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This paper takes a marine steam turbine control valve as the research object, studies the vibration response under pressure pulse excitation. First, the transient flow field analysis is made to obtain the time-domain information of the pressure pulsation; Followed by pressure pulsations fast Fourier transform into the frequency domain information, access to the load spectrum; Then modal analysis is studied to obtain the natural frequencies and mode shapes; Finally, based on the analysis of vibration modes, research vibration response and resonance problems of control valve. The study found that the vibration of control valve is strongly in low frequency excitation, but high-frequency excitation makes relatively little impacts on it; The diffuser and downstream of valve is the main area of generating vibration. Supported by the Fundamental Research Funds for the Central Universities (HEUCF140707).

The instability flow in the control valve often lead to abnormal vibration, the valve wear and the valve stem destruction, also lead to pressure loss. The flow in the control valve show complex flow regime distribution and variation, it is a typical unsteady flow. Therefore, it is necessary to theoretical calculation and qualitative analyses the flow field of valve by the numerical simulation method. In this paper, we study on the axial force of valve stem that caused by the fluid pulsation pressure. Establishing the flow field model of the control valve, generating the computational grid through the pre-processor, using the CFD software to do discretized and solved, getting visualization graphics of the internal flow field. Study the changes of the flow characteristics according to different pressure ratio, getting the variation characteristic of axial force. Provide the basis for subsequent optimization and design of the low vibration control valve.