Based on CFX Numerical Simulation of Francis Turbine Runner

2013 ◽  
Vol 456 ◽  
pp. 207-210
Author(s):  
Fang He
Keyword(s):  
Numerical Simulation ◽  
Guide Vane ◽  
Prediction Method ◽  
Internal Flow ◽  
Francis Turbine ◽  
Flow State ◽  
Hydro Turbine ◽  
Runner Blade ◽  
Vibration Prediction ◽  
Turbine Runner

This paper presents a vibration prediction method for Francis turbine: Provided with advanced CFX software, Numerical simulation of movable guide vane and Turbine runner’s internal flow state. From the source of hydraulic vibration, Focus on numerical analysis, numerical simulation for the cutting thickness of the runner blade. After analysis of the influence of the blade of hydraulic vibration. To explore new ways for the hydro turbine control hydraulic vibration.

Hydraulic Characteristics of the New Type Bulb Turbine With Micro-Head

2013 ◽  
Author(s):  
Lingyu Li ◽  
Yuan Zheng ◽  
Daqing Zhou ◽  
Zihao Mi
Keyword(s):  
Numerical Simulation ◽  
Cfd Simulation ◽  
Guide Vane ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Three Dimensions ◽  
Guide Vanes ◽  
Runner Blade ◽  
Cfd Method ◽  
Bulb Turbine

The head of low-head hydropower stations is generally higher than 2.5m in the world, while micro-head hydropower resources which head is less than 2.5m are also very rich. In the paper, three-dimensional CFD method has been used to simulate flow passage of the micro-head bulb turbine. The design head and unit flow of the turbine was 1m and 3m3/s respectively. With the numerical simulation, the bulb turbine is researched by analyzing external characteristics of the bulb turbine, flow distribution before the runner, pressure distribution of the runner blade surface, and flow distribution of the outlet conduit under three different schemes. The turbine in second scheme was test by manufactured into a physical model. According to the results of numerical simulation and model test, bulb turbine with no guide vane in second scheme has simpler structure, lower cost, and better flow capacity than first scheme, which has traditional multi-guide vanes. Meanwhile, efficiency of second scheme has just little decrease. The results of three dimensions CFD simulation and test results agree well in second scheme, and higher efficiency is up to 77% which has a wider area with the head of 1m. The curved supports in third scheme are combined guide vanes to the fixed supports based on 2nd scheme. By the water circulations flowing along the curved supports which improve energy transformation ability of the runner, the efficiency of the turbine in third scheme is up to 82.6%. Third scheme, which has simpler structure and best performance, is appropriate for the development and utilization of micro-head hydropower resources in plains and oceans.

scholarly journals Influence of guide vane clearance on internal flow of medium-specific speed Francis turbine

2019 ◽  
Vol 240 ◽  
pp. 022056
Author(s):  
Gnanasekaran Kishor Kumar ◽  
Tadachika Tanaka ◽  
Naoki Yamaguchi ◽  
Toui Taniwaki ◽  
Kazuyoshi Miyagawa ◽  
...  
Keyword(s):  
Guide Vane ◽  
Internal Flow ◽  
Francis Turbine ◽  
Specific Speed

Inter-Blade Vortex Characteristics With the Blockage Effects of Runner Blade in a Francis Hydro Turbine Model

2019 ◽  
Author(s):  
Seung-Jun Kim ◽  
Jin-Hyuk Kim ◽  
Young-Seok Choi ◽  
Yong Cho ◽  
Jong-Woong Choi
Keyword(s):  
Flow Rate ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Operating Conditions ◽  
Low Flow ◽  
Hydro Turbine ◽  
Runner Blade ◽  
Performance Reduction ◽  
Turbine Model ◽  
Low Flow Rate

Abstract This study presents the numerical analysis on the inter-blade vortex characteristics along with the blockage effects of runner blade in a Francis hydro turbine model with various flow rate conditions. The turbine model showed different flow characteristics in the runner blade passages according to operating conditions, and inter-blade vortex was observed at lower flow rate conditions. This inter-blade vortex can lead to performance reduction, vibration, and instability for smooth operation of turbine systems. The previous study on blockage effects on various runner blade thickness, showed its influence on hydraulic performance and internal flow characteristics at low flow rate conditions. Therefore, the inter-blade vortex characteristics can be altered with the blockage effects at low flow rate conditions in a Francis hydro-turbine. For investigating the internal flow and unsteady pressure characteristics, three-dimensional steady and unsteady Reynolds-averaged Navier-Stokes calculations are performed. These inter-blade vortices were captured at the leading and trailing edges close to the runner hub. These vortex regions showed flow separation and stagnation flow while blockage effects contributed for decreasing the inter-blade vortex at low flow rate conditions.

Numerical simulation of fluid added mass effect on a francis turbine runner

2007 ◽  
Vol 36 (6) ◽  
pp. 1106-1118 ◽  
Author(s):  
Q.W. Liang ◽  
C.G. Rodríguez ◽  
E. Egusquiza ◽  
X. Escaler ◽  
M. Farhat ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mass Effect ◽  
Added Mass ◽  
Francis Turbine ◽  
Turbine Runner ◽  
Fluid Added Mass

Effect of Runner Blade Thickness on Flow Characteristics of a Francis Turbine Model at Low Flowrates

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Seung-Jun Kim ◽  
Young-Seok Choi ◽  
Yong Cho ◽  
Jong-Woong Choi ◽  
Jin-Hyuk Kim
Keyword(s):  
Stokes Equations ◽  
Guide Vane ◽  
Vortex Formation ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Francis Turbine ◽  
Hydroelectric Power ◽  
Runner Blade ◽  
Blade Thickness ◽  
Interblade Vortices

Abstract Francis turbines are often used for generating hydroelectric power, but their performance characteristics significantly depend on the operating conditions. In particular, interblade vortices in the passages between runner blades can occur at low flowrates, which can degrade performance, and increase vibrations and instability during operation. In a previous study, we showed that the hydraulic performance and flow characteristics depend on the flow passage area of runner blades under low-flowrate conditions. Under such operating conditions, the runner blade thickness can affect the interblade vortex characteristics, and in turn, affect the performance of the turbine. In this study, we investigated the effect of runner blade thicknesses in the presence of interblade vortices under low flowrates; steady- and unsteady-state Reynolds-averaged Navier–Stokes equations were solved using a shear stress transport as a turbulence model. The interblade vortices were described well at the near leading and trailing edges near the hub. These vortex regions showed flow separation and stagnation flow, and the interblade vortex characteristics were dependent on the high-magnitude unsteady pressures at the low-frequency region. For the same guide vane opening, at lower flowrates, higher blockage ratios reduced interblade vortex formation and unsteady pressure.

Numerical Investigations of Model Propeller Turbine Performance Under Different Guide Vane Opening

2008 ◽  
Author(s):  
Zhou Daqing ◽  
Bo Qu ◽  
Zheng Yuan
Keyword(s):  
Guide Vane ◽  
Three Dimensional ◽  
Small Opening ◽  
Hydro Turbine ◽  
Runner Blade ◽  
Turbine Performance ◽  
Water Head ◽  
Large Opening ◽  
Turbulent Models ◽  
Cfd Method

In the paper, CFD method is applied to investigate model propeller turbine performance under different guide vane opening. First, the whole passage geometric models of model propeller turbine have been built with 0° runner blade under five kinds of guide vane opening, and subdivided with about 1.78 million cells of unstructured mesh. Then, three dimensional turbulent flow computations are made at the water head of H = 1m and the runner speed of n = 217.4 r/min, with the two turbulent models, RNG k-ε and Spalart-Allmadas. Furthermore, the curves of moment value and axial hydraulic thrust value are plotted and compared with experimental curves, which shows that numerical results agree well with experimental data, and Spalart-Allmadas model has better precision than RNG k-ε model. Finally, the flow fields of different parts in the turbine passage are displayed and analyzed respectively under the large, normal and small guide vane opening, which shows the fact that the rotating direction of vortex in the axial diffuse of draft tube is opposite by comparing the large opening with the small opening, and the flow field is in disorder and unsteady especially under the small opening. On the whole, CFD method has many unique advantages and has played more and more important roles on the investigations of hydro turbine performance.

scholarly journals Numerical Investigation of Flow Field and Energy Loss in a Centrifugal Pump as Turbine

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jingze Li ◽  
Dongrong Meng ◽  
Xun Qiao
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Energy Loss ◽  
Entropy Generation ◽  
Flow Separation ◽  
Guide Vane ◽  
Great Influence ◽  
Internal Flow ◽  
Asymmetric Structure ◽  
Centrifugal Pumps

Centrifugal pumps as turbine (PAT) are widely used in petrochemical and water conservancy industries. The research on the internal flow field and energy loss of PAT is of great significance to improve the performance and efficiency of PAT. In this paper, experimental and numerical simulation methods are used to study the energy loss and flow field. The results show that the numerical simulation method can accurately simulate the internal flow field of PAT. And the entropy generation theory is applied to visualize the internal energy loss of PAT through the comparison of total pressure loss and entropy generation. The highest energy loss among PAT components is the guide vane. The loss in the guide vane is mainly caused by the flow separation caused by the wake of the guide vane and the asymmetric structure of the volute. The losses in the impeller are mainly due to flow separation and wake. Besides, the unsteady simulation results show that rotor-stator interaction has a great influence on the gap between the impeller and the guide vane. The research results provide a reference for the design of the PAT. This study is beneficial to studying the dynamic and static interference and PAT vibration to improve the stability of the PAT.

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.

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