Oil droplets can break up during flight and form many secondary droplets in an aero-engine bearing chamber due to aerodynamic drag forces. The motion properties of secondary droplets have significant influence on the two-phase oil/air flow phenomena in bearing chambers. In this work, oil droplet trajectories and velocities are developed by accounting for in-flight breakup. The droplet motion is modelled using a Lagrangian tracking method, and the trajectories and velocities are calculated by numerical integration of the oil particle momentum equation with forth-order Runge-Kutta scheme. The trajectories and velocities change abruptly at the breakup location, compared with unconsidering breakup. Subsequently, the effects of operating conditions on oil droplet motions are discussed. The numerical results show that the influence of breakup on oil droplet trajectory and velocity are considered necessarily when simulating two-phase oil/air flows in bearing chambers.

Most of the studies about tilting pad journal bearings are for load-on-pad or load-between-pad tilting pad journal bearings, and for the other loading forms, the performance are often estimated by the performance of the two limited conditions, that may reduce the reliablity of bearing design or lead to waste materials in design. To obtained the influence of the load directions on the static and dynamic characteristics of the tilting pad journal bearing, which is called eccentric load effect in this papers, the performance calculation of the tilting pad journal bearing in different load directions is operated with a self-designed program. The results show that the load directions have considerable effects both on the static and dynamic characteristics of the tilting pad journal bearing, for the operating condition that load direction changed rapidly, it need performance analysis of the bearing in its special loading forms to enhance the precision and efficiency of bearing design, espacially where the dynamic performance of the tilting pad journal bearing is demanding.

For the finger seal, leakage and wear are key factors to affect its sealing performance and service life. To reduce the wear of the finger seal, C/C composites are probably used for finger seal material preparation for its self-lubrication and light weight properties compared with the metal. The work to be presented here assessed the elastic properties of the 2.5D C/C composites by the volume average method and established a finite element model for finger seal dynamic analysis. The results show that increasing warp yarn density and using shallow direct-joint structure can notably improve sealing performance of the finger seal, but can also increase contact pressure between the finger seal and the rotor.

Carbon fiber epoxy resin composite and polyimide material are likely to be applied to pulley-guideway system of the new satellite antenna. Their tribological properties have effects on the motion characteristics of the pulley-guideway system. To master the tribological properties of carbon fiber epoxy resin composite and polyimide material, this paper carries out tests of tribological properties and wear behavior of carbon fiber epoxy resin composite and polyimide material at 130°C and 30°C. Carbon fiber epoxy resin composite is used as the grinding specimen and polyimide material is used as the counter-grinding specimen. Tribological properties of this material pairs is studied under diverse linear velocity and external loads. The results show that friction coefficient of this material pairs is stable under different conditions, especially at 30°C. Meanwhile, wear behavior of this material pairs is mainly affected by ploughing of surface roughness at low temperature, while by surface micro-spalling at high temperature.

A fundamental study has been performed to analysis the fluid dynamic characteristics of the gas medium in a rotating disk cavity through the commercial software CFX11.0. This paper aims to discuss the impact of the speed of rotating disk, axial and radial size and parietal lubricant film velocity and other factors on the gas flow state in cavity. Several conclusions have been obtained: the speed of rotating disk has a great impact on velocity distribution of gas flow field; the dimensionless tangential velocity of the gas medium decreases along the radial direction, and with the speed increasing, it shows a certain regularity; Dimensionless radial velocity decreases along the radial direction, and the speed of rotating disk nearly has no influence on this; The shear stress distribution along the radial direction and the distribution of tangential velocity have similar regularity; the impact of disk cavity height on the distribution of the tangential velocity along radial direction in the gas flow field is much more obvious than the impact of disk cavity width.