Transient characteristics during the closure of guide vanes in a pump-turbine in pump mode

Transient characteristics during the closure of guide vanes in a pump-turbine in pump mode To achieve the flow mechanism during the closure of the guide vanes in a pump-turbine in pump mode, a three-dimensional (3-D) incompressible simulation using the shear stress transition (SST) k-ω turbulence model was performed. The dynamic mesh method was adopted to simulate the closing process of the guide vanes. Based on the validation of the steady experiments, the variation in performance characteristics (head, discharge, and torque), pressure, and velocity was presented, which shows dynamic instability at the end of the guide vanes closing process. Numerical results confirm that the dynamic instabilities at the end of the closing process originated from severe fluctuations that occurred in the guide and stay vanes. Detailed analyses of flow characteristics reveal that severe fluctuations occur due to vortices in the stay vanes, and a high-pressure circular ring in the vaneless space and a low-pressure circular ring between the guide vanes outlet and stay vanes inlet were identified. During the closing process of the guide vanes opening, the vortices appear in several passages initially, and then increasingly spread to all the passages. The position and rotating direction of the vortices vary with time. Using the Q-criterion method, the composition and evolution of vortex structures in stay vanes were identified. These structures comprise streamwise vortices, horseshoe-shaped vortices, and spanwise vortices, which lead to severe pressure fluctuations. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Renewable Energy Elsevier

Transient characteristics during the closure of guide vanes in a pump-turbine in pump mode

Loading next page...
 
/lp/elsevier/transient-characteristics-during-the-closure-of-guide-vanes-in-a-pump-5ASMFyruOd
Publisher
Elsevier
Copyright
Copyright © 2017 Elsevier Ltd
ISSN
0960-1481
eISSN
1879-0682
D.O.I.
10.1016/j.renene.2017.10.088
Publisher site
See Article on Publisher Site

Abstract

To achieve the flow mechanism during the closure of the guide vanes in a pump-turbine in pump mode, a three-dimensional (3-D) incompressible simulation using the shear stress transition (SST) k-ω turbulence model was performed. The dynamic mesh method was adopted to simulate the closing process of the guide vanes. Based on the validation of the steady experiments, the variation in performance characteristics (head, discharge, and torque), pressure, and velocity was presented, which shows dynamic instability at the end of the guide vanes closing process. Numerical results confirm that the dynamic instabilities at the end of the closing process originated from severe fluctuations that occurred in the guide and stay vanes. Detailed analyses of flow characteristics reveal that severe fluctuations occur due to vortices in the stay vanes, and a high-pressure circular ring in the vaneless space and a low-pressure circular ring between the guide vanes outlet and stay vanes inlet were identified. During the closing process of the guide vanes opening, the vortices appear in several passages initially, and then increasingly spread to all the passages. The position and rotating direction of the vortices vary with time. Using the Q-criterion method, the composition and evolution of vortex structures in stay vanes were identified. These structures comprise streamwise vortices, horseshoe-shaped vortices, and spanwise vortices, which lead to severe pressure fluctuations.

Journal

Renewable EnergyElsevier

Published: Apr 1, 2018

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off