In this paper,the formulas of elasto-hydrodynamic traction coefficients of three Chinese aviation lubricating oils,4109,4106 and 4050,were obtained by a great number of elastohydrodynamic traction tests.The nonlinear ...In this paper,the formulas of elasto-hydrodynamic traction coefficients of three Chinese aviation lubricating oils,4109,4106 and 4050,were obtained by a great number of elastohydrodynamic traction tests.The nonlinear dynamics differential equations of high-speed angular contact ball bearing were built on the basis of dynamic theory of rolling bearings and solved by Gear Stiff（GSTIFF） integer algorithm with variable step.The impact of lubricant traction coefficient on cage＇s dynamic characteristics in high-speed angular contact ball bearing was investigated,and Poincare map was used to analyze the impact of three types of aviation lubricating oils on the dynamic response of cage＇s mass center.And then,the period of dynamic response of cage＇s mass center and the slip ratio of cage were used to assess the stability of cage under various working conditions.The results of this paper provide the theoretical basis for the selection and application of aviation lubricating oil.展开更多
The lubrication design and heat transfer determination of bearing chambers in aeroengine require a sufficient understanding of the oil droplet-film interaction and physical characteristic in an oil/air two-phase flow ...The lubrication design and heat transfer determination of bearing chambers in aeroengine require a sufficient understanding of the oil droplet-film interaction and physical characteristic in an oil/air two-phase flow state. The analyses of oil droplet movement, mass and momentum transfer during the impingement of droplet/wall, as well as wall oil film thickness and flow velocity are very important for the bearing chamber lubrication and heat transfer calculation. An integrated model in combination with droplet movement, droplet/wall impact and film flow analysis is put forward initially based on the consideration of droplet size distribution. The model makes a contribution to provide more practical and feasible technical approach, which is not only for the study of droplet-film interaction and physical behavior in bearing chambers with oil/air two-phase flow phenomena, but also useful for an insight into the essence of physical course through droplet movement and deposition, film formation and flow. The influences of chamber geometries and operating conditions on droplet deposition mass and momentum transfer, and wall film thickness and velocity distribution are discussed. The feasibility of the method by theoretical analysis is also verified by the ex- isting experimental data. The current work is conducive to expose the physical behavior of wall oil film configuration and flow in bearing chamber, and also significant for bearing chamber lubrication and heat transfer study under oil/air two-phase flow conditions.展开更多
A seal device as an important component of aeroengines has decisive influence on per-formance,reliability,and working life of aeroengines.With the development of aeroengines,demands on the performance characteristics ...A seal device as an important component of aeroengines has decisive influence on per-formance,reliability,and working life of aeroengines.With the development of aeroengines,demands on the performance characteristics of seal devices are made strictly.Finger seal as a novel kind of sealing device,recently attracts more and more attentions in academic circles and engineer-ing fields at home and abroad.Research on finger seals has been extensively developed,especially on leakage and wear performances under dynamic conditions.However,it is a pity that the work on finger seals has been limited with a single approach that is improving the performance by structural optimization;in addition,the technology of dynamic analysis on finger seals is weak.Aiming at the problems mentioned above,a distributed mass equivalent dynamic model of finger seals considering the coupling effect of overlaid laminates is established in the present paper,the dynamic perfor-mance of 2.5 dimension C/C composite finger seal is analyzed with the model,and then the effects of fiber bundle density and fiber bundle preparation direction on finger seal's dynamic performance are discussed,as well as compared with those of Co-based alloy finger seal.The current work is about dynamic analysis of finger seals and application of C/C composite in this paper may have much academic significance and many engineering values for improving research level of finger seal dynamics and exploring feasibility of C/C composite being used for finger seals.展开更多
Abstract The traction characteristics of synthetic lubricants in rolling/sliding contacts arestudied in detail in the present paper by using thermal partial elastohydrodynamicIubrication theory and the Ree-Eyring rheo...Abstract The traction characteristics of synthetic lubricants in rolling/sliding contacts arestudied in detail in the present paper by using thermal partial elastohydrodynamicIubrication theory and the Ree-Eyring rheological model which accounts for thenon Newtonian behavior of the lubricant. Tbe variety regularities of the tractioncoefficient of synthetic lubricants with the load, rolling speed and lubricant vtscosity arcobtained,and a comparison between the calculated results presented in the paper and tbeexperimental results of Gupta et al is also shown.In addition,a working formula,whichfits the traction coefficient of syntbetic lubricant versus slide-roll ratio curve,has alsobeen devised.展开更多
基金financially co-supported by the National Natural Science Foundation of China(No.U1404514)Henan Outstanding Person Foundation(No.144200510020) of ChinaCollaborative Innovation Center of Major Machine Manufacturing in Liaoning,China
文摘In this paper,the formulas of elasto-hydrodynamic traction coefficients of three Chinese aviation lubricating oils,4109,4106 and 4050,were obtained by a great number of elastohydrodynamic traction tests.The nonlinear dynamics differential equations of high-speed angular contact ball bearing were built on the basis of dynamic theory of rolling bearings and solved by Gear Stiff（GSTIFF） integer algorithm with variable step.The impact of lubricant traction coefficient on cage＇s dynamic characteristics in high-speed angular contact ball bearing was investigated,and Poincare map was used to analyze the impact of three types of aviation lubricating oils on the dynamic response of cage＇s mass center.And then,the period of dynamic response of cage＇s mass center and the slip ratio of cage were used to assess the stability of cage under various working conditions.The results of this paper provide the theoretical basis for the selection and application of aviation lubricating oil.
基金National Natural Science Foundation of China (50975233)
文摘The lubrication design and heat transfer determination of bearing chambers in aeroengine require a sufficient understanding of the oil droplet-film interaction and physical characteristic in an oil/air two-phase flow state. The analyses of oil droplet movement, mass and momentum transfer during the impingement of droplet/wall, as well as wall oil film thickness and flow velocity are very important for the bearing chamber lubrication and heat transfer calculation. An integrated model in combination with droplet movement, droplet/wall impact and film flow analysis is put forward initially based on the consideration of droplet size distribution. The model makes a contribution to provide more practical and feasible technical approach, which is not only for the study of droplet-film interaction and physical behavior in bearing chambers with oil/air two-phase flow phenomena, but also useful for an insight into the essence of physical course through droplet movement and deposition, film formation and flow. The influences of chamber geometries and operating conditions on droplet deposition mass and momentum transfer, and wall film thickness and velocity distribution are discussed. The feasibility of the method by theoretical analysis is also verified by the ex- isting experimental data. The current work is conducive to expose the physical behavior of wall oil film configuration and flow in bearing chamber, and also significant for bearing chamber lubrication and heat transfer study under oil/air two-phase flow conditions.
基金supported by the National Natural Science Foundation of China(No.50575182)the Natural Science Foundation of Shaanxi Province of China(2014JM7266)
文摘A seal device as an important component of aeroengines has decisive influence on per-formance,reliability,and working life of aeroengines.With the development of aeroengines,demands on the performance characteristics of seal devices are made strictly.Finger seal as a novel kind of sealing device,recently attracts more and more attentions in academic circles and engineer-ing fields at home and abroad.Research on finger seals has been extensively developed,especially on leakage and wear performances under dynamic conditions.However,it is a pity that the work on finger seals has been limited with a single approach that is improving the performance by structural optimization;in addition,the technology of dynamic analysis on finger seals is weak.Aiming at the problems mentioned above,a distributed mass equivalent dynamic model of finger seals considering the coupling effect of overlaid laminates is established in the present paper,the dynamic perfor-mance of 2.5 dimension C/C composite finger seal is analyzed with the model,and then the effects of fiber bundle density and fiber bundle preparation direction on finger seal's dynamic performance are discussed,as well as compared with those of Co-based alloy finger seal.The current work is about dynamic analysis of finger seals and application of C/C composite in this paper may have much academic significance and many engineering values for improving research level of finger seal dynamics and exploring feasibility of C/C composite being used for finger seals.
文摘Abstract The traction characteristics of synthetic lubricants in rolling/sliding contacts arestudied in detail in the present paper by using thermal partial elastohydrodynamicIubrication theory and the Ree-Eyring rheological model which accounts for thenon Newtonian behavior of the lubricant. Tbe variety regularities of the tractioncoefficient of synthetic lubricants with the load, rolling speed and lubricant vtscosity arcobtained,and a comparison between the calculated results presented in the paper and tbeexperimental results of Gupta et al is also shown.In addition,a working formula,whichfits the traction coefficient of syntbetic lubricant versus slide-roll ratio curve,has alsobeen devised.
