Study on Unstable Characteristics of Centrifugal Pump under Different Cavitation Stages

• Published in: Journal of thermal science Vol. 28; no. 4; pp. 608 - 620
• Main Authors: Dong, Liang, Shang, Huanhuan, Zhao, Yuqi, Liu, Houlin, Dai, Cui, Wang, Ying
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.08.2019; Springer Nature B.V
• Subjects: Bubbles; Cavitation; Centrifugal force; Centrifugal pumps; Classical and Continuum Physics; Computational fluid dynamics; Elastic waves; Engineering Fluid Dynamics; Engineering Thermodynamics; Fluid flow; Heat and Mass Transfer; High speed photography; Impellers; Internal flow; K-epsilon turbulence model; Physics; Physics and Astronomy; Product design; Pulsation; Stress concentration; Turbulence models; Unsteady flow; Visual signals; Vorticity; cavitation development stage; centrifugal pump; pressure pulsation; cavitation bubble distribution; radial force
• ISSN: 1003-2169; 1993-033X
• DOI: 10.1007/s11630-019-1136-2

In order to reveal the regularity of unsteady flow of centrifugal pump under different cavitation stages, a visual closed test-bed is built to collect signals such as the distribution of cavitation bubbles at the impeller inlet and external characteristics, etc. in the process of cavitation of centrifugal pumps. Combined with the shape and distribution of bubbles captured by high-speed photography, the cavitation stage of the centrifugal pump is divided. In addition, the variation of vorticity distribution, pressure pulsation and radial force of centrifugal pump under different cavitation stages are studied using the standard k - ε turbulence model and the Kunz cavitation model. Main contributions are as follows: The cavitation bubbles can absorb the energy of vortex core to a certain extent and increase the volume of vortex core. Cavitation bubbles can also block the flow-path and induce the distortion of the internal flow field, resulting in unstable pressure waves that cause a significant increase in pressure pulsation rate. Besides, with the development of cavitation, the radial force on the impeller tends to remain invariable first and then decrease, and trajectory of the radial force changes from closed to open.