Suppression of Cavitation in a Francis Turbine Runner by Application of 3D Inverse Design Method

Okamoto, Hidenobu; Gotō, Akira

doi:10.1115/fedsm2002-31192

Cited by 4 publications

(11 citation statements)

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“…This blade calculation approach based on inviscid flow-tangency condition is widely used in the inviscid IDM and it can also be applied to viscous flow case by using the transpiration technique [41,42], in which the blade geometry is updated based on the calculated normal and tangential velocity according to mass conversion. Equations (8), (14), and (16) constitute the closed equations of the three-dimensional IDM, and the blade geometry is calculated in an iterate way.…”

Section: Blade Geometry Calculation Based On Flow Tangential Conditionmentioning

confidence: 99%

“…Normally, the low-pressure region happens at the position where the pressure load is large, and it can be suppressed by shifting the blade loading maximum to a different streamwise location. By doing this, the low-pressure region on blade surfaces can be controlled directly and effectively, and therefore the cavitation can be suppressed effectively [13,14,22] and the suction performance can be improved [48,49]. As mentioned above, the blade stacking condition (blade lean) can also have an influence on the static pressure distribution at specific positions of the impeller, and it can also be used to suppress cavitation [13,14,48].…”

Section: Suppression Of Cavitationmentioning

confidence: 99%

“…The blade shape is calculated based on the flow-tangency condition at the blade surfaces. The method is efficient and robust and is widely used in different turbomachinery such as pumps [9][10][11][12], turbines [13,14], compressors [15][16][17], diffusers [18][19][20], inducers [21,22], and so on. The flow calculation approach in this three-dimensional IDM is based on potential flow theory without viscosity.…”

Section: Introductionmentioning

confidence: 99%

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Three-Dimensional Inverse Design Method for Hydraulic Machinery

2019

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Hydraulic machinery with high performance is of great significance for energy saving. Its design is a very challenging job for designers, and the inverse design method is a competitive way to do the job. The three-dimensional inverse design method and its applications to hydraulic machinery are herein reviewed. The flow is calculated based on potential flow theory, and the blade shape is calculated based on flow-tangency condition according to the calculated flow velocity. We also explain flow control theory by suppression of secondary flow and cavitation based on careful tailoring of the blade loading distribution and stacking condition in the inverse design of hydraulic machinery. Suggestions about the main challenge and future prospective of the inverse design method are given.

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Section: Blade Geometry Calculation Based On Flow Tangential Conditionmentioning

confidence: 99%

Section: Suppression Of Cavitationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Three-Dimensional Inverse Design Method for Hydraulic Machinery

2019

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“…The three-dimensional inverse design method has been applied successfully to pump [12], compressor [13], and conventional hydraulic turbine [14][15][16] so far. In the inverse design of a Francis turbine, the loading distribution and the blade stacking condition (blade lean angle) are analyzed and it is found that different blade lean angles can change the pressure distribution on the blade surface, and influence the runner performances [15].…”

Section: Introductionmentioning

confidence: 99%

“…In the inverse design of a Francis turbine, the loading distribution and the blade stacking condition (blade lean angle) are analyzed and it is found that different blade lean angles can change the pressure distribution on the blade surface, and influence the runner performances [15]. In order to reduce the probability of cavitation, the blade loading at both the band and crown should be fore loaded [14]. Since the flow calculation in the three-dimensional inverse design method is based on potential flow theory with no consideration of the fluid viscosity, simulation with high fidelity [17] is necessary for the design verification.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Inverse Design of Low Specific Speed Turbine for Energy Recovery in Cooling Tower System

2018

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A three-dimensional inverse design of a low specific speed turbine is studied, and a set of design criteria for low specific speed turbine runner is proposed, including blade loading distributions and blade lean angles. The characteristics of the loading parameters for low specific speed turbine runner are summarized by analyzing the suction performance of different loading positions, loading slopes and blade lean angles based on the orthogonal experiment design and range analysis. It is found that the blade loading distribution at the band plays a more important role than it does at the crown and it should be fore loaded for both band and crown. The blade lean angle at the blade leading edge should be negative. Then, the blade is optimized through the inverse method by fixing blade lean angle, based on the response surface method. After seeking the optimal value of the response surface function, the optimal result of the design parameters is obtained, which is in conformity with the design criteria and verifies the rationality of the established design criteria for low specific speed turbine.

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Bulletin of the Polish Academy of Sciences: Technical Sciences

Krzemianowski

2019

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The paper concerns the engineering design of guide vane and runner blades of hydraulic turbines using the inverse problem on the basis of the definition of a velocity hodograph, which is based on Wu's theory [1,2]. The design concerns the low-head double-regulated axial Kaplan turbine model characterized by a very high specific speed. The three-dimensional surfaces of turbine blades are based on meridional geometry that is determined in advance and, additionally, the distribution of streamlines must also be defined. The principles of the method applied for the hydraulic turbine and related to its conservation equations are also presented. The conservation equations are written in a curvilinear coordinate system, which adjusts to streamlines by means of the Christoffel symbols. This leads to significant simplification of the computations and generates fast results of three-dimensional blade surfaces. Then, the solution can be found using the method of characteristics. To assess usefulness of the design and robustness of the method, numerical and experimental investigations in a wide range of operations were carried out. Afterwards, the so-called shell characteristics were determined by means of experiments, which allowed to evaluate the method for application to the low-head (1.5 m) Kaplan hydraulic turbine model with the kinematic specific speed (»260). The numerical and experimental results show the successful usage of the method and it can be concluded that it will be useful in designing other types of Kaplan and Francis turbine blades with different specific speeds.

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Suppression of Cavitation in a Francis Turbine Runner by Application of 3D Inverse Design Method

Cited by 4 publications

References 0 publications

Three-Dimensional Inverse Design Method for Hydraulic Machinery

Three-Dimensional Inverse Design Method for Hydraulic Machinery

Three-Dimensional Inverse Design of Low Specific Speed Turbine for Energy Recovery in Cooling Tower System

Bulletin of the Polish Academy of Sciences: Technical Sciences

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