Research On Measurement And Control Technology Of Water Lubricated Bearing Test Bench Of The Reactor Coolant Pump

Water lubricated bearings is the key technology that restricts the development of nuclear power in China.The performance test of water lubricated bearings for the reactor coolant pump has important theoretical and engineering value for the design and manufacture.At present,in order to realize the localization of the design and manufacture of water lubricated bearing of the new reactor coolant pump,it is urgent to design a complete and perfect measurement and control system of the water lubricated bearing test bench.Firstly,the structure and performance test parameters of water lubricated bearing are introduced.The theoretical calculation and test methods of performance parameters are especially analyzed.On the basis of demand analysis,the overall design of the measurement and control system of the water lubricated bearing test bench is carried out.In order to ensure the accuracy of water film thickness measurement before the test,the position sensor calibration subsystem is designed.As part of the whole system,a switching controller composed of fuzzy controller and PID(Proportional-Integral-Derivative)controller is used to make an accurate and rapid control over the internal temperature and solve the control problem of the temperature and large hysteresis of the calibration temperature.The calibration curve is fitted based on the least squares method,and the result is directly fed back to the measurement and control system of the water lubricated bearing test bed for correcting the test data.The design of the whole system is based on virtual instrument technology.According to system requirements analysis,the hardware system consists of the NI chassis and the multi-function PXI data acquisition card which form the data acquisition and control module.The software of the system is based on the LabVIEW to design and develop various functional modules.In order to reduce the noise impact,algorithms such as low-pass filter and mean filtering are used to improve the accuracy of the data.The test data is transmitted to the on-site LED display in real time through TCP/IP protocol,and is managed through the Access and the TDMS database.The completed system is applied to the actual site,and the functional test is carried out on the engineering prototype.The experimental results show that the designed system can meet the performance test requirements of water lubricated bearing of the reactor coolant pump.Aiming at the limitations of water film thickness monitoring during the actual operation of the reactor coolant pump,the soft sensor modeling of water film thickness is studied based on the large amount of data collected.The soft sensor model of water film thickness is established based on the experimental temperature,flow,pressure,load and rotational speed by using the neural network.The test results show that the soft sensor model of water film thickness based on neural network has better nonlinear approximation ability and meets the actual monitoring requirements.