Mathematical modeling and numerical simulation of the buckling stability behavior of hybrid beam

Variable Bleed Valve (VBV) as the core component of aero-engine compressor airflow control plays a vital role in eliminating the risk of booster stall during transient conditions and is an important foundation to ensure the stable operation of the engine and the flight safety of aircraft. In this paper, the VBV of a certain engine is studied to build its function model and carry out the system simulation analysis based on AMESIM. Secondly, the control system simulation model is established by using MATLAB and aircraft Quick Access Recorder (QAR) data. In combination with the function model and the control model, the working characteristic curve of VBV is analyzed and compared with the actual working characteristic curve of the engine. The results show that the variation trend of the simulation characteristic curve is consistent with the real characteristic curve, which fully verifies the accuracy and reliability of the VBV functional model.

Function Modeling and Simulation Analysis of Aero-engine VBV

Sun¹,

Xu²

2023

Exploration of Key Technologies of Intelligent Inspection Robots in the Application of Automatic Energy Meter Verification Line

Jin¹,

Zhang²,

Cheng³

et al. 2023

There are many drawbacks and inconveniences in the application of human power in the energy meter calibration line. In order to achieve a standardized level of operation and to improve the efficiency and quality of the automated meter testing line, this paper applies the intelligent inspection robot to the automated meter testing line and discusses the key technologies involved. Based on the texture characteristics of the screws on the energy meter cover, a screw coordinate positioning method based on the texture center of gravity method is designed as a machine vision technique for intelligent inspection robots. Based on the feedforward controller transfer function and feedback system open-loop transfer function, combined with PI controller, a feedforward-feedback composite servo position control strategy is designed to complete the release action of the robot end controller. Pressure sensor on the robot end claw controller, integrated servo drive with current sensor. The Kalman filter method of static estimation is used to fuse and process multi-source data information to realize the grasping action of the robot end controller. The test results of the key technical performance and economic and time benefits of the robot show that the recognition success rate and grasping success rate of the robot for energy meters are as high as 100%, and it takes a total of 54s to complete each grasping and releasing action. The maximum error in each direction is 4.9mm, 5.2mm and 5.1mm respectively, and the maximum error in angle is only 1.25 degrees. The working manpower is reduced by as much as 93.16%, the average expenditure of inspection cost is only 1.24 yuan, and the floor space is reduced to 700 square meters. In summary, the study can ensure a high level of consistency in the quality of energy meters, improve the efficiency of calibration and production, and create greater economic benefits while providing a solid technical guarantee for the large-scale construction and stable and reliable operation of the power grid.

Development of Particulate Matter Monitors based on Light Scattering Method

Liu,

Yu,

et al. 2023

+86 10 64525036 PM2.5 and PM10 measurement technique based on light scattering usually exhibit inaccurate measurement results in their applications. For improving the reliability of this method for PM2.5 and PM10 measurement, systematic research on the structure optimization of single particle light scattering sensors (SPLSS), calibration of SPLSS, and PM2.5/PM10 monitor development are carried out. Frist, by simulating and optimizing light scattering parameters, light scattering signals varied monotonically with particle size could be obtained, and thereby capability of accurate size-identifying can be established. Then, by developing threshold comparison circuit and calibration device, particle size channel of SPLSS or monitor could be divided, and particle counting efficiency could be corrected. Finally, by obtaining empirical values of parameters, i.e., heating temperature, particle density, involved in the developed dynamic heating system and PN-PM algorithm, interference of humidity and particle characteristics can be effectively eliminated, thus particle mass concentration (PM) could be calculated according to particle number concentration (PN) in each channel. The results show that the developed monitor has good accuracy by comparing it in atmospheric air with reference methods of PM2.5/PM10.