Research on Eccentricity Performance of Capacitance Rod Position Measurement Sensor for Measuring Non-Metallic Rod

Rod position measurement sensor is the key equipment of control rod hydraulic drive line, the measurement accuracy of the sensor is directly related to the safety and reliability of the reactor. Capacitance rod position measurement sensor is generally composed of excitation and detection electrodes, ceramic tube, outer shielding layer and measuring rod. For the double helix capacitance rod position measurement sensor with non-metallic measuring rod, the static characteristic experiment of the sensor was completed, the finite element method was used to establish the calculation model and the model was verified by the experimental results. By the calculation model, the influence of electrode angle, pitch, thickness and relative permittivity of ceramic tube on the eccentricity error of the sensor was systematically analyzed, the optimal combination of design parameters were obtained by orthogonal test method. The results show that the calculation results are in good agreement with the experimental results, the eccentricity error can be reduced by reducing the electrode angle, increasing the electrode pitch, increasing the thickness and reducing the relative permittivity of the ceramic tube. The design scheme of the sensor obtained by the orthogonal test can greatly reduce the eccentricity error and realize the requirement of rod position measurement without losing step. The research results provide guidance for the design and optimization of capacitance rod position measurement sensor.

In situ growth of a tubular MoS2 membrane on a ceramic tube with improved organic solvent nanofiltration performance

A MoS2 tubular ceramic membrane was prepared successfully via a straightforward in situ hydrothermal method and demonstrated excellent organic solvent nanofiltration properties and high stability.

Radial Vibration Characteristics of Piezoelectric Ceramic Composite Ultrasonic Transducer

Different from the existing equivalent circuit analysis method of the transducer, based on the vibration theory of the mechanical system and combined with the constitutive equation, this paper analyzes the radial vibration characteristics of the transducer. The piezoelectric ceramic composite ultrasonic transducer is simplified as a mechanical model of a composite thick wall tube composed of a piezoelectric ceramic tube and a metal prestressed tube. The mathematical model of radial vibration of the transducer is established, which consists of the wave equation of radial coupling vibration of the piezoelectric ceramic tube and the metal prestressed tube, the continuity conditions, and the boundary conditions of radial vibration of composite thick wall tube. The characteristic equation and the mode function of radial vibration are derived. The calculated results of natural frequency are in good agreement with the existing experimental results. Based on the analytical method and the difference method, the numerical simulation models of radial vibration are established, and the amplitude-frequency characteristic curves and the displacement responses are given. The simulation results show that the amplitude-frequency characteristic curves and the displacement responses of the two methods are the same, which verifies the correctness of simulation results. Through the simulation analysis, the influence rule of the transducer’s structure sizes on its radial vibration natural frequency is given: when the thickness of the metal prestressed tube and the piezoelectric ceramic tube are constant, the natural frequency decreases with the increase of the inner diameter of the piezoelectric ceramic tube; when the outer diameter of the metal prestressed tube and the inner diameter of the piezoelectric ceramic tube are constant, the natural frequency decreases with the increase of the thickness-to-wall ratio. The calculation method of natural frequency based on elastic vibration theory is clear in concept and simple in calculation, and the simulation models can analyze the mechanical vibration of the transducer.