Study On Characteristics And Suppression Measures Of Vibration Induced By Flow Of Turbine With Partial Admission

Enhances the supercritical pressure is an important way to improvethe thermal efficiency of the steam turbine. The enhancement of steamparameters of turbine can cause flow-excited vibration. Thelow-frequency vibration of high pressure rotor of large sized steamturbine is mainly caused by flow-excited vibration. It directly threatensthe safe operation of turbine, Seriously affects the adaptability of unitload and becomes one of the prominent problems that are encountered inthe process of developing turbine with high parameter and large capacity.As the domestic turbine with supercritical pressure is developing, thiskind of issue of low-frequency vibration will also be faced. Therefore,strengthening the research on the low-frequency vibration caused by flowexcitation of steam turbine is very necessary.This paper firstly analyzes the producing mechanism of flow-excitedvibration of turbine and the hazards of flow-excited vibration, studies and confirms the distribution of the signal of flow-excited vibration in thefrequency domain and provides the theory basis for the later empiricaldatum analysis.Through the analysis of flow stress on blade of control stage, thispaper proposes that the thought of symmetrical admission is an effectiveaction to reduce the intensity of flow-excited vibration, and verifies thisthought by experimental research. Based on the analysis and experimentalresearch, this paper proposes four optimization means to reduce theflow-excited vibration.Because the flow exciting force on rotor blade has a directrelationship with the angle of guide vane, this paper also analyzes theinfluence of the change of the angle of guide vane to the flow excitingforce on rotor blade in theory and experiment. This paper finds that theflow-excited vibration is reduced and power of the output of steamturbine is increased when the guide vane angle reduces from+6°to-6°.This paper also studies the effect of unbalanced force on the lowfrequency vibration of the bearing. Because the flow-excited vibrationeasily causes bearing jitter even to have problems，this paper finallyconducts a study on fault diagnosis technology of bearing based onvibration and sound signals. And finds that using the sound sensor tocollect sound signal in the terminal of copper pipe which is used forsimulating listening stick has very good effect in the fault diagnosis...