Stream limiter is an important component of the steam generator in nuclear power plant, which plays a necessary role to ensure the safe operation of the reactor. Based on the CFD numerical simulation method, the flow field characteristics and key performance of two mainstream venturi steam restrictors are compared.The results show that the flow limiting capacity of the nineteen⁃nozzles is 6% higher than that of the seven⁃nozzles,and the pressure loss is only 67.3% of that of the seven⁃nozzles. Research results of this work can be a reference for stream limiter's design and model selection.

A high efficiency and high precision testing method for tightness detection method of aluminum foil seal is proposed.First of all, the thermal images of aluminum foil seal are obtained by a thermal imager.Then we use MATLAB software for getting the information of thermal image in batches,and then the image preprocessing. Then BP neural network was optimized by genetic algorithm to extract and classify image features.The experimental results show that this sealing test method has high recognition rate and short training time, which provides a guarantee for automatic screening and elimination of bad sealing products in the subsequent aluminum foil sealing production line.

In order to study the vibration characteristics of the downhole gear transmission system,based on the 3D modeling software CREO, a three⁃dimensional geometric model of the main and driven gears of the downhole gear transmission system was established. And using the ANSYS software import function to establish the three⁃dimensional finite element model of transmission gear. By reading the dynamic mechanical modal analysis of the finite element model of gear, the natural frequencies of the gears and the corresponding main modes are obtained. This study can be used as a theoretical reference to avoid the frequency of external excitation response in the design process, so as to avoid the resonance of the transmission system and effectively improving the fatigue strength of the gear transmission system.

A method for detecting the integrity of aluminum foil seals with high detection accuracy and high detection efficiency is proposed.First of all,in order to obtain the infrared image of the sealing part aluminum foil,the method has adopted the infrared imaging technology.Then，the infrared image is preprocessed and the feature is extracted by circular symmetric Gabor wavelet.Lastly,KNN is used to identify and classify the acquired imaging.Experiments show that the circular symmetric Gabor wavelet used by this sealing detection method has higher recognition rate and faster algorithm than the traditional Gabor transform algorithm, and provides technical assurance for the automatic screening and rejection of defective sealing products in the subsequent aluminum foil sealing production line.

Reducer as an important transmission, there is a very wide range of applications in many areas. A new design of reducer for oil pumping unit in oil field was introduced, and the modeling, assembly and simulation analysis of Pro/E software was used. The interference of gear running was obtained by position simulation, and the operation condition of internal gear of reducer was directly reflected. The drive ratio was verified through kinematics simulation| through dynamic simulation, the force of the mechanism was obtained, and the vibration condition of the mechanism was obtained by the force analysis. Direct application of Pro/E simulation could greatly improve the design efficiency.

        After the research on the distribution characteristic of temperature field for aluminum seal , a kind of inspection method for the sealing based on Gabor transformation and extreme learning machine (ELM) was proposed. The Gabor transformation was conducted on various thermal images ，and the textural features are extracted to train the ELM neural network. Then the training results are used to classify and identify the thermal images， and the sealing of aluminum seal could be judged through the classification features of the thermal images. Compared and analysed with BP neural network which extracts color features，it is found that the algorithm based on Gabor transformation and ELM has the advantages of strong generalization，fast response speed，high precision，etc.

The space more freedom position control system is studied for the simulation experiments which provide experimental device space more freedom need space of X、Y axis roll and pitch motion. The system selects the siemens S7300 PLC as lower computer, the WinCC as upper computer. The control system used the modular programming design thought, timer interrupt for a long timing, PID control of electrohydraulic proportional valve opening to make the simulating platform pitch and roll motion of the fast track come true, and the failure to make the solution in the process of debugging.

Based on the flexible rotor testbed as the research object, used DASPv10 analysis software to simulate the rotor imbalance and misalignment of two typical faults, the mechanism analysis were made for the collected signal from the eddy current sensor and the piezoelectric acceleration sensor. The experiments gave the timedomain analysis, frequencydomain analysis and axis path diagram in the case of normal and fault two cases，compared the experimental results with the theoretical analysis. It verified the two typical fault identification features of rotor vibration, making a better understanding of the fault mechanism and fault diagnosis of the rotating machinery system. 