Dynamic Stress Prediction in Centrifugal Compressor Blades Using Fluid Structure Interaction

Abstract

A computational model is developed that predicts stresses in the blades of a centrifugal compressor. The blade vibrations are caused by the wakes coming off stationary inlet guide vanes upstream of the impeller, which create a periodic excitation on the impeller blades. When this excitation frequency matches the resonant frequency of the impeller blades, resonant vibration is experienced. This vibration leads to high cycle fatigue, which is a leading cause of blade failure in turbomachinery. Although much research has been performed on axial flow turbomachinery, little has been published for radial machines such as centrifugal compressors and radial inflow turbines. A time domain coupled fluid-structure computational model is developed. The model couples the codes unidirectionally, where pressures are transferred to the structural code during the transient solution, and the fluid mesh remains unaffected by the structural displacements. A Fourier analysis is performed of the resulting strains to predict both amplitude and frequency content. This modeling method was first applied to a compressor in a single stage centrifugal compressor test rig. The analysis results were then validated by experimental blade strain measurements from a rotating test. The model correlated very well with the experimental results. In this work, a model is developed for a liquefied natural gas (LNG) centrifugal compressor that experienced repeated blade failures. The model determined stress levels in the blades, which helped to predict the likely cause of failure. The method was also used to investigate design changes to improve the robustness of the impeller design.

Dynamic stress of impeller blade of shaft extension tubular pump device based on bidirectional fluid-structure interaction

“…In view of fluid-structure interaction effect, Langthjem et al [4] studied the flow-induced noise of a centrifugal pump. Nevertheless, few researches have focused on fluid-structure interaction [1][2][3][4][5][6][7] studying dynamic stress of tubular pump impeller structure. Furthermore, most research [5][6][7] selects the overall structure of the impeller as a finite element analysis model, which cannot accurately describe the actual pump impeller.…”

“…Nevertheless, few researches have focused on fluid-structure interaction [1][2][3][4][5][6][7] studying dynamic stress of tubular pump impeller structure. Furthermore, most research [5][6][7] selects the overall structure of the impeller as a finite element analysis model, which cannot accurately describe the actual pump impeller. By virtue of CFD software CFX and Ansys Workbench platform, we calculated bidirectional fluidstructure interaction on the impeller blade of a shaft extension tubular pump device, and obtained the numerical distribution of dynamic stress of the impeller blade under different lift conditions.…”

A Study on the Multi-Objective Optimization of Impeller for High-Power Centrifugal Compressor

“…For the structural safety assessment of a centrifugal compressor impeller, Lerche et al [1] analysed the maximum stress displacement and vibration characteristics when an impeller is subject to the influence of centrifugal force. Park et al [2] examined the effects of changes in the tip gap and impeller blade shape on aerodynamic performance and structural safety of an impeller through FSI analysis.…”

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

“…Additionally, multiple scholars have studied FSI problems by introducing the immersed boundary method (IBM), which could avoid the numerical instability induced by grid deformation due to FSI [7][8][9][10][11]. Among the current studies on FSI [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], few are related to the structural dynamic stress of axial-flow pump impellers, and the structural response to the transient fluid-structure interaction (FSI) of axial-flow pump impellers has not been studied in depth. Meanwhile, the overall structure of an impeller has been selected as the research object for finite element analysis in the majority of studies [13][14][15][16][17], which could not show the performance of a real pump impeller accurately.…”