Axial piston pumps are essential hydraulic power components widely used in aerospace for their compact structure and high efficiency. High-speed axial piston pumps face more demanding dynamic challenges due to extreme operating conditions such as high rotational speed and small displacement, which may lead to instability including cylinder block tilting. This study establishes a dynamic rotor-assembly model consisting of the main shaft, cylinder block, and key tribological pairs, and develops an offline multi-condition spline stiffness model to enhance computational stability and efficiency. The tilting behavior of the cylinder block under different operating conditions is analyzed, and the influence of shaft deflection on tilt response is further examined. The results provide guidance for the design and optimization of high-performance, high-speed axial piston pumps.

In response to the issue of power reduction in wind farms caused by wake interference from wind turbines, an experimental platform was designed and constructed in a wind tunnel to study the wake and power characteristics of wind turbines, with a focus on the wake characteristics of a single turbine under yaw conditions and the power characteristics of wind turbines arranged in series. The results indicate that when wind turbines operate under yaw conditions, their wake recovery is accelerated, the wake centerline is shifted, and the wake width is narrowed. These characteristics allow the use of yaw wake control methods to enhance the total output power of wind turbines arranged in series, with the total power of the series being increased by up to 18% when the upstream turbine's yaw angle is set at 25°.

As a crucial shut-off device in industrial pipeline systems, the sealing performance of globe valves under vibration conditions is directly related to the safe and stable operation of the system. The study investigates the sealing condition of globe valves in a vibration environment by combining numerical simulation, theoretical analysis, and dynamic tests. The sealing performance of the sealing structure is analyzed, the key factors affecting the sealing performance are discussed, and targeted optimization suggestions are proposed. Finally, definite research results are obtained and core conclusions are drawn: the quantitative relationship between the contact pressure of the sealing pair, the sealing surface gap and the vibration parameters is clarified, the main failure modes and critical thresholds of sealing under vibration conditions are determined, the structural parameters, material properties and vibration working conditions are identified as the key factors affecting the sealing performance, and the effectiveness of the multi-method combined research is verified. Moreover, the proposed optimization suggestions can significantly improve the sealing reliability of globe valves. This research aims to provide theoretical support and application guidance for the installation, sealing and maintenance of industrial pipeline systems.

Electrical proportional valve is a key component of pneumatic technology in aviation field, and its set output pressure determines the aircraft rudder surface manoeuvre, which in turn affects the flight performance. In order to study the influence of the rudder surface proportional valve on the aircraft attitude and heading operation performance, based on fuzzy PID, PSO optimization PID and other control strategies, the application of AMESim-Simulink carries out multidisciplinary joint simulation to comparatively study the dynamic and static characteristics of aviation electrical proportional valves, and optimie the system regulation strategy to achieve stable and precise control, so as to ensure the advantages of the overall flight control efficiency. The results show that: fuzzy PID control than particle swarm algorithm optimization PID control valve system rise time reduced by 1.84%, the amount of overshooting reduced by 52.46%, adjustment time reduced by 20.52%, the comparative study of fuzzy PID control strategy makes the electric proportional valve control efficiency optimal, so as to build a control system with fast response, high robustness and self-resistant control system, electrical proportional valve practical engineering application research is of great significance.

Taking the valve body under high temperature and high pressure as the research object, the temperature and thermal stress of the valve body are calculated by the finite element software, and the dangerous area of the valve body is determined. The influence of stress triaxial value variation on multi-axis creep factor E value during valve body operation period is analyzed. Using Hayhurst model, Huddleston model and Huddleston model modified by multi-axial creep factor E, the equivalent uniaxial stress trend curve of the valve body is calculated. On the basis of Larson-Miller theory, three stress combination models were used to calculate the valve body damage and creep fatigue life in one operating cycle, and the modified Huddleston model was found to have the maximum safety margin.

An analytical model for an oblique wing torque motor of two-dimensional valves is proposed to address the problem of the lengthy and complicated optimization design process using finite element simulation. The analytical model is established based on the equivalent magnetic circuit method, in which the leakage effect of the permanent magnet and the permeability nonlinearity of the soft magnetic material are taken into account. A prototype of the oblique wing torque motor was designed and manufactured, and an experimental platform was set up to test the torque-angle characteristics and torque-displacement characteristics of the oblique wing torque motor. The analytical results are compared with the experimental results, the accuracy of the analytical model is verified.

A real-time monitoring scheme for dual tank water level based on virtual instrument technology is proposed to address the common problem of liquid level regulation in modern industrial control processes. A dual tank water tank experimental platform was constructed, and corresponding mathematical models were established based on it. Use MATLAB Simulink for numerical simulation and control the dynamic and static characteristics of the system based on the simulation results. The application program of the dual tank water level control system was developed using LabVIEW software, and efficient integration of hardware and software was achieved by combining USB-6008 acquisition card and DAQ data acquisition assistant. Visual monitoring of liquid level changes has been achieved through a designed human-computer interaction interface. The experimental results show that the developed system interface can present the real-time trend of liquid level changes, and the deviation between the actual liquid level curve and the simulation results is kept below 2%, and the error with the real liquid level is also controlled within 3%. The effectiveness of the proposed method has been verified, providing a new control method for industrial water tank liquid level control.

Smoke collection bin is located below the storage cabinet distribution vehicle and connected to it. It is used to collect and temporarily store the smoke that falls during operating the distribution vehicle, and clean the smoke by connecting with an external negative pressure suction device. Flow field uniformity in smoke collection bin has a significant impact on cleaning efficiency and effectiveness, and stomatal arrangement in air distribution plate is an important factor affecting the flow field uniformity. Therefore, a study is conducted on the influence of stomatal arrangement in air distribution plate on its flow field uniformity. Numerical simulation was analyzed on the flow field uniformity of six types of air distribution plate stomatal arrangement structures, and the simulation results was verified through experiments. The results show that, under the premise of consistent opening area, the air distribution plate with a diameter of 10 mm has better flow field uniformity than the air distribution plate with a diameter of 15 mm. Under the premise of keeping the aperture constant, a dense opening in the middle of the air distribution plate and sparse openings around it will increase the uniformity of flow field on the surface of air distribution plate, the denser openings in the middle and the sparser openings around it will get better uniformity. On the contrary, it will reduce the uniformity of the flow field on the surface of the air distribution plate.

In hydraulic system of miter gate hydraulic hoist of Yangtze River lock, the balance valve plays a key role in ensuring the stability and safety of the system. In order to study which structure of the balance valve needs to be optimized to make it more suitable for the actual working conditions of the miter gate hydraulic hoist system, this study establishes a three-dimensional model of the balance valve, and then imports the three-dimensional model into Fluent software. The internal flow field of the balance valve was numerically simulated in detail. The fluid pressure distribution, flow characteristics distribution and turbulent kinetic energy distribution of the balance valve under different opening degrees are analyzed. The results show that the pressure distribution of the force surface of the spool will be dynamically adjusted with the flow field conditions. The flow field distribution reveals the fluid flow characteristics, and the turbulent kinetic energy is mainly concentrated at the tail and both sides of the force surface of the spool, and gradually attenuates along the flow direction. These analyses provide an important reference and basis for the structural optimization and design of the balance valve.

In order to clearly understand the dynamic characteristics of the fuel metering system in commercial aero-engines, achieve the simulation solution for the dynamic change process of fuel pressure, and obtain the response characteristics of various state variables within the system, the component models of the fuel metering system are simplified and a force analysis is conducted. Subsequently, the mathematical equations of each functional module of the fuel metering system are established. These equations are then combined to form a system of equations, and a dynamic simulation model of the fuel metering system is constructed based on Simulink. By comparing with the experimental data, the rationality and accuracy of the system simulation model are verified. Based on this system simulation model, an analysis of the influence of different damping of the high-pressure shut-off valve on the fuel system pressure fluctuation was completed. The results indicate that the system dynamic simulation model can simulate the fuel metering system pressure change process in a manner close to physical reality. The fuel pressure change process before and after the metering valve is opened is similar to the experimental results. As the damping of the high-pressure shut-off valve increases, the displacement variation amplitude of the high-pressure shut-off valve decreases. Meanwhile, at the moment when the high-pressure shut-off valve is opened, the peak fuel pressure in front of the valve increases with the increase in damping.

To effectively cope with parameter uncertainty and external interference in steam heat exchangers, reduce control overshoot, and improve the stability of intelligent control of steam heat exchangers, an intelligent air-frequency domain joint control method for steam heat exchangers is studied. Extracting spatial basis sequences of steam heat exchangers using principal component analysis method; using spatial basis sequences to convert the spatial set values of parameters such as temperature, pressure, and flow rate of steam heat exchangers, and obtain the set values of a low dimensional model; using the error between the set value and the actual value as the input data for an incremental fractional order PID controller, a joint spatial frequency domain incremental fractional order PID controller is designed to obtain the incremental control quantity of the steam heat exchanger; by analyzing the phase amplitude frequency and phase angle characteristics, the open-loop frequency domain characteristic constraints of the steam heat exchanger are designed. Combined with the performance requirements of minimum overshoot, the parameters of the incremental fractional order PID controller are tuned and optimized to effectively cope with parameter uncertainty and external interference in the steam heat exchanger, and improve the stability of intelligent control of the steam heat exchanger. Experimental results have shown that this method can effectively extract spatial basis sequences of steam heat exchangers; this method can effectively and intelligently control steam heat exchangers; in a variety of external disturbances, the control overshoot is less than 2.9%, the lowest can be up to 0.0%, far better than the comparison method, at the same time, the controller can quickly respond to changes in the set point, the steam flow and water supply temperature stabilization time of 3 min and 5 min, respectively, in the heat exchange efficiency of 90% of the industrial heat exchanger to achieve the key parameters of the precise control, and effectively reduce the energy consumption and the risk of failure.

A digital control strategy based on frequency-domain correction is proposed to address the load matching challenges of electro-hydraulic servo systems under complex working conditions. By analyzing the phase lag characteristics of the servo valve-controlled hydraulic motor system in the low-frequency range, it is revealed that traditional PI control suffers from insufficient phase margin in the low-frequency domain. Innovatively, a composite correction method combining a first-order low-pass filter and a second-order notch filter is adopted: a first-order low-pass filter is constructed to compensate for the phase lag, while a second-order notch filter is designed to suppress the resonance peak. A digital simulation platform was built using MATLAB, and the filter parameter matching algorithm was optimized through pole-zero configuration. Experimental results demonstrate that this technique effectively mitigates the issue of insufficient phase margin in the low-frequency domain and suppresses the resonance peak in the high-frequency range. The experimental data verify that the method significantly improves the dynamic tracking capability of the electro-hydraulic servo system, providing a novel solution for the digital hydraulic control of engineering machinery.

The erection mechanism is crucial for ground equipment for rockets, missiles, and other installations, driven by a multi-stage cylinder to rapidly erect heavy loads to a specified position. In response to the rapid response and stability requirements of the erection frame, this study investigates the rapid and stable erection control technology of multi-stage erection cylinders based on acceleration planning, resulting in an improved sinusoidal S-curve trajectory. A model of the erection system was constructed in AMESim for simulation verification, and the results obtained indicate that the sinusoidal S-curve trajectory designed in this paper can effectively reduce the impact of startup and gear shifting, meeting the rapidity and stability requirements of the erection system.

In order to improve the performance of hard-to-hard friction pair of mechanical seal under extreme working conditions, diamond coating technology was used to modify the seal ring. Based on CVD method, the wear resistance of diamond coated seal ring was verified by comparison of grinding and polishing time, pressure running test and third party test data. The obtained diamond-coated silicon carbide seal ring has higher wear resistance; After 8 hours of operation, check that the flatness of the sealing ring is less than 0.000 6 mm and the leakage change is small; Compared with the third party test, the surface hardness of the CVD diamond film coated is about 3 times higher, and the surface friction coefficient of the sample is 1/5 of the friction coefficient of the uncoated surface. This paper proves that the diamond coated seal ring has longer grinding time, better dynamic operation sealing performance, higher detection hardness and lower friction coefficient.

To address issues such as operational difficulties and low efficiency in auxiliary welding when using expansion tools for the borrowing of storage, transportation, and launch containers, research and design were conducted on internal support structures based on low-pressure gas drive. The rational and reliability of the design have been determined through theoretical analysis and experimental verification, providing new ideas and methods for the subsequent manufacturing of storage and transportation launch boxes.

Common failure modes of large shaft diameter mechanical seals for liquid ring vacuum pumps are analyzed, combining equipment characteristics and operating conditions, it improves the mechanical seals by measures such as sealing ring deformation control and transmission mechanism optimization. Tests have proven that under the working conditions where the seal shaft diameter is no more than 280 mm, the linear velocity is no more than 10 m/s, the pressure ranges from 0 to 0.8 MPa, and the sealing medium is clean water or light oil, the improvement is reasonable and effective, and the operating stability of mechanical seal is significantly improved.

The design of the gas source isdirectly related to the success of failure of the quantitative liquid timing filling function of the Gas-driven liquid filling system. Aiming at the gas source energy and filling time concerned in the design of gas-driven liquid filling system, the characterization and test scheme of the filling time are put forward, and the test piece design is completed basing on the analysis of the filling mechanism. The filling tests were carried out with filling medium of water, the filling time under different pressures were obtained, and the feasibility of characterizing the filling time by pressure change curve was verified, and the law of pressure changing with filling time was obtained. Based on the design size of test product and the physical properties of the filling medium, the numerical simulation of filling process under different pressures was carried out, and the critical gas source pressure and filling time under different pressures were obtained. The experimental results and numerical simulation results are analyzed. The results show that the difference between the critical gas source pressure determined by numerical simulation and the critical gas source pressure obtained via experiment is small, while the variation of simulated filling time with pressure is similar to that of the experimental filling time, with an exponential changing trend. Results here verify that the function of timing filling of quantitative liquid can be realized through rational design of air source energy.

In order to study the influence of the release valve discharge timing of the supercritical carbon dioxide power system on the work performance, the simulation analysis of the supercritical carbon dioxide power system is carried out, and the correctness of the simulation results is verified by experimental tests. the results show that the speed and acceleration of the load can be adjusted by changing the discharge timing of the release valve, and on the premise of satisfying the speed, the discharge timing can be adjusted to reduce the acceleration of the load during movement to achieve smooth movement, and ensure the stability of the device whin the load.