The aeroengine boasts a complex structure and operates in a demanding environment characterized by prolonged exposure to extreme conditions such as high temperature and pressure. This type of system is susceptible to nonlinear faults. To enhance the accuracy of aeroengine predictions, this paper proposes a fault diagnosis model based on stacking-based ensemble learning. Initially, the KNN algorithm (K-Nearest Neighbor) and the AdaBoost algorithm (Adaptive Boosting) are optimized by hyperparameters to further augment the accuracy of a single model. Subsequently, the XGBoost model is employed as a meta-learner to fuse the prediction outcomes of the optimized KNN and AdaBoost models. The stacking ensemble learning technique is then applied, followed by the output of the prediction results. Through confirmatory experiments, the accuracy rate following stacking integrated learning improved to 0.9591, while the standard deviation was further minimized to 0.0074. The findings demonstrate that the model is remarkably precise and robust, and can be implemented in aeroengine fault diagnosis.
A numerical model has been developed to investigate the dynamic characteristics of the Superconducting electrodynamic suspension (EDS) system. Modeling of the guideway with the surface irregularity and the Maglev vehicle are described. Numerical simulations were performed in Simulink to solve the coupled problem. A 3-D model of the electromagnetic system of the superconducting EDS train is established, and the computed real electromagnetic forces are coupled with the maglev train. The EDS train was simulated by using the SIMPACK multi-body dynamic program. The simulation was carried out by using two body models of rigid and flexible bodies. In order to use the modal information to construct the flexible car body, the finite element method and the ABAQUS software were used to construct it together with equivalent elements. The final framework is constructed in MATLAB/Simulink to simulate dynamics and electromagnetic forces together with the constructed simulation framework. In order to consider the interference caused by irregularities, randomness and power spectral density (PSD) are used to analyze vibration interactions. We compared random signal inputs with PSD, greatly enhancing accuracy, and analyzed the vibrational interaction between car body and ride quality.
The electrostatic precipitators are widely used in power plants and other energy fields.The invention discloses a device for on-line processing short circuit fault of the electrostatic precipitator electric field without stopping, which comprises the robot installed on the top shell platform of the electrostatic precipitator, and the robot is controlled and connected with the monitoring device outside the electric field, so that the monitoring device can remotely control the robot wirelessly moving inside the electric field of electrostatic precipitator to the short-circuit fault point of the electric field. The device can effectively solve the serious problem of electric field short circuit caused by cathode line fracture or hypertrophy and the problems of time-consuming, laborious, high cost and serious pollution, so as to achieve the purpose of cost saving, quality improvement and efficiency.
To study the influence of cigarette gas on the environment, it is necessary to know the cigarette gas flow fields from burning end. By using PIV technique, in order to reveal velocity characteristics of gas flow fields, the velocities of cigarette gas flow fields was analyzed with different stepping motor frequencies corresponding to suction pressures, and the trend of velocity has been given with image fitting. The results shows that the velocities of the burning end increased with suction pressures; Between velocities of the burning end and suction pressures, the relations present polynomial rule; The cigarette gas diffusion in combustion process is faster than in the smoldering process.
Based on stepping motor system and the law of fluid continuity, PIV technique was used to measure mainstream flow field in cigarette smoke directly, and the cigarette outlet velocity was obtained at different stepping motor frequencies with different suction pressure. The results show that the velocities increase with the different suction.
Superconducting electrodynamic suspension (EDS) train has the unique advantages of excellent levitation and guidance stabilities, large levitation gap, and so on. All of these merits make it a promising candidate for the future ultrahigh-speed transportations. In order to explore the dynamic characteristics of the EDS system with a figure-eight-shaped coil (ground coil), this article transforms the complex electromagnetic field coupling between the superconducting magnets and ground coils into a reduced circuit relationship based on the dynamic circuit theory. Meanwhile, the motion characteristics are introduced to establish the field-circuit-motion-coupled model. In this article, a faster and more convenient semianalytical method was proposed to solve mutual inductance. First, the dynamic circuit model of a single-sided figure-eight-shaped null-flux EDS system was established. The magnetic coupling calculation was carried out between the onboard superconducting magnets and ground coils by a semianalytical method. Furthermore, the time-step iteration method was utilized to solve the induced current governing equation of the ground coil under different operating conditions. The energy method was employed to find the transient solution of the levitation force, guidance force, and drag force. Second, the field-circuit-motion-coupled model was validated by the experimental data of MLX01 on the Japanese Yamanashi testline. To investigate the influence upon the suspension and guidance caused by the different connection types of figure-eight-shaped coil, a cross-connected EDS train dynamic circuit model was built. Finally, based on the field-circuit-motion-coupled model, the essential parameters affecting the stability of the system were explored, and the characteristics of the system when vertical or lateral displacement occurs were calculated and analyzed. The achievements of this article can provide a reference for the design of the EDS train for future even higher speed transportation.
The electrostatic precipitator noumenon usually has about ten manholes, and the inside of the manholes is the electric field with tens of kilovolt. Therefore, the safety of electrostatic precipitator manholes is particularly important. At present, most electrostatic precipitator manholes only use a single electronic or electrical safety interlock protection. These methods are feasible in principle, but they are not suitable for the bad operating environment of electrostatic precipitators, such as high temperature, high voltage, strong interference, strong corrosion and so on, and the above ways still have high operating costs, difficulty in maintenance and repair, and poor system stability and low safety. This paper aims at the above-mentioned technical and security issues existing in the current electrostatic precipitator manholes and provides a new type of safety lock unit and interlocking device for electrostatic precipitators. The device herein has been used the brand-new design concept which achieves electrical safety interlocking through mechanical interlocking, and it guides people to operate the equipment properly and eliminates the adverse consequences caused by human factors, fundamentally preventing the occurrence of fatal accident such as electric shock. The device herein has many advantages such as simple structure, easy installation, convenient use, high temperature resistance, corrosion resistance, stable operation, high security, reliability and durability, so it has high practical value and promotion value.
As a promising candidate for future high-speed transportation, the superconducting electrodynamic suspension (EDS) train have drawn a lot of attentions from the academic and industrial communities in the past decades. The dynamic response of EDS train is one of the key aspects that determines the safety and ride quality. In this work, the essential issue of EDS vehicle/guideway system dynamics is studied, including the magnet/rail interaction and the dynamic characteristics. The electromagnetic forces were provided by electromagnetic interaction between on-board superconducting magnet (SCM) and ground levitation/guidance coils in a null-flux superconducting EDS system. These forces were studied as a research premise for dynamic characteristics analysis of EDS train based on the vehicle/guideway coupling dynamics. A dynamic numerical model, with vehicle/guideway coupling dynamics of EDS system, was established to investigate its dynamic characteristics. The frequency and acceleration responses of the carbody in terms of the electromagnetic forces irregularity at different traveling speeds are presented and analyzed. The result indicates that superconducting EDS train can steadily run over the straight line at a speed of 600 km/h, meeting the riding comfort standard ISO2631.
There are many hidden troubles in the ash-slag disposal system of electrostatic precipitator. If the accidents are not found and treated promptly, they will lead to too much dust in ash hopper, resulting in serious accidents such as electric field short-circuit and chain conveyor tension fracture. The accidents can cause the entire plant to stop and overhaul, and the task to deal with them is troublesome, time-consuming and labor-intensive, high-polluting and high-costly. In view of the above problems, the paper provides a automatic fault detection and alarm device for the ash-slag disposal system of electrostatic precipitator in order to detect and deal with the related faults in time. The device mainly uses a plurality of sensors to automatically detect the parts such as ash hopper, rotary valves, chain conveyor and all drive motors and send the detection signals to the controller in real time. If the measured value of any part is abnormal, the controller will send out the acousto-optic alarm signals and display the fault information accurately so that the duty personnel can discover and deal with it in time and prevent accident enlargement. The device has the advantages of simple structure, high sensitivity, high reliability and high practical value.
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