Research On The Design And Implementation Of An Impeller Deformation Measurement System Based On PSD

Turbine, which converts the thermal energy and kinetic energy to the electrical energy, is the prime mover of the thermal power and the nuclear power plants. The impeller is an important part of the turbine. A large elastic deformation would occur when it works. If the deformation is above a certain threshold, the impeller would collide with the internal components of turbine, which could cause huge losses. In order to provide a safe and reliable operation of the impeller, high-precision deformation measurement sensor is needed to analysis the deformation of the pressurized impeller before it is put into use.Laser deformation sensor is widely used in various industrial fields, like aerospace, automation, and electronics etc., due to some distinct advantages, such as good repeatability, high precision, and wide range of applications, etc.. However, China is dependent on the expensive imports of this high-precision deformation measurement sensor. In this thesis, a deformation measurement system based on the PSD(position sensitive detector) is designed and developed. The main works are as follows:1. Based on the analysis of the existing development methods of deformation measurement system, the functional requirements and the technical indicators for the impeller deformation measurement system are proposed. The overall design of the impeller deformation measurement system is implemented, which includes the design of the deformation measurement sensors, the design of the free movement mechanism and the design of the system measurement software.2. The working principle of PSD and the laser triangulation method is analyzed. Based on the laser triangulation measurement method and the scheimflug condition, the optical parameters of the laser deformation sensor is designed and developed. The analog and digital signal processing circuits of PSD are designed and developed, which include the TMS320F28335 core circuit, the I/V conversion circuit, the amplifier circuit, the filter circuit, the bias circuit, the ADS1256 acquisition circuit and the LD driving circuit. The system circuit board is designed and developed with good circuit layout and anti-jamming system.3. According to the requirement of this project, a compact free movement mechanism is designed and developed.4. The AD acquisition program is developed on the software platform of CCS3.3 and a deformation measurement software system is designed and implemented. Software approaches are used to remove the background light and the dark current.5. In order to test the accuracy and precision of the deformation measurement system, an experimental platform is developed. The deformation measurement sensor is calibrated by using an optical grating platform. A series of experiments on the deformation measurement system are implemented. The main sources of errors are analyzed and the corresponding solutions are given.