Current studies on the operation of the axial pump mainly focus on hydraulic performances, while the coupled interaction between the fluid and structure attracts little attention. This study aims to provide numerical investigation into the vibration features in a vertical axial pump based on two-way iterative fluid–structure interaction method. Three-dimensional coupling model was established with high-quality structured grids of ADINA software. Turbulent flow features were studied under design condition, using shear–stress transport k-ω turbulence model and sliding mesh approach. Typical measure points along and perpendicular to flow direction in fluid domain were selected to analyze pressure pulsation features of the impeller and fixed guide vane. By contrast, vibration features of equivalent stress in corresponding structural positions were investigated and compared based on fluid–structure interaction method. In order to explore fluid–structure interaction vibration mechanism, distribution of main frequencies and amplitudes of the measure points was presented based on the Fast Fourier Transformation method. The results reveal the time and frequency law of fluid pressure pulsation and structural vibration at the same position in the vertical axial pump while additionally provide important theoretical guidance for optimization design and safe operation of the vertical axial pump.

Flow condition was simulated in a shaft tubular pump by using the Shear-Stress Transport (SST) k-ω turbulence model with high quality structured grids in design condition. Corresponding structural vibration characteristics were then analyzed based on two-way coupled Fluid-Structure Interaction (FSI) method. Fluid results showed that flow in the outlet flow passage was a combination of the axial flow and circumferential rotation motion. Time and frequency domain analysis of pressure pulsation of typical measure points indicated that larger pulsation amplitudes appeared in the tip of the blades and the main vibration source was the pressure pulsation induced by rotation of the blades. The fluid pulsation amplitudes decreased gradually along the flow direction, which can be ascribed to the function of fixed guide vane. Structural analysis of the blades in both pressure and suction side indicated that significant stress concentration was formed at the blade and hub connection near the leading edge. Maximum effective stress of the blades varied periodically, so prevention measures of the fatigue of blades should be taken. This research can provide important reference for the design of the tubular pump.

It is of significant value to understand the unsteady hydraulic features and pressure pulsation transmission path in the flow channel through a turbine for providing technical support for turbine design and optimization, as well as laying a foundation for analysis of the stability and the coupled vibration of the hydropower house. In this paper, a three-dimensional mechanics–hydraulics–concrete structure coupled numerical model was established to accurately simulate Francis hydraulic machinery, including the high-rotating turbine runner and fixed guide vane, the unsteady flowing water, the structure of the entire flow channel, as well as the dynamic interaction between them. Turbulent hydraulic features of flow condition and pressure pulsation in design operation were explored using the detached eddy simulation (DES) turbulence model. Then, a novel method was proposed to identify the fluid pressure pulsation transmission path based on the time-delayed transfer entropy method and wavelet theory. On basis of time and frequency analysis of pressure calculation results, investigation into identification of pressure pulsation transmission path was performed using the method of traditional transfer entropy and the method adopted in this paper. The pressure pulsation transmission features in the entire flow channel were revealed during operation of the large-scale Francis turbine. The research method and results could not only lay a basis for exploring the structural vibration regularity of the hydropower house but also provide a scientific reference for vibration reduction design of the hydropower house.

The working principle of a large hydropower station is to guide the high-pressure water flow to impact the turbine to rotate and generate electricity. The high-pressure water flow impacts the turbine blades, which forms complex high-speed eddy currents in the spiral case and the draft tube and causes complicated vortex-induced vibration problems. Traditionally used harmonic response methods and dynamic time-history analysis methods are difficult to reflect this complex fluid-solid dynamic coupling problem. In this paper, the bidirectional fluid-structure interaction (FSI) simulation analysis theory for a large hydropower house is studied, and the analysis methods of geometric simulation, mechanical simulation, and vibration energy transmission path simulation are presented. A large-scale 3D fluid-hydraulic machinery-concrete structure coupled model of a hydropower house is established to study the vortex-induced vibration mechanism and coupled vibration law during transient unit operation. A comparison of the fluid results against the in-site data shows good agreement. Structural responses of vibration displacement, velocity, and acceleration reveal coupled regularity of hydraulic machinery-concrete structure-fluid during blades rotating periods, and it comes to the conclusion that the turbine blade rotation is the main vibration source of the hydropower house. The research results can provide a scientific basis for the design and safe operation of the hydropower house.

This article aims to explore the vibration transmission path in the hydropower house using the time-delayed transfer entropy method. A three-dimensional fluid-concrete structure-hydraulic machinery coupling simulation model of the Xiangjiaba hydropower house was established, and the vibration acceleration and equivalent stress of the structure were calculated in the time domain based on the two-way iterative fluid-structure interaction method. The characteristic indexes of information transmission were quantitatively presented, including the rate of information transmission, transmission path contribution, to describe the vibration energy transmission paths and transmission characteristics of different vibration variables as well as different directions of the same variable in the hydropower house. The study indicates that the vertical acceleration can identify more abundant vibration transmission paths, and the lower bracket contributes most to the vibration transmission of the powerhouse. The research outcome can provide a scientific basis for structural optimization, vibration attenuation, and isolation design of the hydropower house.