Simulations and Experimental Investigations on the Acoustic Characterization of Centrifugal Pumps of Different Specific Speed

• Published in: International journal of turbomachinery, propulsion and power Vol. 4; no. 3; p. 16
• Main Authors: Lehr, Christian, Linkamp, Andreas, Aurich, Daniel, Brümmer, Andreas
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 02.07.2019
• Subjects: Acoustic excitation; Acoustic propagation; acoustic transmission; Acoustics; Cavitation; centrifugal pump; Centrifugal pumps; Dipoles; Discharge pipes; Dynamic pressure; Evaluation; Numerical models; one-dimensional model; Parameters; Plane waves; pressure pulsation; Pressure sensors; scattering parameters; Simulation; Sound transmission; Suction; Valves; Velocity; Volutes; Wave propagation
• ISSN: 2504-186X; 2504-186X
• DOI: 10.3390/ijtpp4030016

Subject of discussion are simulations and experimental investigations on the acoustic characterization of three single stage centrifugal pumps of different specific speed. In operation, these pump-types generate pressure pulsation at blade passing frequency, primarily due to rotor-volute-interaction. In order to determine the acoustic excitation it is necessary to know about the pumps’ acoustic transmission parameters. In this paper, a one-dimensional numerical model for transient time-domain simulation is presented, which takes into account the pump geometry as well as the volutes’ structural behaviour by means of the local effective speed of sound. Numerical results for the transmission characteristics of the three different pumps are shown in terms of scattering matrices and evaluated against parameters calculated from measurement results. The experimental analyses are carried out using dynamic pressure sensors in both the suction and the discharge pipe. Assuming solely plane wave propagation, the complex acoustic field on each side is evaluated independently. The so called “two source” method is then used to determine the transmission parameters of the pumps in standstill for a range of frequencies experimentally. Subsequently, the acoustic excitation at varying rotational speed is evaluated by means of measurements at the pumps in operation and presented as monopole and dipole source types for cavitation-free conditions.