The Particle Image Velocimetry (PIV) was used to study the wake flow field characteristics and the vibration characteristics of rectangular blunt body (length-width ratio of 1/2) with Reynolds number Re ranging from 3018 to 10 565 and cantilever spacing s=3D. The experimental results were analyzed by using the Proper Orthogonal Decomposition (POD). The results show that the energy content of the first two POD modes in the blunt body wake is the maximum and the modal frequency is the same, which reflects the large-scale Carmen vortex structure. The modal frequency is vortex shedding frequency. The larger the modal energy content is, the greater the amplitude of the cantilever beam in the wake is; The root-mean-square amplitude y_rms and the dominant vibration frequency f_b of the cantilever beam in the blunt body wake of rectangular cylinder increase linearly with the increase of Re. The first two POD modes are used to reconstruct the wake flow field, and the reaction of the cantilever beam on the flow field structure and the vibration mechanism of the cantilever beam in the rectangular blunt body wake are revealed.

The processing quality of micro texture on the end face of the sealing ring plays a crucial role in the performance of mechanical seals. Laser engraving is currently one of the commonly used methods for processing textures on end faces. To investigate the influence of laser processing parameters on the depth of texture grooves and the roughness of groove bottoms, a fiber laser marking machine was employed to study the laser processing techniques of silicon carbide sealing rings. Using the method of controlled variables, we sequentially adjusted parameters such as laser Q-frequency, laser power, marking speed, filling spacing, marking times, fill angle, fill type, to analyze the influence of different process parameters on the quality of texture processing. The results indicate that various parameters have varying degrees of influence on the processing of microtextures, with key parameters being laser Q-frequency, laser power, and marking times, followed by marking speed, filling spacing, and filling angle, while filling type has a relatively weak effect.

In order to improve the reliability and accuracy of rock drilling jumbos in the construction of uneven ground in the mine, a method of automatic leveling of rock drilling jumbos is proposed. The transfer function of hydraulic control system of rock drilling jumbos is studied. Based on the optimization algorithm, the co-simulation of automatic leveling control system is carried out by using AMESim-Simulink. By comparing the control effects of various improved strategy particle swarm optimization (Particle Swarm Optimization, PSO) optimization algorithms, the chaos and self-adaptive particle swarm optimization PID control strategy is ultimately selected, It realizes the rapid erection and precise positioning of the leveling platform of the body of the drilling platform. The control system is stable, the overshoot is small and the leveling speed is fast. It provides a certain reference value for the engineering application of automatic leveling system of drilling rig and other mine equipment.

In order to effectively reduce the energy consumption of traditional excavators during operation, this paper innovatively proposes a design scheme for a boom energy recovery system based on a balance cylinder and an accumulator. Firstly, a force analysis was conducted on the hydraulic cylinder of the excavator boom, and it was found that the energy recovery efficiency varies with the angle between the boom hydraulic cylinder and the horizontal plane. Using AMESim to establish simulation models for traditional hydraulic systems and energy recovery hydraulic systems, the simulation shows that under the same operating conditions, the motion speed and displacement of the boom hydraulic cylinder piston rod coincide. This indicates that the introduction of the designed energy recovery system has minimal impact on the operational performance of the excavator, almost negligible. During one cycle of excavator boom operation, compared with traditional hydraulic systems, the addition of an energy recovery system reduced energy consumption by 43.31% and hydraulic pump displacement by 49.23%.

In order to solve the problems of slow processing speed, low product accuracy and uncoordinated operation of actuator of desktop 3D printer, a pneumatic extrusion control system based on STM32 single chip microcomputer was proposed. The hardware circuit and software control of the pneumatic extrusion control system are designed to realize modular integration, including temperature detection, pneumatic motor control and other modules. Fuzzy-PID algorithm is adopted, and the closed-loop control of the driving system is realized, so that the temperature of the extruder and the action of the actuator are precisely controlled, and the accuracy of the positioning of the print head is improved. The research shows that the control system can reduce the printing error within 0.3% and shorten the cycle by more than 50%.

The continuous transportation system consists of multiple sets of hydraulic driven equipment distributed over long distances, which use multiple sets of load sensitive proportional multi way valves to control the dispersed hydraulic actuators. Multiple sets of load sensitive proportional multi way valves adopt a series oil supply method, supplied by a hydraulic pump station. We have improved the design of a new connection block (inlet oil connection) for load sensitive proportional multi way valves, making it more suitable for series connection of load sensitive proportional multi way valves with multiple long distance dispersed arrangements. This not only improves the control response speed of the actuator, but also simplifies the pipeline of the hydraulic system.

Due to the complex working conditions of the high-pressure reciprocating sealing system and the frequent sealing failures, the performance of large-scale hydraulic equipment is seriously restricted. In this study, the reliability analysis and structural optimization of the reciprocating sealing system were carried out based on CAE analysis and orthogonal test methods. Firstly, a two-dimensional symmetric finite element model of the reciprocating sealing structure was constructed, and the influence of the medium pressure, prepressure and sealing clearance of the sealing system on the performance of the high-pressure reciprocating sealing was simulated and analyzed, and the critical pressure of extrusion at the root of the sealing ring was obtained as 28 MPa. Then, the influence of the key structural parameters of the Y-ring on the sealing reliability was analyzed by the orthogonal test method, and the optimal structural parameters of the Y-ring were determined, and finally the optimized structural parameters were verified by the CAE method. The results show that the optimized structural parameters can effectively control the extrusion of the root of the sealing ring, and can reduce the maximum contact pressure and maximum equivalent stress of the seal, which can effectively improve the reliability of the Y-shaped reciprocating sealing structure under the background of high pressure.

This paper describes the powerful application of Solidworks software in the design of hydraulic manifold after the development of secondary libraries. Based on the design requirements of hydraulic mainfold, a special library for hydraulic manifold design was developed. It is verified based on actual cases. The results show that the proposed method significantly improves the flexibility and convenience of the software in the design of hydraulic manifold, and achieves the intelligent, efficient, accurate and fast drawing effect of the design. This technological advancement not only reduces the mental burden of technical designers, but also simplifies the heavy and complex drawing review workflow. At the same time, the design efficiency and the accuracy of the drawings are improved, and the software support role is played a strong role in improving product quality, reducing costs and increasing efficiency.

This paper aims at the problem of imbalance flow in bleeding air system of a type of aircraft found in flight test, performs root cause analysis basing on the flow distribution principle of multi-source parallel pipeline network, provides bleed air system design proposal according to root reason, and verifies the design using AMESim and CFD software. The results show that the flow difference between the multi-source parallel pipeline bleed air systems can be controlled within 10%.

Electromagnet is the key part of the hydropneumatic control system. The electromagnetic force is the most important parameters that directly determines the open and close processes of the electromagnet. The crucial parameters that affect the electromagnetic force is numerically studied using a Maxwell 3D code. The numerical model of the electromagnet is validated by experimental data. The impact of component fit clearance and coil temperature on electromagnetic force is investigated. The results show that electromagnetic force decreases with the increase in component fit clearance due to the magnetic leakage. This phenomenon indicates that it is of great significance to consider component fit clearance for the prediction of electromagnetic force. Moreover, the increase in coil temperature results in a considerable decrease in the electromagnetic force, which may hinder the open and close processes of the electromagnet.

According to the testing requirements of the hydraulic laboratory, a universal hydraulic valve test bench has been designed and developed, and its installation interface covers ISO4401, ISO7789 and other standards, and the testing capacity meets the conventional tests of pressure valves, directional valves, flow valves and other valves. This article introduces the working principle, composition structure, control system design, and application cases of the test bench. By analyzing the test content of various hydraulic components, determining the relevant technical parameters of the test bench, designing the hydraulic system principles of each workstation of the test bench, designing the control system based on the hydraulic system test process, and developing the IPC software. Finally, through the testing of a directional valve, it was verified that the functions of the test bench meet the testing needs.

The objective of this study is to conduct a comprehensive and systematic analysis of the impact of stem roughness and packing type on the sealing performance of valves. The objective of this study is to investigate the comprehensive effects of stem roughness on the sealing, friction, and leakage rate of globe and ball valves. To this end, the sealing performance and friction performance of valve stems with different roughness (Ra0.2, Ra0.4, Ra0.8, Ra1.6, Ra3.2) and four packing types were tested. The test results demonstrate that stem roughness has a significant impact on the sealing and friction properties of the packing material. The lowest leakage rate was observed in globe valves with a roughness of 0.4 μm, while the smallest leakage rate was observed in ball valves with a roughness of 1.6 μm. Furthermore, the impact of diverse packing materials on friction and leakage rate varies. Packing type C exhibits the most optimal performance across all indices. It was determined that stem roughness and packing type are the primary factors influencing the sealing performance of the valve. This provides invaluable data support and a theoretical foundation for valve design optimization. This study is of significant practical value for enhancing the operational stability of valves, extending their service life, and improving equipment performance.

High pressure gas supply system (HPGSS) is widely used in aerospace, aviation, shipping, chemical, pharmaceutical and other industries, and has an irreplaceable role. This paper introduces the design scheme of the system. control strategy and application of new technology, and analyzes and summarizes the current research situation of high pressure gas. In the HPGSS engineering, the selection of high pressure parts is the most important task. The development of the HPGSS and advanced technology such as computer technology and automatic control technology complement each other and promote each other. The controller in the HPGSS has more powerful function and more precise control, and the control strategy is developed from the traditional on-site control mode to the digital and intelligent remote control mode. Finally, the future development trend of the HPGSS is discussed.

This paper analyzes the issue of spring fracture within the landing gear switch, reaching the conclusion through failure analysis that the spring sustained a fatigue fracture. Theoretical assessments confirm that the spring's fatigue strength and lifespan meet the requirements under three distinct states within the cavity, the root cause of the spring fracture is attributed to the unreasonable sizing of the support washer, which leads to the spring's bottom getting hooked on the oil hole groove of the washer and the washer being gnawed. This results in abnormal force application on the spring, stress concentration, and ultimately, fatigue fracture. Based on the fault cause, improvements were made to the design of the support washer's size. Theoretical calculations were conducted for flow resistance, and simulation analyses were performed on the static strength and fatigue strength of the washer. Experimental validation was carried out by processing test pieces, and the improvement effects met the expected outcomes. The revised design has broad application prospects and offers certain reference value for addressing similar fracture failures encountered in engineering projects.

In view of the problems such as the closed slewing system adopted by the existing hydraulic excavator, the slow acceleration in the starting and braking stages, the high control pressure and large impact generated by the debugging of the existing control mode, the constant torque control system using the motor end pressure is designed with the 100 t hydraulic excavator as the research object and the existing closed slewing system as the basis. Through simulation and experimental verification, the new system can reduce the maximum operating pressure of the system, reduce the speed fluctuation during the starting braking process, and maintain the maximum rotation speed, providing better handling performance and energy saving.

This article takes the A4V series plunger pump as an example to study and solve the problem of leakage and oil return in plunger pumps in hydraulic transmission systems. The root causes of oil leakage and return problems include internal seal failure, high oil temperature, and unreasonable structural design, which not only affect the efficiency of the pump, but may also lead to chain reactions such as high oil temperature and seal damage. Based on the working principle and leakage return mechanism of the plunger pump, the author proposes an improvement plan by combining the principles of forced cooling and forced lubrication. The internal fluid flow of the inclined plate pump and inclined shaft pump is redesigned to reduce leakage flow and improve pump efficiency. Based on the working principle and leakage return mechanism of the plunger pump, the author proposes an improvement plan by combining the principles of forced cooling and forced lubrication. The internal fluid flow of the inclined plate pump and inclined shaft pump is redesigned to reduce leakage flow and improve pump efficiency. The research content and results related to the article have important guiding significance for the improvement design of plunger pumps.

With the escalating of domestic non highway machinery technology, hydraulic transmission oil has also been upgraded. The friction performance and shifting performance in hydraulic transmission oil will continue to improve with the extension of the drain period. However, the friction durability is indeed the most difficult to balance and achieve in the hydraulic transmission oil formula system. So it is particularly important to maintain friction durability throughout the entire oil change cycle. This article focuses on the characteristics of copper based friction plates commonly used in non highway mechanical transmission clutches in China. It simulates the friction characteristics and durability evaluation method of wet clutch copper based friction plates, which helps to study the friction characteristics and durability performance of clutches suitable for non highway mechanical transmissions in China.

This article analyzes the problems with the original mechanical seal of a screw expansion power machine in a large domestic chemical enterprise, and proposes to transform the mechanical end face seal into a dry gas seal. Based on the performance characteristics of the dry gas seal layout, this screw expansion power machine uses a double end dry gas seal produced by a domestic sealing enterprise. This article mainly describes the design process and parameters of dry gas seals, analyzes their working mechanism, calculates the sealing performance, draws relevant curves, and finally obtains various parameters that affect the dry gas seal performance, such as pressure, temperature, speed, and film thickness. In addition, the design methods and control ideas of the auxiliary control system for dry gas sealing were also elaborated. After the manufacturing of the complete set of dry gas sealing equipment is completed, simulation tests need to be conducted on the dry gas sealing test bench to verify the reliability and accuracy of the dry gas sealing design. Install the dry gas seal after leaving the factory for testing on the production site, and conduct application assessment under long-term service conditions. The dry gas seal operates stably, the auxiliary control system of the dry gas seal is safe and reliable, and the dry gas seal meets the design requirements. The successful transformation of the dry gas seal of the screw expansion power machine ensures the stable operation of the equipment, eliminates the hidden dangers caused by medium leakage, and has good application prospects for the expansion of dry gas seal technology.

In response to the short service life and large leakage volume of traditional bearing housing seals, a magnetic mechanical seal structure was designed that relies on magnetic force to provide closing force. The design, material selection, force analysis, and face pressure calculation of the magnetic mechanical seal structure were determined to determine the components and dimensions of each component. The experimental results show that the magnetic mechanical seal functional components are few, the structure is simple, and the installation and use are convenient. The leakage rate is less than 1 mL/h, the wear rate of the rotating ring is less than 0.35 μm/h, and it can replace oil seals and be used in traditional bearing housing seals, which has good practical application value.