Specifications

Corresponding author: Zhao, Y.P. ([e-mail])
Source title: IOP Conference Series: Earth and Environmental Science
Abbreviated source title: IOP Conf. Ser. Earth Environ. Sci.
Volume: 15
Issue: PART 6
Monograph title: 26th IAHR Symposium on Hydraulic Machinery and Systems - Session 4:
Advances in Computational and Experimental Techniques
Issue date: 2012
Publication year: 2012
Article number: 062049
Language: English
ISSN: 17551307
E-ISSN: 17551315
Document type: Conference article (CA)
Conference name: 26th IAHR Symposium on Hydraulic Machinery and Systems
Conference date: August 19, 2012 - August 23, 2012
Conference location: Beijing, China
Conference code: 95632
Publisher: Institute of Physics Publishing, Temple Circus, Temple Way, Bristol, BS1 6BE, United
Kingdom
Abstract: For a bulb turbine, it has a low head and a big runner diameter, and the free surface
influences the flow at the inlet and outlet of the turbine, which bring many problems such as
vibration, cracks and cavitation to the turbine. Therefore, it is difficult to get the precise internal
flow characteristics through a numerical simulation with conventional ideal flow conditions. In
this paper, both numerical and experimental methods are adopted to investigate the flow
characteristics at the inlet and outlet of the bulb turbine with considering free surface. Firstly,
experimental and numerical studies in a low head pressure pipeline are conducted, and the
corresponding boundary condition according with reality is obtained through the comparison
between the model test result and the CFD simulation result. Then, through an analysis of the
velocity and pressure fields at the inlet of the bulb turbine at different heads, the flow
characteristics and rules at the entrance of the bulb turbine have been revealed with considering
free surface; Finally, the performance predictions for a bulb turbine have been conducted by
using the obtained flow rules at the inlet as the boundary condition of a turbine, and the causes
that lead to non-uniform forces on blades, cavitation and vibration have been illustrated in this
paper, which also provide a theory basis for an accurate numerical simulation and optimization
design of a bulb turbine. © Published under licence by IOP Publishing Ltd.
Number of references: 5
Main heading: Inlet flow
Controlled terms: Boundary conditions - Bulb turbines - Cavitation - Computational
fluid dynamics - Computer simulation - Hydraulic machinery - Numerical methods -
Surfaces - Turbomachine blades
Uncontrolled terms: CFD simulations - Experimental and numerical studies - Flow
charac-teristics - Flow rules - Free surfaces - Ideal flow - Internal flow
characteristics - Low head - Model tests - Non-uniform - Numerical and