Teixeira, Joao AmaralSmith, Carly Jane2018-03-162018-03-162017-05http://dspace.lib.cranfield.ac.uk/handle/1826/13098The quest for greater pump efficiency and improved reliability has focused research topics in the understanding of pump hydraulic and dynamic behaviours. On-Design pump performance has been optimised utilising modern design strategies incorporating Computational Fluid Dynamics technology to predict and simulate the fluid flow in a pump. The fluid conditions within the arrangement of an impeller and collector present a complex unsteady flow phenomenon, which give rise to fluid structure interaction. Periodic hydraulic excitation forces are generated as a consequence. The interaction forces increase as the flow recirculation grows; the flow becomes less uniform at the impeller periphery. Thus, the highest magnitude of forces is observed at low flow and high flow operating conditions. They are impacted onto the rotor and transmitted to the bearing housing, although the forces are not quantitatively known. Lateral analysis of a pump rotor can demonstrate the rotor will not traverse or operate within a region of a critical speed, however, bearing housing vibration can be excessive and outside acceptable limits when operating at part load. The rationale of the project was therefore to employ a numerical modelling technique to capture hydraulically induced vibration caused by the interaction of the rotor and stator. A series of transient numerical analyses were carried out to investigate the unsteady fluctuating pressure field within a single stage pump for five operating conditions. The hydraulic excitation forces were captured and incorporated into a rotordynamic model where the corresponding displacement vibration were evaluated. It was shown that the highest estimated displacement vibration was at the low flow operating condition and at the cutwater region. An experimental campaign of the single stage pump validated the unsteady pressure fluctuations within an acceptable margin of two percent for nominal flow and five percent for low flow operating point. Greater variations were found when comparing the numerical and experimental approximations to the displacement vibration.en© Cranfield University, 2015. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.CC0 1.0 UniversalVibrationComputational fluid dynamicsRotor-stator interactionRotordynamicsThesis