Investigations On Fluid-structure Interaction Of Flow-induced Vibration Of Low Specific Speed Centrifugal Pumps

Low-specific-speed centrifugal pumps with high head and small flow characteristics play an important role in the fields of aviation, chemical industry. Because of the high head, the vibration of the centrifugal pump often occurs during the pump running, which will damage the whole pump system. The unsteady fluid force in the centrifugal pump is the main source which induces the vibration. Therefore, it is necessary to study the vibration induced by fluid force in t centrifugal pumps. In this paper, steady and unsteady numerical simulation for pump has been conducted based on N-S equations and SST k-ω turbulence model, the static structure and modal analysis of rotor system is carried out by the one-way fluid structure interaction method,at the same time the experimental research on the external characteristics and vibration of the model pump is carried out. The main research contents are contained as follows:(1)The Pro/E software was used to generate computational geometries. ICEM-CFD was used to generate meshes. The 3-D viscous unsteady flows in pump model were solved using commercial CFD software CFX.(2)Based on the N-S equations and the SST k-ω turbulence model, the flow fields of model pump were numerically simulated with both steady and unsteady methods, and based on the analysis of the unsteady simulation results, the pressure fluctuations near the volute tongue and the radial force working on volute wall and impeller were analyzed in detail.(3)According to the results of single-phase fluid solid coupling, the static mechanical analysis of centrifugal pump rotor was accomplished. On the condition of take no account of the effect of damping and inertia, the stress, strain and displacement of impeller which caused by the fluid force were calculated. The modal analysis of centrifugal pump rotor structure was carried out and the vibration characteristics were analyzed. The pressure fluctuation of tongue volute was closed with the relative position between blade and tongue volute, the static pressure near the tongue volute reached the maximum when the blade sweep tongue volute,the radial force pressed on the volute and blade was greatly influenced by the flow rate.(4)The performance curves(H-Q and η-Q) of model pump were acquired through the experiment. Based on the vibration test, the vibration characteristics of pump were analyzed and also made compare with that of the simulation results.