Designing Grading Circulation To Improve Oil Purification Capacity For Ground Maintenance System

Contaminants in hydraulic oil may shorten the trouble-free service life of aviation hydraulic systems and reduce the maneuverability and durability of aircraft.This is particularly important when air transport and fighter jets perform missions.Ground maintenance is the only way to reduce oil pollutants.However,the existing ground oil purification device adopts a single purification method,which cannot meet the requirements of purifying different pollutants at the same time.In order to improve the working capacity of the ground maintenance system and improve the efficiency of oil purification.In this paper,combining cyclone-filtration and vacuum-centrifugal purification methods,it is proposed to classify solid pollutants according to the critical purification diameter,and design a ground maintenance system to purify the solid particles of different particle sizes,water and gas pollutants.Design a hierarchical circulation ground maintenance purification system.The closed elastic oil tank is designed to store hydraulic fluid and stabilize the pressure of the ground maintenance system,and the applicability of the closed elastic oil tank is measured through simulation experiments.The cyclone-filtration purification device is designed to purify solid particles with a diameter of d>50 μm in the hydraulic fluid,and the purification efficiency of it is evaluated.The vacuum-centrifugal purification device is designed to purify solid particles,water and gas pollutants with a diameter of 50 μm ≥d>5 μm in the hydraulic fluid.And integrate the above three devices into the ground maintenance system to achieve cyclic purification.Performing static and kinematic analysis of the purification device verify the feasibility of the structural design.According to the force characteristics of the fuel tank,the static strength of the inner and outer shell of the fuel tank is checked by ANSYS,and the response time of the closed elastic fuel tank is analyzed by MATLAB.Under the influence of the peak load of hydraulic oil,the stress change of the centrifuge barrel of the vacuum-centrifugal purification device is verified,and the critical speed and corresponding vibration shape of the centrifuge barrel is explored.Under the condition of optimizing the experimental parameters,the purification efficiency of the cyclone-filtration purification device on solid particles is analyzed under different flow rates.The bearing system,sealing system and oil transmission pipeline in the auxiliary parts is designed to realize the connection between the various devices.In the bearing system,the lower bearing is a thrust ball bearing,and the upper bearing is a deep groove ball bearing.After checking,the bearing system meets the design requirements.The sealing system is designed to isolate the connection between the external environment and purification system.The O-ring structure is used inside the system to prevent fluid leakage;the V-shaped sealing ring structure is used outside the system to prevent foreign contaminants from entering the system.Using ANSYS to simulate and analyze the stress change at the weak link in the hydraulic pipeline,the analysis result shows that the maximum stress at the slot on the pipeline is less than the allowable stress,which meets the safety requirements.