Research On Hydrodynamic Characteristics Of Interlaced Bump Foil Gas Aerodynamic Bearing

As a new member of the sliding bearing,hydrodynamic bearings has been widely used and developed from the invention.And the bump foil bearing is a new type of gas aerodynamic bearing,with the structure of a fixed layer of foil to support at the bottom of the flat and a layer of foil above for elastic support.The bump foil bearing has the advantages of simple structure,good stability under high speed,clean and pollution-free,etc.Therefore,it has been widely researched domestic and abroad.Therefore,based on the traditional structure,it presents the layout of the interlaced bump foil structure.Through the correlation study of the changes brought by its new structure,it is easy to optimize the bearing so as to be better applied to the field of aeronautic.The principle of bump foil gas aerodynamic bearings will be first described.The theoretical modeling of interlaced bump foil structure is based on the first generation of bump foil bearings.Through the finite difference method and relaxation iteration method to solve the coupling of Reynolds equation and the film thickness equation,the basic pressure and thickness parameters are obtained by the relevant model to have the verification and a simple analysis.Then using the static characteristics of bearings have a comparative analysis.The advantages and disadvantages of interlaced bearings are further analyzed by studying the changes of static parameters such as pressure,thickness,bearing capacity and deflection angle under different conditions of speed and length-diameter ratio,as well as the comparison with the traditional bearings.During the comparison,it shows that the interlaced bearing has a high load capacity and friction torque.As for the dynamic characteristics,on the basis of the finite difference method and the relaxation iteration method,the perturbation method is introduced to solve the coupling of Reynolds equation with time item and the film thickness equation.And the dynamic characteristics parameters are calculated and verified by the basic pressure and thickness parameters.Between the comparison with conventional structural bearing,it shows that the direct terms of dynamic stiffness and dynamic damping of interlaced bearing is larger than conventional bearing,so interlaced bearing has good capacity of anti-disturbance and restore its former condition.Finally,based on the research of this kind of bearing,the relevant parameters of a small engine's bearings are introduced to study the changes brought by the conversion into foil bearing,so it can be able to relate the application of such bearings on this type of engine and optimization.