Pressure recovery of axial flow turbine draft tube with inlet swirl

This study presents the numerical and experimental investigations of flow behavior in an axial flow turbine draft tube model with cross-section changing from annular to rectangular. Forced vortex type of tangential velocity was introduced upstream of diffuser inlet with Reynolds number of 40,000 and...

Full description

Saved in:
Bibliographic Details
Main Authors: Augusto, Gerardo L., Culaba, Alvin B., Gan Lim, Laurence A., Maglaya, Archie B., Piseth, Sok
Format: text
Published: Animo Repository 2015
Subjects:
Online Access:https://animorepository.dlsu.edu.ph/faculty_research/12014
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: De La Salle University
Description
Summary:This study presents the numerical and experimental investigations of flow behavior in an axial flow turbine draft tube model with cross-section changing from annular to rectangular. Forced vortex type of tangential velocity was introduced upstream of diffuser inlet with Reynolds number of 40,000 and different rotational rates of 0.0, 0.168, 0.336 and 0.504. In this study, air was used as a working substance instead of water. I-type hot-wire probe and pressure transducers were used to determine the velocity components and mean wall pressure coefficients in each test cross-section, respectively. To further verify the experimental results, ANSYS Fluent software was also used to obtain the velocity profiles in each test cross-section of turbine draft tube. Numerical results were compared with experimental data and have found some degree of similarities with dimensionless velocity profiles at diffuser inlet and momentum flux ratio. Improvement of diffuser performance at a moderate inlet swirl was achieved as compared with that obtained from non-swirling inlet flow. Further increase of inlet swirl was found to deteriorate the pressure recovery due to the onset of vortex breakdown.