Study into the Improvement of Dynamic Stress Characteristics and Prototype Test of an Impeller Blade of an Axial-Flow Pump Based on Bidirectional Fluid–Structure Interaction

Abstract

This paper performed a numerical study into the dynamic stress improvement of an axial-flow pump and validated the simulation results with a prototype test. To further analyze the dynamic stress characteristics of impeller blades of axial-flow pumps, a bidirectional fluid–structure interaction (FSI) was applied to numerical simulations of the unsteady three-dimensional (3-D) flow field of the whole flow system of an axial-flow pump, and the gravity effect was also taken into account. In addition, real-structure-based single-blade finite element model was established. By using the finite element method, a calculation of the blade’s dynamic characteristics was conducted, and its dynamic stress distribution was determined based on the fourth strength theory. The numerical results were consistent with the prototype tests. In a rotation cycle, the dynamic stress of the blade showed a tendency of first increasing, and then decreasing, where the maximum value appeared in the third quadrant and the minimum appeared in the first quadrant in view of the gravity effect. A method for reducing the stress concentration near the root of impeller blades was presented, which would effectively alleviate the possibility of cracking in the unreliable region of blades. Simultaneously, an experimental method for the underwater measurement of the dynamic stress of prototypical hydraulic machinery was put forward, which could realize the underwater sealing of data acquisition instruments on rotating machinery and the offline collection of measured data, finally effectively measuring the stress of underwater moving objects.

Study on hydraulic characteristics of large vertical axial-flow pump used as constant frequency power generation

“…The finite element static stress calculation needs to impose sufficient constraints to restrain the movement of the structure and prevent the rigid displacement of the structure. 26 Because the cylindrical surface contacting the hub of the blade can only prevent the radial and axial movement of the blade, while the tangential direction can rotate, the cylindrical surface here is constrained by cylindrical constraints to restrict the radial and axial movement of the surface. The interface of fluid–solid coupling is the whole blade part.…”

Numerical Simulation of Transient Characteristics of Start-Up Transition Process of Large Vertical Siphon Axial Flow Pump Station

“…The flow inside the pump device is regarded as three-dimensional incompressible nonviscous turbulence. The control equation of numerical calculation is as (Shi et al, 2017;Chen et al, 2018;Kan et al, 2019):…”

Influence of Blade Angle Deviation on the Hydraulic Performance and Structural Characteristics of S-Type Front Shaft Extension Tubular Pump Device

“…Zhang et al [23] performed FSI calculations for a certain type of axial-flow pump, and the research shows that the natural frequency of the impeller is significantly reduced by the water medium, while the effect of prestress on the modal is not obvious. Kan et al [24,25] revealed the dynamic stress change law of the blade during the impeller design stage based on the FSI method and proposed that thickening the blade root can significantly improve the stress distribution of the blade and improve the safety and stability of the blade.…”