scholarly journals CFD analysis of flow pattern in S-Shape region for low specific speed Francis turbine

2021 ◽  
Vol 774 (1) ◽  
pp. 012098
Author(s):  
Katsutoshi Kobayashi ◽  
Yuta Tamura
Keyword(s):  
Flow Pattern ◽  
Francis Turbine ◽  
Cfd Analysis ◽  
Low Specific Speed ◽  
Specific Speed

Bowl-Type Diffusers for Low Specific-Speed Pumps: An Industrial Application

2006 ◽  
Author(s):  
Paolo Boncinelli ◽  
Roberto Biagi ◽  
Antonio Focacci ◽  
Umberto Corradini ◽  
Andrea Arnone ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Cfd Analysis ◽  
Aerodynamic Design ◽  
Three Dimensional Flow ◽  
Aerodynamic Efficiency ◽  
Recovery Capacity ◽  
Critical Problems ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Numerical Solver

In this paper, the aerodynamic design of a bowl–type diffuser for a low specific–speed pump is presented and described in detail. The main goal was to achieve an optimal configuration in terms of diffuser recovery capacity and stage aerodynamic efficiency, while satisfying severe constraints concerning stage size and multistage feasibility. Both geometrical parametrization tools and a fully–viscous three–dimensional numerical solver were exploited in the design process. The geometrical parameterization allowed one to control and modify the geometry of the component by changing a limited number of parameters. CFD analysis was exploited to assess the effectiveness of the geometrical modifications on the performance, and to identify critical problems. A number of aerodynamic ID coefficients with simple physical meanings were also introduced and used as a support to the design to synthesize the main feature of the strongly three–dimensional flow evolving in the component. As a result, a new stage configuration was developed according to the imposed constraints, whose performance is at the same level as standard pumps of the same class.

scholarly journals The Rotor-Stator Interaction Onboard A Low Specific Speed Francis Turbine

2020 ◽  
Vol 13 (2) ◽  
pp. 302-309
Author(s):  
Einar Agnalt ◽  
Bjørn Winther Solemslie ◽  
Pål-Tore Selbo Storli ◽  
Ole Gunnar Dahlhaug
Keyword(s):  
Francis Turbine ◽  
Rotor Stator Interaction ◽  
Low Specific Speed ◽  
Specific Speed

Simulation on Balde Duct Vortex in a Francis Turbine Runner Based on S-A Model

2013 ◽  
Vol 444-445 ◽  
pp. 476-478 ◽  
Author(s):  
Yong Zhong Zeng ◽  
Xiao Bing Liu
Keyword(s):  
Flow Field ◽  
Internal Flow ◽  
Optimal Operation ◽  
Francis Turbine ◽  
Operation Conditions ◽  
Low Load ◽  
Turbine Runner ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Load Conditions

If deviating from the optimal operation conditions, flow separation will occur on the blade of the runner in a low specific speed turbine. At this time, the turbulent flow of flow field in the blade duct will be in a strong non-equilibrium state, and thus the blade duct vortexes will be generated. To further study the mechanism of blade duct vortexes and to control the generation of these vortexes, Spalart-Allmaras (S-A) model was used to numerically simulate and calculate the internal flow in the low specific speed turbine runner under low load conditions. The blade duct vortexes in the turbine runner were accurately predicted. The effect of short blade in eliminating and reducing the vortexes in the low specific speed turbine runner was analyzed and compared.

Study on a Francis Turbine With Super-Low Specific Speed Applied in Cooling Towers

2010 ◽  
Author(s):  
Limin Zhang ◽  
Yuan Zheng ◽  
Daqing Zhou ◽  
Yuanting Mao
Keyword(s):  
High Efficiency ◽  
Cooling Tower ◽  
Research Work ◽  
Three Dimensional ◽  
Power Saving ◽  
Francis Turbine ◽  
Runner Blade ◽  
Water Head ◽  
Low Specific Speed ◽  
Specific Speed

The surplus water head of the industrial cooling tower is generally 4 to 15 meters. Using the surplus water head, a Francis turbine with super-low specific speed is designed to replace the fan motor in the cooling tower, which may achieve the purpose of power saving. This turbine is different from the conventional turbine used in hydropower station. To drive the fan to a rated speed, the turbine is required to have high efficiency and small size to meet the installation requirements under a certain flow or water head. Little research work on this type of turbine has been done home and abroad. In this paper, the runner blade airfoil was chiefly designed by three-dimensional numerical simulation through the whole flow passage of the turbine. According to the features of the turbine’s work environment, metal elliptical volute and single row ring guide vanes were applied in the structural design. By comparison and analysis an optimal model of which the efficiency can reach 86% was selected to make the physical model. The model test shows that the designed super-low specific speed Francis turbine can meet the dimension requirement and has high efficiency of 85.3% and stable performance that can be popularized and applied in the capable local places. The new type Francis turbine with super-low specific speed studied and developed in this paper can achieve the goal of reducing the energy consumption of the cooling tower. It can provide reference of using the surplus energy to the other industry.

Effect of the Exit System on the Performance of a Low Specific Speed Industrial Centrifugal Compressor Stage

2003 ◽  
Author(s):  
Jean-Luc Di Liberti
Keyword(s):  
Centrifugal Compressor ◽  
High Frequency ◽  
Rotating Stall ◽  
Cfd Analysis ◽  
Compressor Stage ◽  
Test Results ◽  
Centrifugal Compressor Stage ◽  
Surge Margin ◽  
Low Specific Speed ◽  
Specific Speed

A low specific speed stage was tested with two different size volutes and a return vane system. The stage was instrumented with pressure probes at various locations, including the inlet and discharge flanges, diffuser inlet, diffuser exit, and return vane inlet. Cobra probes were positioned at the diffuser inlet and the return vane inlet for the return vane configuration to measure the flow angles. High frequency transducers were installed in the diffuser. This paper presents the test results showing the effect of two different volute sizes and of the return vane system on surge margin, rotating stall onset, and overall rotor and stage performance. Rotating stall criteria are reviewed, since this stage was previously tested with a different diffuser pinch. The performance is compared with some CFD analysis.

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