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    Volume 47,2022 Issue 12
    • Flow Characteristics of Dynamic Pressure Gas Bearing with Interface Slip
      ZHANG Jingyang; SUN Yijian; LV Yuanwei; LUO Xinyang

      Abstract:In order to reveal the flow mechanism of the dynamic pressure gas bearing under the partial slip state and the effect on the bearing performance,the modified Reynolds equation considering the partial slip was established and solved with over relaxation iteration by coupling film thickness equation.The effects of slip state,eccentricity,gap size and coupled elastic foil on the gap film flow characteristics were numerically analyzed.The results show that the slip state of the fluid-solid interface has a significant effect on the rotor and stator gap flow and the bearing performance.Rotor side slip occurs in the pressure rise zone,which reduces the pressure in the high pressure zone.The stator side slip occurs in the pressure drop zone,which increases the pressure in the high pressure zone.Compared with the case of no slip,the interstitial gas film pressure peak value is increased by 12% during local slip.Within the parameters of this paper,as the eccentricity decreases and the gap height increases,the slip state of the gap interface gradually changes from the dominant rotor side slip to the dominant stator side slip.When the elastic foil is coupled,the slip area is increased by 1 to 4 times,the slip speed is increased by 2 to 8 times,and the gap gas film pressure presents a double peak distribution.

    • Load Sharing Performances of Large-scale Equalizing Beam Thrust Bearings Considering Rotor Misalignment and High-pair Contact Deformation
      ZHANG Fan; YIN Peng; ZHAO Guangliang; LIU Yuyang; WANG Jianmei

      Abstract:For the carrying performance of a large-scale heavy-duty equalizing beam thrust bearing considering the rotor misalignment,the high-pair contact deformation equation and the film thickness equation characterized by pivot film thickness were established respectively.Combined with the adaptive dynamic model of equalizing beam component,the influence of the angle and position of rotor misalignment and the contact deformation of the high-pairs of the equalizing beam assembly on the load sharing performance of the bearing under typical working conditions were studied.The results show that the contact deformation of high-pair materials of equalizing beam components can improve the uniformity of the bearing load to a certain extent,but the uneven load difference will be unacceptable as the inclination angle increases.The performances of equalizing beam bearing under three typical projection positions,i.e.,the axis projection passes through the middle of two pads,the pad centerline and the pad pivot have similar characteristics,and the load sharing capacity of equalizing beam component is not completely shared.There is a critical value φ e for the rotor misalignment angle φ ,when φ>φe,the performance difference of the bearing pads will increase significantly.Therefore,it is necessary to consider the high-pair contact deformation and propose a specification for the maximum constrained inclination angle φ when designing the equalizing beam thrust bearing with large size and large load.

    • Numerical Simulation and Experimental Study on Temperature Field of Hydrostatic Dry Gas Seal
      JIA Yuning; LI Shuangxi; ZHANG Jingbo; SONG Yupeng

      Abstract:The temperature of seal ring ending face is an important factor affecting the performance of hydrostatic dry gas seal,which can directly represent the working state of seal.The temperature field analysis model of the hydrostatic dry gas seal ring was established by solving the heat transfer equation with finite element analysis software,and the temperature distribution and the characteristics of the seal ring end face under abnormal contact conditions and normal working conditions were analyzed.The results show that the temperature of sealing ring end face under abnormal contact condition is about 76.6% higher than that under normal working condition.The temperature of the seal ring end face slightly decreases with increase of film thickness,and the temperature of the seal ring end face significantly increases with the increase of rotating speed.The temperature of the end face slightly reduce with the increase of cavity pressure,and the temperature difference between the end face and the cavity increases with increase of cavity temperature.The influence of temperature field on sealing performance was analyzed.It is found that with the increase of temperature,the sealing opening force increases slowly,while leakage and stiffness decrease.The method of real-time monitoring of seal running state through temperature monitoring was proposed,and the feasibility of this method was verified by experiments.

    • Analysis of Start-Stop Performance of Journal Bearing Considering Different Acceleration Conditions
      GU Chunxing; DAI Li

      Abstract:The friction and wear of journal bearing mainly occurs in the starting and stopping stage.In order to study the tribological performance of journal bearing under start-up condition,a numerical analysis model of mixed lubrication for journal bearings was developed.Reynolds equation with mass conservation boundary condition was used to solve the fluid pressure,Greenwood and Tripp contact model was used to predict the solid surface contact,and Johnson load distribution concept was used to connect the lubrication model and contact model,so as to realize the tribological behaviors of journal bearings from mixed lubrication to hydrodynamic lubrication under start-up and shut-down conditions.By this developed model,the starting and stopping performance of journal bearing system was analyzed under three different lubrication conditions,the boundary lubrication,mixed hydrodynamic lubrication and hydrodynamic lubrication.With the journal bearing system as an example,by combined with different functions of the bearing speed,the influence of the acceleration performance of the bearing on the start-up performance of the bearing was analyzed.The effects of working conditions,oil temperature and bearing structure on the start-up performance of the bearing were studied.The results show that the larger starting acceleration of the bearing can help the bearing enter the hydrodynamic lubrication faster.Higher rotating speed,lower lubricating oil temperature and larger bearing clearance can make the bearing have a better performance in start-up stage.

    • Effect of Double Glow Plasma Copper Infiltration on the Tribological Properties of Cylinder Liner and Piston Ring
      ZHANG Xuecheng; RAO Xiang; LV Yonggang; GUO Zhiwei

      Abstract:In order to study the effect of copper on the tribological properties of cylinder liner-piston ring,copper infiltration modification layers of different thicknesses were processed on the surface of cylinder liner material through the double glow ion infiltration technology.The RTEC multifunctional friction and wear tester was used to carry out the experiments under different loads and lubrication conditions.The friction coefficient during the test,the wear volume and wear surface morphology after test were acquired and analyzed.The effect of copper infiltration modification layer on the tribological properties of cylinder liner material and its mechanism were studied.The results show that the copper infiltration treatment can effectively reduce the friction coefficient of the cylinder liner-piston ring friction pair and reduce the volume of wear.The effect of friction reducing and wear resistance of copper infiltration modification layer is particularly significant under high load and dry friction conditions,the friction coefficient is reduced by 13.15% under high load and 30.86% under dry friction,and the maximum wear volume is reduced by 30.70% and 38.57%,respectively.after copper infiltration,the wear surface of cylinder liner-piston ring is smooth,and a lubricating film layer with high copper content is formed on the friction surface,which has the effect of friction reducing and wear resistance.

    • General Analysis of Point Contact Thermal EHL of High Speed and Heavy Load Spiral Bevel Gear
      HOU Yankun; LIU Zhengang; HU Dunke; WANG Qiuju; LIU Zhenxia

      Abstract:Based on the thermal elastohydrodynamic lubrication(EHL) theory,the lubrication characteristics of spiral bevel gear with high speed and heavy load were analyzed.The variation of two-dimensional profile curves of various characteristics (pressure,film thickness and temperature rise) of bevel gear oil film under different working conditions was studied.The results show that the combination of Hertz pressure peak and secondary pressure peak occurs under the condition of high speed and heavy load,and the classical flat phenomenon of central oil film in EHL is not significant.Only when the temperature decreases and the viscosity of the lubricating oil increases,the flat phenomenon of central oil film gradually appears.In order to improve the lubrication performance of gears by adjusting working condition parameters in engineering practice,the sensitivity of oil film characteristic parameters to input parameters was analyzed.It is found that the influence degree of working condition parameters on the maximum pressure of oil film is in order of elastic modulus,viscosity,rotational speed and power,the influence degree of working condition parameters on the maximum temperature rise and minimum thickness of oil film is in order of viscosity,rotational speed,elastic modulus and power.

    • Simulation Study on Dynamic Characteristics of Tilting Pad Thrust Bearing with Different Curved Surface Parameters
      TIAN Jiabin; WANG Gangwei; WANG Juan; WANG Shengtong; OUYANG Wu

      Abstract:In order to reveal the influence law of the curved surface shape parameters of the pad on the dynamic characteristics of the ship tilting pad thrust bearing,a transient thermo-hydrodynamic lubrication model of the tilting-pad thrust bearing was established,and the calculation method of the bearing stiffness and damping coefficient was studied and verified by the axial disturbance method. Six types of pad surface shapes were designed,and the influence of different types of pad surface curvature on the dynamic characteristics of thrust bearings was simulated and analyzed. The results show that with the increase of excitation frequency,the bearing stiffness coefficient increases and the damping coefficient decreases. Under the same excitation frequency,when only considering the change of the surface shape in one direction,the increase of the value of circumferential surface bulge can increase the oil film thickness and reduce the stiffness and damping coefficient of the bearing. However,the increase of the value of radial surface bulge has little effect on the stiffness and damping coefficient of the bearing. When only considering the radial surface sag,the damping coefficient increases with the increase of the concave amount and can reach the maximum. When both radial and circumferential surface changes are considered,the circumferential bulge is the main factor of influencing the bearing.

    • Numerical Simulation of Plasto-elastohydrodynamic Lubrication Using High Viscosity Oil
      ZHANG Shengguang; LIU Gang; HU Wenying

      Abstract:Aimed at the problem that the calculation results of existing elasto-plastic lubrication models are distorted under the working condition of high viscosity lubricating oil,a plasto-elastohydrodynamic lubrication (PEHL) model was established based on a semi-analytical method.The numerical simulation was successfully carried out through a stepping technique in increasing lubricating oil viscosity,which eliminated the previous fluctuation in the pressure profile in the contact,and overcame the previous problem of calculation distortion.Plastic strain was solved based on J2 flow theory under isotropic strengthening criterion and by radial return algorithm.The residual deformation caused by plastic strain was taken into account in the oil film thickness equation.The results show that the main peak of PEHL pressure is significantly lower than that of EHL,and the pressure spike changes little.The central film thickness for PEHL and EHL models are basically consistent,while the minimum film thickness of the PEHL model is a little higher.The increases in oil viscosity and entraining speed can move the plastic strain region closer to the outlet region and the surface.

    • Steady-state Performance Analysis of Dry Gas Seal with Imitation Tree Groove
      MO Longgang; DING Xuexing; YAN Ruqi; WANG Shipeng

      Abstract:In order to solve the problems of the traditional spiral groove dry gas seal in reverse rotation,such as poor dynamic pressure effect,easy to wear and instability,a new type of bidirectional rotary tree-shaped groove was proposed.SolidWorks software was used to establish the three-dimensional model of gas film,ICEM software was used to divide the grid,and Fluent software was used to simulate the flow field.The opening force and leakage rate of bidirectional rotary tree-shaped groove under different film thickness,groove depth,speed and other parameters were compared with those of the spiral groove.The results show that the tree-like groove can produce obvious dynamic pressure effect and has larger opening force,its leakage rate is higher compared with the spiral groove.When the film thickness is 2 μm and the groove depth is 5 μm to 7 μm,the tree-like groove has better sealing performance.The film thickness and groove depth have a great influence on the sealing performance.The opening force of dry gas seal decreases with the increase of film thickness and increases with the increase of groove depth.The opening force of the two grooves increases with the increase of pressure and speed,but compared with the spiral groove,the sealing performance of the tree-like groove is less affected by the rotation speed and it has a better opening effect.The tree-like groove has good sealing performance while realizing bidirectional rotation,which provides a certain reference for the design of bidirectional rotary dry gas sealing groove.

    • Simulation Analysis and Experiment of Herringbone Groove Liquid Film Seal Based on Multi-Physics Coupling
      REN Baojie*; HAO Muming; HU Guangyang; WANG Mingzhang; SU Zhishan; LI Yongfan

      Abstract:Aiming at the lubrication failure of the contacting mechanical seal of the fuel booster pump,the feasibility of the herringbone groove liquid film seal used in the fuel booster pump was analyzed through multi-physics coupling simulation and experiment.Based on the Reynolds equation considering roughness,energy equation and heat conduction equation,a multi-physics model of liquid film seal was established,and the key performances parameters such as temperature characteristics and leakage characteristics of the seal were analyzed.The sealing performance test was carried out for the herringbone groove liquid film seal.The results show that the average temperature of the herringbone groove seal end face is about 50 ℃ lower than that of the contacting mechanical seal,which is beneficial to the improvement of the seal operation stability.During the test operation,the temperature of the seal is stable,and the leakage is zero,which meets the requirements of the sealing performance for fuel booster pump.

    • Nonlinear Dynamics Effects of Ship Rotor-Floating Raft Airbag System under Sway Motion
      WANG Junwei; LI Ming; XIE Xuan; DU Xiaolei

      Abstract:In order to study the dynamic characteristics of the marine rotor-floating raft airbag system under the sway motion,the mathematical model of the system was established based on the short-bearing theory,and the dynamic behaviors were analyzed on numerical method.The effects of rotor speed,sway amplitude and frequency changes on the nonlinear dynamic characteristics of the system were investigated.The results show that comparing with the system without sway motion,the characteristic of system with is sway motion more complicated.The system is in quasi-periodic motion at the low speed of rotor under sway motion,and as the rotor speed increases,the system bifurcates then merges into a branch until chaos.With the increase of the amplitude of swaying,the vibration amplitude of the rotor increases.However,the increase of the frequency ratio will make the amplitude of the rotor smaller.

    • CFD Analysis of Lubrication Performance of Gear Surface Groove Texture with Consideration of Cavitation Effect
      RENQING Duoji; ZHU Peiyuan; CHANG Xuefeng; LIN Bingjing; SHU Xiayun

      Abstract:In order to investigate the influence of tooth surface groove texture parameters on the lubrication performance of involute spur gears,the gear meshing model was simplified and the unit groove CFD simulation model was established.By solving the two simulation models without and with considering the cavitation effect,the influence rules of different groove dimension parameters on the lubrication performance of the model were obtained.The results show that the distribution state of oil film pressure in the fluid domain changes by the groove texture,and higher oil film bearing capacity and better dynamic pressure performance are obtained.When cavitation effect is not considered,the oil film bearing capacity is closely related to the change of groove width,but is less affected by the change of groove depth.When the groove texture is shallow and wide,the tooth surface has better lubrication performance.When the cavitation effect is taken into account,the surface lubrication performance changes dynamically with the change of groove width and depth.Compared with no cavitation effect,the gear surface has better lubrication performance when the groove width is small and the depth is large.When the groove width and depth are both small,the cavitation effect has a small influence on dynamic pressure performance.When the groove depth is small and the groove width is large,the cavitation effect has a great influence on dynamic pressure performance.While the groove depth is large,the cavitation effect always has a great influence on the dynamic pressure performance,and is not affected by the change of the groove width.

    • Research on Wear of Rubber Rotary Lip Seal Based on Generalized Axisymmetric Model
      LIU Yadong; SHANG Yan; KE Yuchao; XIA Yingsong

      Abstract:The generalized axisymmetric model of rubber rotating lip seals was established.A finite element simulation method was developed at the base of the secondary development of Abaqus/Python and the Abaqus/ALE adaptive meshing technology,whose validity was verified by the experimental results.Compared with the three-dimensional wear model,the new method can significantly improve the computation efficiency at no expense of numerical accuracy.Based on this method,the influence of different working condition parameters on seals was studied.The results show that the wear degree of the air side of the main lip is more serious than that of the oil side in the early stage of wear,and the wear degree of the oil side gradually exceeds that of the air side as the wear time increases.The rotational speed has less influence on the wear,and the main lip contour lines with different rotational speed are roughly parallel at the same wear time.On contrast,the assembly interference has significant influence on wear,but the main lip contour lines under different interference are also roughly parallel.The spring clamping force also has great influences on wear.As the spring clamping force increases,the wear degree on the oil side becomes more severe.

    • Preparation and Friction Properties of Oil Collecting Surface
      WANG Chunying; YI Wenjing; LIU Changsong; LI Xinming

      Abstract:In order to solve the problem of lubrication failure caused by lubricating oil migration and the interrupt of lubricating oil on contact surface,the gradient surface of oleophobic-oleophilic-oleophobic with high oil collecting performance was prepared.A layer of monolayer film was deposited on the surface of silicon wafer by chemical vapor deposition method,and the sample was characterized by contact angle measuring instrument,UMT friction and wear tester,confocal microscope,etc.The lubrication performance of this surface was studied under the condition of limited oil supply.It is found that the oil droplets can move rapidly from the oil-phobic region to the oil-wet region when the oil drops are placed at the oil-phobic/oil-wet junction.The experimental results of point contact reciprocating friction show that the friction coefficient of the silicon wafer with gradient surface is significantly lower than that of the original silicon wafer,and the wear mark depth of the silicon wafer with gradient surface is shallower than that of the original silicon wafer.Various experimental results show that the prepared oil-phobic-oleophilic-oleophobic gradient surface can play the role of oil collection and avoid the problem of lubricating oil interruption.

    • Calculation of Oil Film Pressure and Axis Orbit for Journal Bearings Lubricated with Couple Stress Fluids
      MA Yanyan

      Abstract:The influence of couple stress parameters on the lubrication performance of dynamically loaded journal bearing was studied numerically based on Reynolds equation.The oil film pressure distribution and axis orbit of a certain type of diesel engine bearing were calculated under the lubrication conditions of Newtonian fluid and couple stress fluid respectively.The numerical results show that compared with Newtonian fluid lubrication,the oil film pressure of the bearing increases under the stress couple fluid lubrication,and the maximum oil film pressure appears in the direction of bearing angle increase with the increase of couple stress parameter.Under the two lubrication conditions,the shape of the axis orbit is similar,but the axis orbit is far away from the center of the bearing under the Newtonian fluid lubrication condition,while under the couple stress fluid lubrication condition,the axis orbit is closer to the center with the increase of parameters,and the minimum oil film thickness increases obviously.The research shows that compared with Newtonian fluid lubrication,couple stress fluid lubrication improves oil film pressure and axis orbit,and the larger couple stress parameter is,the more obvious couple stress effect is.

    • Effect of Abrasive Mixing on Polishing Effect of Through Silicon Via Copper Film
      ZHENG Qingping; WANG Ru; WU Tongxi

      Abstract:The particle size distribution of abrasives has a serious impact on the polishing effect of copper film.In the polishing process of abrasives with a single particle size,it is difficult to accurately evaluate the effect of some large or small abrasives.To solve this problem,different abrasive mixtures with similar particle sizes (40 nm,60 nm and 80 nm) were used to characterize the effect of particle size dispersion on copper film polishing.The effect of polishing liquid mixed with single abrasive,2 and 3 abrasive sizes on the polishing of silicon through hole copper film was studied.The results show that the polishing rate and surface quality of copper film can be improved by mixing abrasive with different particle sizes at the same mass fraction.When two kinds of abrasives are mixed,the larger the particle size difference,the faster the polishing speed.The polishing rate and polishing surface quality of abrasives mixed with three particle sizes are better than that of single particle size and two particle sizes.When the ratio of 40 nm,60 nm and 80 nm abrasives is 1∶3∶2,the polishing effect is the best.The physical model of abrasive distribution between copper sheet and polishing pad was established,the mechanism of increasing the removal rate of copper film with mixed abrasive was revealed,and the contact area between abrasive and copper sheet was calculated.

    • Effect of Slope Angle on Performance of Annular Stepped Seal in Aeroengine
      LI Qingan; WANG Jianbin; XU Huimin; YANG Liu; YANG Jianfei; YAO Jinjie

      Abstract:In order to optimize the structural properties of ring stepped materials in aeroengine,reduce the stress and deformation of seals under load,and improve the service life of seals,the model of annular stepped seal was established,the change of strain and stress of the seals was studied by applying load and changing the slope angle between the outer annular surface and the axial direction.The influence of slope angle on the service life of seals was discussed.The results show that the stress of the annular stepped seal under the external load is mainly generated at the concave angle of the first layer.Under the same load,the stress and deformation of the annular stepped seal firstly appear a maximum with the increase of the slope angle,and then fluctuate with similar amplitude.The service life is affected by the coupling effect of stress and deformation,and its variation law also shows a similar trend with the increase of slope angle,but the amplitude after the extreme value is greater than that of the stress and deformation.In the design process of annular stepped seal,optimizing the slope angle between the outer annular surface and the axial direction can reduce the stress and overall deformation of the seal to a certain extent,so as to indirectly prolong the service life of the seal.

    • Research on Sensitivity of Extreme-pressure and Anti-wear Additives in GTL Base Oil
      LIANG Xuemei; PENG Yiwen; YAN Yinan; PENG Chaolin; ZHENG Shudan; LI Yangyang; LI Yan

      Abstract:In order to investagate the sensitivity of GTL base oil and common extreme pressure antiwear agents,the additives of Zinc dialkyldithiophosphate (T203),tricresoll phosphate (T306),molybdenum dialkyldithiocarbamate (S-525),molybdenum amine complex (MOLYVAN 855),thiophosphate complex (T307),isobutene sulfide (T321) and synthetic ester (VANLUBE 7723) were mixed with GTL base oil respectively,and the maximum non-seizure load,wear scar diameter and friction coefficient of oil samples after single additive and compound additives were investigated by four-ball test rig.The results show that T307 and MOLYVAN 855 have the best extreme-pressure and anti-wear properties in GTL base oils.The combination of T203 and VANLUBE 7723 and T203 and MOLYVAN 855 significantly improves the extreme-pressure and anti-wear properties of GTL base oil,while the combination of T203 and S-525 has the best friction reduction effect.When T306 blends with S-525,T307 and T321 respectively,the extreme-pressure performance is similar.While the blending of T306 and T307 show good extreme pressure performance and good friction reduction and anti-wear effect.

    • Sealing Characteristics of Underwater Wellhead Connector under Thermodynamic Coupling
      LIU Tongliang; WEI Xingchao; FENG Ding

      Abstract:In order to study the sealing performance of the sealing gasket in the wellhead connector under the complex conditions of high temperature and high pressure on the seabed,the heat transfer model and thermodynamic coupling mathematical model were established according to the heat transfer theory,and the temperature field finite element model of the wellhead connector was established by using ANSYS software.Based on the numerical simulation of temperature field,the steady state and transient thermal structure coupling numerical simulation analysis was carried out to obtain the influence of oil and gas medium pressure and temperature on the sealing performance of wellhead connector.The results show that the higher the temperature of oil and gas medium,the greater the temperature gradient inside the sealing gasket.The temperature difference fluctuation between the parts of the connector and the sealing gasket under the influence of temperature impact is greater than that under constant and instantaneous temperature change.Through the steady-state thermal-structural coupling analysis,it is found that the metal sealing gasket has expansion deformation due to the temperature change,and the deformation is larger than that when no temperature load is applied,which indicates that the temperature load will directly affect the sealing performances of the connector in certain conditions.Through the transient thermal-structure coupling analysis,it is found that the rapid change of temperature in oil and gas medium leads to a larger linear expansion of the contact surface in the sealing gasket than that of the outer gasket,which leads to the discordant deformation inside the sealing gasket.Therefore,excessive temperature rise should be avoided in the actual working environment.

    • Solving Method of Volumetric Efficiency of Oil Production Single Progressive Cavity Pump Based on Fluid-structure Interaction
      WEI Yufen*; ZHAO Fengde; HAN Guoyou; ZU Haiying

      Abstract:Volumetric efficiency is an important technical index for the lifting performance of an oil production single progressive cavity pump(PCP).It is the most used method to obtain the volumetric efficiency by test.In order to improve the design efficiency and reduce the design cost of screw pump,a numerical simulation method of unidirectional fluid-structure interaction was proposed to solve the leakage and calculate the volumetric efficiency.According to the assembly relationship between stator and rotor,the geometric model was established,the stator rubber deformation at the sealing belt under different pressure difference was calculated,and the variation law of deformation with pressure difference was obtained.Taking the field test conditions as the simulation basis,the unidirectional fluid-structure interaction method was used to solve the leakage of PCP under the conditions of test speed and pump pressure,and its volumetric efficiency was further obtained.The simulation results are consistent with the field test results,which verified the effectiveness of using the numerical simulation method of unidirectional fluid-structure interaction to calculate the volumetric efficiency.Through this simulation analysis method,the structural parameters of a PCP can be optimized under the condition of reducing the amount of test,and the operation parameters can be provided.

    • Data Acquisition and Transmission Method of Oil Analysis Instrument Based on 2D Code
      LIU Jie; CHANG Xingshan; SUN Feng; SHI Hao; ZHOU Jianhui

      Abstract:Oil analysis instrument data acquisition and transmission is one of the important links in oil monitoring and analysis.At present,there are more and more oil analysis instruments and equipment with their own analysis software,but there are generally inconsistent information transfer interfaces,only export and transmission of current analysis oil sample data,inability to extract and transmit historical data content and non-analysis result files content,and no encryption information transmission function.Aimed at those problems,a set of integrated oil analysis instrument data acquisition and transmission solutions were proposed.This method can obtain the information source to be transmitted through the operating system API function and Hook technology,can obtain the required information through the integrated data format analysis algorithm,and then can obtain the information by scanning the 2D code at the receiving end and restore in the reverse by presenting and segmenting the data information by the 2D code.At the same time,the platform-based development concept was applied in this method to realize the universal processing of the instrument-side software and the receiving-side software,and integrate the data encryption and decryption functions.The application in the instruments such as spectral analysis and wear particle analysis instruments shows that this method realizes the collection and transmission of information such as spectral data and wear particle analysis images,and achieves good engineering effect.The design and application of this method provide a new solution for data acquisition and safe transmission of oil analysis instruments.

    • Effect of Coating Material on Roller Bearings Lubricating Performance
      WANG Zhijian; DONG Yuwei; ZHANG Xuefei

      Abstract:Coatings are widely used in roller bearings to enhance interface performance and improve fatigue life.In order to study the effect of coatings material properties on the lubrication performance of the roller bearings,the finite length line contact elastohydrodynamic lubrication model incorporating with coating properties was established.The influence of the coating material properties and coating thickness on lubricant film pressure and film thickness were investigated.The results show that as the coating thickness increases,the minimum film thickness for the stiff coating initially increases then decreases,while the minimum film thickness for the soft coating initially decreases then increases at light loads,and always decreases at heavy load.As the velocity increases,the pressure spike at the exit region increases,especially for the stiff coating.And the film thickness also increases,the flat region of the film decreases,the local reduction of the film thickness at the exit region increases.In order to improve the lubrication performance,when using a thicker soft coating,the crown value of the roller should be increased.However,when using a thicker stiff coating,the crown value of the roller should be reduced.

    • Research Progress on the Application of Corrosion Inhibitors in Copper Interconnection CMP Process
      YAN Han; NIU Xinhuan; ZHANG Yinchan; ZHU Yebo; HOU Ziyang; QU Minghui; LUO Fu

      Abstract:The slurry is one of the key elements of copper interconnection chemical mechanical polishing (CMP),each component plays different functions in the CMP process,while the selection and performance of corrosion inhibitor directly affect the post-polishing surface quality.The research progress of various types of corrosion inhibitors in copper interconnection CMP and the synergy between corrosion inhibitors and different types of additives in recent years was reviewed,the mechanism of action between corrosion inhibitors and different types of additives was introduced.The future prospects for the application of corrosion inhibitors in copper interconnection CMP were presented.It is pointed out that the development of green and environment-friendly CMP inhibitor for copper interconnection,the improvement of polishing quality through the synergistic effect of inhibitor compounding,and the further revelation of the mechanism of inhibitor from the microscopic perspective are the future research directions.

    • Research Progress of Mechanical Behaviour of Particles in Frictional Interfaces
      WANG Jihan; MU Hongxiang; LIU Tianxia; TANG Zhanqi

      Abstract:The solid particles entrained in the frictional interfaces will affect the friction and wear performance of contacting elements,and may lead to abnormal vibration and temperature rising.The application of surface texture can improve the tribological performance,and provide an effective way for friction reduction and wear resistance.The friction and wear mechanism of contacting interfaces which invaded by solid debris were introduced,and the mechanical model of the particle-friction pairs,the mechanical behaviour of the particles before and after entrapment,as well as the roles of surface texture when debris in the frictional interfaces were summarized.The research directions of particle-friction pairs are as follows:the research of mechanical behaviour of non-spherical particles,the research of migration law of particles,the research of mutual promotion and suppression relationship among the elements in the tribology system,and the research of mechanical behaviour of particles under grease lubrication conditions.

    • Performance Analysis of Different Seal Structures in Underwater Environment
      SONG Qiang; ZHANG Hao; XU Ke; YAO Chenjiao; ZHAO Feihu

      Abstract:In order to select a reasonable sealing structure of underwater equipment,the sealing performances of Glyd-ring,O-ring,X-ring combination and rectangular-ring in underwater environment were analyzed.The finite element analysis models of four sealing structures were established by ABAQUS.The change of equivalent stress,contact stress and shear stress of four sealing structures under pre-compression stage,variable compression rate and variable external pressure were studied,and the sealing performances of four sealing structures were compared and analyzed.The results show that under the same initial pre-compression rate,the maximum equivalent stress of the rectangular-ring is the largest,followed by X-ring combination,Glyd-ring and O-ring,and the maximum contact stress and maximum shear stress of rectangular-ring is the largest,followed by X-ring combination,O-ring and Glyd-ring.The rectangular-ring shows better sealing performance in the initial pre-compression stage.With the increase of initial pre-compression rate and external pressure,the maximum equivalent stress,contact stress and shear stress of Glyd-ring,O-ring,X-ring combination and rectangular-ring increase,and the stress growth rate of rectangular-ring and X-ring combination is much higher.The rectangular-ring and X-ring is better in sealing capacity,but its equivalent stress and shear stress are too high,which is easy to induce sealing failure.Although the sealing capacity of Glyd-ring and O-ring is not as good as that of rectangular-ring and X-ring combination,their maximum equivalent stress and shear force are small,so their service life is longer when used as seals.

    • Study on Matching Performance of Different Piston Pin Hole Bushing-Piston Pin Friction Pair
      LIU Xukang; ZHANG Limin; WANG Yanrong; DIAO Zhanying; WANG Genquan; WANG Haoyu; QIANG Hui; YUAN Xiaoshuai; KE Qinghang

      Abstract:The piston pin bore bushing-piston pin is one of the important frictional components of diesel engine,and its matching performance directly affects the service life and power characteristics.In order to investigate the matching performance of the piston pin hole bushings with different manufacturing processes with piston pin in use in diesel engines,the piston pin hole bushings prepared by extrusion and spinning processes and the imported bushing were matched with the piston pin in use in diesel engines,the load-bearing,anti-seize and wear resistance tests were carried out in the oscillating friction test bench.The test results show that the preparation process has a certain influence on the matching performance of the friction fairs.From the four aspects of friction torque,friction temperature,macroscopic morphology and wear amount,the extruded bushing has better bearing limit,anti-seize performance and wear resistance than the spinning bushing under the same working conditions,and can be used in place of imported bushings,which can provide reference for the matching of domestic piston pin hole bushings.

    • Failure Analysis and Improvement Measures of Grease-lubricated Bearing Used in Aeromotor
      CHEN Bin; XU Jun; ZHANG Jian; GUO Shuai; JIANG Yanhong

      Abstract:Aimed at the failure problem of grease-lubricated bearing used in aeromotor during the test,the reasons of the bearing damage were analyzed from five aspects,including the appearance,material,hardness,microstructure and grease.It is found that the main reason for the bearing failure is that the wear debris generated by the wear of the seal ring falls into the bearing and cause the deterioration of the grease.The improvement measures such as changing the sealing ring material from polytetrafluoroethylene to fluororubber with lower hardness and reducing the interference between the contact lip of the sealing ring and the inner ring flange are proposed,and good results are achieved.

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