A numerical and experimental study on cavitation in positive displacement pumps and its application in valve design optimization

  • Aldo Iannetti

Student thesis: Doctoral Thesis

Abstract

A comprehensive and transient Computational Fluid Dynamic model of a Positive Displacement reciprocating pump in cavitating condition was developed in order to study the main features and the causes of cavitation in this kind of device. Several sensitivity analyses were also carried out in order to identify the most influential parameters on cavitation; the design of the inlet valve as well as the operating conditions were found to be the main parameters playing an important role in cavitation. To complete the numerical study, a sensitivity analysis on the air content in the water was carried out.;This highlighted the importance of the physical properties of the working liquid in influencing the vapour generation during cavitation. The second part of the project was dedicated to the experimental analysis; a test rig replicating the numerical model was designed and built. The experimental tests were carried out and the results were compared to the numerical data obtained in the previous part. The comparison revealed a reasonable accuracy as well as good consistency although numerical problems were found in the way the cavitation model accounted for the influence of the air dissolved in the water which was overestimated. The validated numerical model was utilised to modify the design of the inlet valve.;A new model of the valve was presented and described, it was demonstrated capable of minimising the vapour generation under the same operating condition with respect to the initial valve design. The modification proposed was implemented in the design of new valves which are already being manufactured and tested in the field, they will be introduced into the market afterwards. The project is the demonstration that numerical tools based on CFD are nowadays ready to effectively support designers and industries in bringing down the cost of the engineering process of new and more efficient products.
Date of Award24 Sep 2015
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsWeir Group plc (The)
SupervisorMatthew Stickland (Supervisor) & William Dempster (Supervisor)

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