Research On The Measurement And Control Technology Of Key Parameters Of Nuclear Pump Manufacturing Process Based On CPS Principle

Nuclear power as a low carbon energy source can effectively reduce carbon emissions and is gaining more and more attention.As a key core equipment in nuclear power plants,the nuclear pump is the key to highly reliable and safe and stable operation of nuclear power plants.For the shaft seal main pump of the third generation nuclear power technology to achieve 60 years of operation during maintenance-free high reliability technology requirements.The static and dynamic data from the design and verification of the main pump and the water film condition are essential for the re-optimisation of the design,the digital modelling and the active preventive maintenance of the nuclear main pump during future in-service operation.To this end,an Cyber Physical System(CPS)architecture was designed for the nuclear pump production process based on the CPS,in particular,the software measurement technique for the bearing water film thickness and the control method for the water film pressure parameters were studied in depth,for which the research in this thesis is as follows:Firstly,the principle of shaft seal type nuclear pump and radial sliding bearing is analysed,and the Reynolds equation of fluid flow and the influencing factors and mechanism model of radial sliding bearing fluid film thickness are analysed according to fluid lubrication theory.The analysis of the measurement and control technology requirements for the nuclear pump testing process is completed,the information and physical system architecture for the nuclear pump production process is constructed,and the CPS system for the nuclear pump testing process is designed in conjunction with the CPS5 C level architecture(5C level architecture).Secondly,to address the complex and many factors affecting the water film thickness of nuclear pumps,the high requirements for prediction model accuracy and real-time data acquisition,and the unmeasurable characteristics of nuclear pumps in service operation,a soft measurement model for water film thickness of water-lubricated bearings is established based on stochastic configuration network(Stochastic Configuration Network,SCN).The parameters such as radial load on the bearing,water film pressure on the bearing,heat loss from bearing friction,flow rate and rotational speed are used as auxiliary variables in the SCN prediction model to achieve prediction of water film thickness.The experimental results show that the SCN-based water film thickness model has good prediction accuracy and can meet the real-time monitoring of water film thickness of shaft seal type water-lubricated nuclear pumps.Finally,for the uncertainty interference of the bearing film pressure,the high accuracy required for the supply pressure parameters,and the requirement to simulate the ultimate operating condition during in-service operation,which requires the interaction with parameters such as speed at the specified time,a supply pressure controller based on finite time control is designed for such characteristics,which introduces a time-varying constraint function to transform the original tracking control problem into a delayed constraint problem of tracking error The controller is designed to avoid uncontrollability.The stability analysis of the controller is completed and the simulation results show that the finite-time control has stronger anti-interference ability and higher tracking accuracy than the traditional sliding mode control,and the response time is faster to meet the requirements of the test process parameters.