0
research-article

Analysis of the runner behavior during the start-up sequence in a bulb turbine model

[+] Author and Article Information
Maxime Coulaud

PhD Student, LAMH, Mechanical Engineering Dpt, Université Laval, Québec, Québec, G1V 0A6, Canada
maxime.coulaud.1@ulaval.ca

Jean Lemay

Professor, LAMH, Mechanical Engineering Dpt, Université Laval, Québec, Québec, G1V 0A6, Canada
jean.lemay@gmc.ulaval.ca

Claire Deschênes

Professor, LAboratoires de Machines Hydrauliques (LAMH), Mechanical Engineering Dpt, Université Laval, Québec, Québec, G1V 0A6, Canada
claire.deschenes@gmc.ulaval.ca

1Corresponding author.

ASME doi:10.1115/1.4041892 History: Received March 20, 2018; Revised October 23, 2018

Abstract

An experimental analysis of the start-up sequence of a bulb turbine was performed in a closed loop circuit, and analyses of global performances were conducted under three start-up conditions. In order to conduct a deeper analysis of the runner behavior, a runner blade was equipped with 26 sensors, which were used to evaluate the transient pressure field using an interpolation method. By checking the global performances of all the conditions, the flow rate evolution follows the GVO evolution only for the two slowest GVO test cases. Additionally, the use of defined dimensionless numbers allowed for some degree of universal evolution to be revealed, and for the peak of torque to be characterized. The pressure on the runner blades was also investigated. Although the runner operates like an impulse turbine at the beginning of the start-up sequence, its blades act like more airfoils when the torque reaches its peak. Moreover, the fluctuations at the end of the start-up sequence suggests that the stress on the blade could be more important than the stress observed on the driven shaft. Furthermore, local phenomena, such as suction on the pressure side of the runner blade near the shroud, were also observed on the pressure distribution, which is incongruent with the theoretical inlet velocity field estimated from global performances. These observations suggest the presence of a backflow and a cavitation pocket. Moreover, a flow instability probably occurs at low GVO speed and produces some torque fluctuations around the maximum torque value.

Copyright (c) 2018 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In