Parametric Design Research On Combined Compressor Vibration

With the advantages of both the axial and centrifugal compressor, the combined compressors arewidely used in the middle and small size aero-engines. Compact structure and high rotation speed arethe obvious features of the middle and small size aero-engine, which make a great challenge to thedynamic characteristic of the whole engine. As a key component, the dynamic characteristic of thecombined compressor impacts the dynamic characteristic of the whole engine directly. For thecombined compressor, the research covers the following contents.1. The geometry variable parameters were selected. Then the combined compressor modelingparametric system was established, which was based on VB language and UG NX Open API language.Utilizing this system, the parameteric modeling could be realized rapidly.2. The transfer matrix analysis and the finite element analysis were performed on the samecombined compressor model. The accuracy of the finite element model was validated.3. The modal analysis was performed on the rotor model, the stator model and the wholecomponent model respectively. The various calculation results were compared and analyzed. At last,the dynamic stiffness of the bearing-casing system was calculated.4. The dynamic characteristic of the combined compressor was analyzed by the static stiffness,dynamic stiffness and the whole compressor component model respectively. The various calculationresults were compared and analyzed. The unbalance response analysis was performed on the wholecompressor component system. The different parameter of the combined compressor models wasadopted to analyze the dynamic character of the combined compressor. By studying the sensitivity ofthe critical speed to the selected parameters, the effect of the selected parameters to the dynamiccharacteristic of the combined compressor was analyzed.The conclusion of this thesis is helpful to the rescarch of combined compressor design and thewhole aero-engine. The critical speed can be changed by adjusting the geometry parameters suitably,which has significance in engineering applications.