A CFD study on the mechanisms which cause cavitation in positive displacement reciprocating pumps

Iannetti, Aldo and Stickland, Matthew and Dempster, William (2015) A CFD study on the mechanisms which cause cavitation in positive displacement reciprocating pumps. Journal of Hydraulic Engineering, 1 (1). pp. 47-59. ISSN 2332-8215 (https://doi.org/10.17265/2332-8215/2015.01.005)

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Abstract

A transient multiphase CFD model was set up to investigate the main causes which lead to cavitation in positive displacement (PD) reciprocating pumps. Many authors such as Karsten Opitz [1] agree on distinguishing two different types of cavitation affecting PD pumps: flow induced cavitation and cavitation due to expansion. The flow induced cavitation affects the zones of high fluid velocity and consequent low static pressure e.g. the valve-seat volume gap while the cavitation due to expansion can be detected in zones where the decompression effects are important e.g. in the vicinity of the plunger. This second factor is a distinctive feature of PD pumps since other devices such as centrifugal pumps are only affected by the flow induced type. Unlike what has been published in the technical literature to date, where analysis of positive displacement pumps are based exclusively on experimental or analytic methods, the work presented in this paper is based entirely on a CFD approach, it discusses the appearance and the dynamics of these two phenomena throughout an entire pumping cycle pointing out the potential of CFD techniques in studying the causes of cavitation and assessing the consequent loss of performance in positive displacement pumps.