Research On Flow-induced Vibration Of Rampressor Rotor System

The core part of this Advanced Supersonic Component Engine(ASCE) is Rampressor rotor. Aspects of the aerodynamic design of a unique supersonic high pressure ratio compressor rotor, termed the Rampressor, are presented. Rampressor rotor has several significant advantages such as high speed, high shock compression efficiency, small volume, light weight, and low cost of production and maintenance, but many key technical problems to its research are also brought, such as structure design of Rampressor rotor and its inlet, flow loss of the inlet, starting problem, flow induced vibration coupled with Rampressor rotor and its inlet, and dynamic stability of Rampressor rotor system, etc. Taking Rampressor rotor system as research object in this paper, flow model of supersonic inlet on Rampressor rotor and dynamics model of Rampressor rotor-bearing system are established. Flow characteristics and incentive features of supersonic inlet on Rampressor rotor are studied. Based on fluid-structure coupling method, coupling vibration between Rampressor rotor and supersonic flow of its inlet and stability of rotor-bearing system are analyzed. Dynamic characteristics and stability of Rampressor rotor-bearing system has been verified by the corresponding experimental study. The above works have great importance for design of Rampressor rotor inlet and rotor-bearing system, and vibration reduction of Ragmen engine.In the light of shock compression loss in Rampressor inlet design, three kinds of design schemes for binary supersonic inlet with internal compression type are proposed. The inlet performance of three schemes and the advantage and disadvantage of its design, are compared and analyzed. And then design of Rampressor rotor inlet is completed, and supersonic flow model of Rampressor rotor inlet is established, which is considered with effect of High speed spinning Coriolis force. The design feasibility of Rampressor rotor inlet is verified by flow analysis of Rampressor rotor inlet under ideal non-viscous fluid. The supersonic flow model of Rampressor rotor inlet has established is provided the basis for research on flow and incentive characteristics of Rampressor rotor inlet.Supersonic flow model of Rampressor rotor inlet with bleed system is established, which is considered with viscous flow and effect of high speed spinning Coriolis force. Flow control technologies including inlet boundary layer bleeding are studied for Rampressor rotor inlet. Based on these, effect of rotor whirl on starting ability and flow performance, and flow excitation characteristics of Rampressor inlet under back pressure pulsation are analyzed. The study found that it can be to ensure great flow performance and stability of inlet by choosing reasonable bleed scheme or controlling whirling amplitude of Rampressor rotor, the size of pulsation frequency and amplitude for inlet back pressure.Mutual coupling between Rampressor rotor whirl and its inlet flow is coupling problem between fluid mechanics and rotor dynamics. In allusion to this problem, a fluid induced coupling algorithm for Rampressor rotor is proposed based on Navier-Stokes flow equations and Timoshenko beam element model. Using this algorithm, effects of different time scales and coupling data exchange mode on vibration characteristics of rotor-bearing system, and coupling vibration characteristics of Rampressor rotor considering flow induced under different incentive are analyzed. Based on these, flow induced vibration analysis platform of Rampressor rotor is established on basis of fluid induced coupling algorithm has been proposed. Fluid induced coupling algorithm and vibration analysis platform can be used for design of Rampressor rotor system, and analysis of vibration and stability.On the basis of research on coupled flow induced vibration characteristics of Rampressor rotor, effects of air exciting force, gas bearing structural parameters and combustor pressure pulsation on vibration characteristics and stability of Rampressor rotor-gas bearing system are analyzed by fluid induced coupling algorithm proposed in this study. Research indicate that if Rampressor rotor is supported by gas bearing, it can be used to achieve the effective control for Rampressor rotor vibration, and improve the stability of the system by improving the supply pressure of gas bearing or reducing the bearing clearance of gas bearing or controlling size of combustor pressure pulsation amplitude.Based on design method for Rampressor rotor inlet and research on modeling for Rampressor rotor-bearing system, test bed of Rampressor rotor compression system is finally established, which can realize to adjust inlet compression profile and guide vane, and control tip clearance. And inherent frequency for Rampressor rotor, critical speed and performance for Rampressor rotor-bearing system are verified, which provide the experimental basis for the subsequent optimization of the performance, rotor-bearing system and whole machine design, etc.