Regions of positive slope in the pressure-discharge characteristics can result in a reduction or even lack of damping of system instabilities. They are therefore one of the major concerns in design and operation of centrifugal pumps as they are limiting the admissible operating range. The considered preliminary hydraulic design of an industrial double suction pump of medium specific speed ν = 0.410 (0.205 per impeller side) shows a marked saddle in the energy-discharge characteristic associated to a sudden drop of efficiency versus discharge at part load. Unsteady RANS type flow simulations are performed using hexahedral meshes with 2.5 million nodes to model the inlet casing, the shrouded double sided impeller with 2 × 7 blades, the diffuser with 12 blades and the volute. In unsteady solution monitoring, low frequency (below blade passing frequencies) phenomena are noticed. Therefore, simulation times of up to 10 impeller revolutions at each flow rate are requested to achieve statistically steady behavior of the flow judged on global performance numbers and circumferential flow rate distribution. The numerical simulations emphasize a drop in the characteristic, though at a lower flow rate than found on the test rig. It is shown to be associated to a one-sided separation in the diffuser, further leading to an unbalanced flow rate distribution of about 10% of flow rate between both sides of the impeller. There is a region of hysteresis, where both configurations with balanced and unbalanced flow rate distributions can be obtained for the same global flow rate. The asymmetric flow distribution leads to asymmetric velocity profiles at the impeller-diffuser interface which results in a strongly vortical flow in the diffuser channels, where an important amount of energy is dissipated in regions of increased viscous and turbulent shear.
Skip Nav Destination
Close
Sign In or Register for Account
ASME/JSME 2007 5th Joint Fluids Engineering Conference
July 30–August 2, 2007
San Diego, California, USA
Conference Sponsors:
- Fluids Engineering Division
ISBN:
0-7918-4289-4
PROCEEDINGS PAPER
Unsteady Numerical Simulations of the Flow Related to the Unstable Energy-Discharge Characteristic of a Medium Specific Speed Double Suction Pump
Francois Avellan,
Francois Avellan
EPFL, Lausanne, Switzerland
Search for other works by this author on:
Philippe Dupont
Philippe Dupont
Sulzer Pumps Ltd., Winterthur, Switzerland
Search for other works by this author on:
Olivier Braun
EPFL, Lausanne, Switzerland
Francois Avellan
EPFL, Lausanne, Switzerland
Philippe Dupont
Sulzer Pumps Ltd., Winterthur, Switzerland
Paper No:
FEDSM2007-37550, pp. 971-977; 7 pages
Published Online:
March 30, 2009
Citation
Braun, O, Avellan, F, & Dupont, P. "Unsteady Numerical Simulations of the Flow Related to the Unstable Energy-Discharge Characteristic of a Medium Specific Speed Double Suction Pump." Proceedings of the ASME/JSME 2007 5th Joint Fluids Engineering Conference. Volume 2: Fora, Parts A and B. San Diego, California, USA. July 30–August 2, 2007. pp. 971-977. ASME. https://doi.org/10.1115/FEDSM2007-37550
Download citation file:
- Ris (Zotero)
- Reference Manager
- EasyBib
- Bookends
- Mendeley
- Papers
- EndNote
- RefWorks
- BibTex
- ProCite
- Medlars
Close
Sign In
5
Views
0
Citations
Related Proceedings Papers
Related Articles
An Investigation of Nonlinear Flow Oscillations in a High-Pressure Centrifugal Pump
J. Turbomach (November,2015)
A Deterministic Stress Model for Rotor-Stator Interactions in Simulations of Average-Passage Flow
J. Fluids Eng (June,2002)
Flow in a Centrifugal Pump Impeller at Design and Off-Design Conditions—Part II: Large Eddy Simulations
J. Fluids Eng (January,2003)
Related Chapters
Dynamic Behavior of Pumping Systems
Pipeline Pumping and Compression Systems: A Practical Approach
Introduction
Design of Mechanical Bearings in Cardiac Assist Devices
Turbocompressors
Pumps and Compressors