Degradation behavior analysis of electro-hydraulic servo valve under erosion wear

2013 ◽  
Author(s):  
Kun Zhang ◽  
Jinyong Yao ◽  
Tongmin Jiang ◽  
Xizhong Yin ◽  
Xiaobo Yu
Keyword(s):  
Behavior Analysis ◽  
Degradation Behavior ◽  
Erosion Wear ◽  
Servo Valve ◽  
Hydraulic Servo

Particle motion and erosion morphology of the spool orifice in an electro-hydraulic servo valve under a small opening

2021 ◽  
pp. 095440622110349
Author(s):  
Xinqiang Liu ◽  
Hong Ji ◽  
Fei Liu ◽  
Nana Li ◽  
Jianjun Zhang ◽  
...  
Keyword(s):  
Wear Rate ◽  
Particle Motion ◽  
Particle Diameter ◽  
Pressure Differential ◽  
Erosion Wear ◽  
Particle Rotation ◽  
Small Opening ◽  
Servo Valve ◽  
Typical Particle ◽  
Hydraulic Servo

To explore the spool orifice’s particle motion and erosion morphology in an electro-hydraulic servo valve under a small opening, a modeled particle motion visualization test and CFD calculation were conducted to study typical particle trajectory. The influence of pressure differential, particle shape, and particle diameter on the erosion rate along the working edges was discussed. The erosion characteristic morphology and working edges’ fillet diameter distribution were measured and analyzed. There are four typical particle motions: translation and spin on the wall faced the flow, translation and turn on the backflow wall, carried motion by the mainstream and particle rotation in a vortex. A model of the erosive particle motion of the spool orifice was built based on the visualization test and CFD. During these motions, the microscopic scraping and collision of particles with the working edges are the main causes of erosion wear. The erosion wear rate of the working edge is proportional to the pressure differential and the non-roundness of the particles. The fillet of a working edge periodically increases or decreases with the circumferential angle, which occurs due to the morphology and is consistent with the erosion wear rate distribution along the working edge.

Research on the Impact Pressure of the Hydraulic Rolling-Cut Shear

2010 ◽  
Vol 145 ◽  
pp. 410-413 ◽  
Author(s):  
Jing Wang ◽  
He Yong Han ◽  
Qing Xue Huang ◽  
Jun Wang
Keyword(s):  
Hydraulic System ◽  
Impact Pressure ◽  
Direct Impact ◽  
Actual Situation ◽  
Work Situation ◽  
Servo Valve ◽  
Indirect Impact ◽  
Hydraulic Servo ◽  
Hydraulic Servo System ◽  
The Impact

The reasons for impact pressure are obtained by the research the hydraulic system of Hydraulic Rolling-Cut Shear. The impact pressure of hydraulic system is divided into direct impact and indirect impact. Based on analyzing the actual situation the measures should be taken to reduce the impact pressure when design hydraulic system. The suitable length of pipeline can improve the performance of the hydraulic system because the length is important for the impact pressure. The accumulator can absorb impact pressure and improve the work situation of servo valve. Therefore, the suitable accumulators should be set in the hydraulic system. The study provides theory basis for the pipe design of large hydraulic servo system.

Visualization of Flow-Field between the Flapper and Nozzle in a Hydraulic Servo-Valve

2011 ◽  
Vol 402 ◽  
pp. 407-411 ◽  
Author(s):  
Jacob M. Mchenya ◽  
Sheng Zhuo Zhang ◽  
Song Jing Li
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Video Camera ◽  
Computer Assisted ◽  
Servo Valve ◽  
High Speed Video ◽  
High Speed Video Camera ◽  
Hydraulic Servo ◽  
Working Principle ◽  
Computer Assisted Image

In order to understand the mechanism and get rid of the high-frequency self-excited noise in a hydraulic servo-valve, in this paper, the flow field distribution in the pilot stage of a hydraulic flapper-nozzle servo-valve is investigated. An assembly is prepared representing the construction and working principle of the flow field inside the pilot stage of a hydraulic flapper-nozzle servo-valve. A method of visualization is developed by taking videos for the flow field inside the transparent assembly with a high speed video camera. In this study, at different inlet pressure the high speed video camera was utilized for flow visualization together with computer-assisted image measurement. The shape of the jet flow, the cavitations and vortex flow inside the flow field can be visualized clearly. The proposed method enables to analyze the flow-field in the pilot stage of a hydraulic flapper-nozzle servo-valve by giving useful information for better design.

Study on Flow-Shifted Region Depending on Spool Displacement in Hydraulic Servo Valve with Hybrid Lap

2013 ◽  
Vol 37 (3) ◽  
pp. 213-219
Author(s):  
Hwang-Hun Jeong ◽  
So-Nam Yun ◽  
Sung-Soo Lee ◽  
Joo-Ho Yang
Keyword(s):  
Servo Valve ◽  
Hydraulic Servo

scholarly journals Research on the Dynamic Erosion Wear Characteristics of a Nozzle Flapper Pressure Servo Valve Used in Aircraft Brake System

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yuanbo Chu ◽  
Zhaohui Yuan ◽  
Wenchao Chang
Keyword(s):  
Service Life ◽  
Life Prediction ◽  
Wear Behavior ◽  
Prediction Method ◽  
Service Life Prediction ◽  
Dynamics Simulation ◽  
Brake System ◽  
Erosion Wear ◽  
Wear Characteristics ◽  
Servo Valve

The nozzle flapper pressure servo valve is a kind of high-precision hydraulic component that can be widely used in the aircraft brake system. In actual service, the dynamic erosion wear behavior will occur at the pilot stage because of the gradual contamination of oil and the variable distance between nozzle and flapper. For this purpose, the paper proposes a dynamic erosion wear characteristics analysis and service life prediction method in which firstly the structural feature and working principle of the nozzle flapper pressure valve are analyzed using the brake cavity as the load blind cavity. Secondly, the dynamics simulation model and the performance experiment system of the pressure valve are separately constructed, and then the validation of the constructed model is conducted by contrasting the results between simulation and experiment. Finally, the mathematical models of the degradation process induced by the dynamic erosion wear are established, and then the dynamic erosion wear characteristics under dynamic structural distance and contamination conditions are analyzed, which are combined with the failure threshold value determined by the dynamics simulation to finish the service life prediction of the nozzle flapper pressure servo valve.

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