Reconstruction and Prediction of Flow Field Fluctuation Intensity and Flow-Induced Noise in Impeller Domain of Jet Centrifugal Pump Using Gappy POD Method

Abstract

To analyze the interrelations among impeller blade geometry, flow field fluctuation intensity and impeller-induced hydrodynamic noise of jet centrifugal pump (JCP), a Gappy proper orthogonal decomposition (POD) method combined with computational fluid dynamics/computational fluid acoustics (CFD/CFA) technique was proposed to reconstruct and predict the unsteady flow field fluctuation intensity and flow-induced noise in impeller region. The snapshot sets were composed of blade profile parameters, flow field fluctuation intensity data and the data of sound pressure level of hydrodynamic noise in the frequency domain. Similar mesh reconstruction and flow field interpolation were carried out to have the same number of flow field data. The snapshot sets were decomposed into a linear combination of orthogonal bases using the singular value decomposition (SVD) method. The orthogonal basis coefficients corresponding to the objective variables were fitted by the least square method. The results show that the proposed method has a good accuracy in predicting the flow field fluctuation intensity and flow-induced noise of the JCP impeller domain. The relative error of pressure fluctuation intensity field is less than 4.0%, relative velocity fluctuation intensity field is less than 3.0%, turbulent kinetic energy fluctuation intensity field is less than 4.5%, and impeller-induced hydrodynamic noise is less than 10%. Taking the method as a surrogate model to predict the flow field fluctuation intensity and the radiation level of hydrodynamic noise in the optimization process of centrifugal pump impeller, it could not only reduce the calculation amount and time significantly and improve optimization speed and efficiency greatly but could also provide a reference for vibration characteristics of the models.

A Review of the Flow-Induced Noise Study for Centrifugal Pumps

“…In the process of fluid motion, the physical quantities, such as pressure, velocity and vorticity, at a certain spatial point inside pumps fluctuate rapidly once as a blade passes. With blades continuously rotating, the physical quantities fluctuate periodically [26], that is, the rotor-stator interaction effect exists in whole pumps. As the main cause of flow-induced noise, the rotor-stator interaction could cause the frequency response characteristics of flow-induced noise at different monitoring points that are dominated by characteristic frequencies such as the blade-passing frequency (f b ) and its harmonic frequencies in a low frequency band.…”

Investigation on the Changing Characteristics of Flow-Induced Noise in a Centrifugal Pump

“…The rotor-stator interaction was the main cause of flow-induced noise. Generally, under the effect of rotorstator interaction, the physical quantities (pressure, velocity, etc) in pumps showed the periodic fluctuation characteristics [4], so the flow-induced noise reached to maximum at blade-passing frequency (f b ), and also decreased with the increase of frequency [5]. The cavitation, which could affect the hydraulic performance and pump structure, was another cause of flow-induced noise [6].…”

Analysis of Different POD Processing Methods for SPIV-Measurements in Compressor Cascade Tip Leakage Flow

“…The proper orthogonal decomposition (POD) method can decompose the examined flow field into orthogonal modes in space and identify the dominant mode based on energy rank [18,19]. It has been widely applied to both experimental and numerical data to identify some coherent structures, such as impeller flow [20], cylinder engine flow [21], wind turbine wake [22] and Jet and vortex actuator-induced flow [23]. Based on optimizing the mean square of the field variable, the POD method can extract flow structures of different scales.…”