Medial design of blades for hydroelectric turbines and ship propellers

Rossgatterer, M.; Jüttler, Bert; Kapl, Mario; Vecchia, Gabriele Della

doi:10.1016/j.cag.2012.03.022

Cited by 10 publications

(10 citation statements)

References 13 publications

(15 reference statements)

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“…In contrast to this, the resulting geometry must also be defined in a nonrestrictive fashion to ensure that an optimal design can be reached. Several studies suggest different approaches using parametric curves and surfaces, with degrees-offreedom corresponding to the specifications of the optimization tasks [29][30][31]. Following the classical definition, the threedimensional (3D) chamber surface of the runner blade can be described by combining one meridional projection of the runner with several conformal maps of the stream surfaces.…”

Section: Parametric Definition Of the Runnermentioning

confidence: 99%

Optimization of Francis Turbines for Variable Speed Operation Using Surrogate Modeling Approach

Iliev

Tengs²,

Trivedi³

et al. 2020

Journal of Fluids Engineering

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Previous studies suggested variable speed operation of Francis turbines as a measure to improve the efficiency at off-design operating conditions. This is, however, strongly dependent on the hydraulic design and, for an existing turbine, improvements can be expected only with a proper redesign of the hydraulic surfaces. Therefore, an optimization algorithm is proposed and applied to the runner of a low specific speed Francis turbine, with an optimization strategy specifically constructed to improve the variable speed performance. In the constrained design space of the reference turbine, the geometry of the replacement runner is parametrically defined using 15 parameters. Box-Behnken method was used to populate the design space with 421 unique samples, needed to train fully quadratic response surface models of three characteristic efficiencies defined by the proposed objective function. Computational fluid dynamics was used to calculate the responses for each sample. The parametric study showed that the anticipated variation of the shape of the hill-chart, needed to improve the variable speed performance of the turbine, is limited within a narrow range. The presented method is general and can be applied to any specific speed in the Francis turbine range, for both synchronous speed and variable speed optimization tasks.

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Section: Parametric Definition Of the Runnermentioning

confidence: 99%

Optimization of Francis Turbines for Variable Speed Operation Using Surrogate Modeling Approach

Iliev

Tengs²,

Trivedi³

et al. 2020

Journal of Fluids Engineering

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“…In this way the shape of the whole blade can be obtained as a smooth surface without discontinuities and abrupt changes in shape. The mean surface of the blade is obtained by imposing the previously defined blade angle distribution on the construction curves that were defined through equation (1), according to equation (4).…”

Section: Runner Parametrizationmentioning

confidence: 99%

“…Hence, of outmost importance is the integration of a flexible design tool to the optimization procedure capable to modify automatically the blade shape in successive iterations. Such tools typically rely on polynomial or spline curves for the definition of a blade angle distribution across a streamline and lofting and surface interpolation techniques to construct the final blade [3,4]. In this paper a Francis turbine design method is proposed using a geometric design tool based on the combination of traditional methods [5] and a modified parametric description of the blade.…”

Section: Introductionmentioning

confidence: 99%

Development of a hydraulic turbine design method

Anagnostopoulos¹,

Papantonis²

2013

AIP Conference Proceedings

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In this paper a hydraulic turbine parametric design method is presented which is based on the combination of traditional methods and parametric surface modeling techniques. The blade of the turbine runner is described using Bezier surfaces for the definition of the meridional plane as well as the blade angle distribution, and a thickness distribution applied normal to the mean blade surface. In this way, it is possible to define parametrically the whole runner using a relatively small number of design parameters, compared to conventional methods. The above definition is then combined with a commercial CFD software and a stochastic optimization algorithm towards the development of an automated design optimization procedure. The process is demonstrated with the design of a Francis turbine runner.

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“…The turbomachinery industry often relies on specialized tools for the digital representation of blade row geometries. 13,14 These are mostly based on a bottom-up approach, according to which blade sections are generated and, then, skinned (via NURBS or some other kind of spline interpolation) to yield 3D blade shapes. In References 13,14, the blade sections shape is controlled mostly by means of metal angles and thickness distributions.…”

Section: Introductionmentioning

confidence: 99%

Continuous adjoint‐based shape optimization of a turbomachinery stage using a 3D volumetric parameterization

Trompoukis

Τσιάκας

Asouti

et al. 2023

Numerical Methods in Fluids

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This work presents a novel volumetric parameterization technique along with the continuous adjoint method to support gradient‐based CFD shape optimization of turbomachinery stages. The proposed parameterization retains axisymmetry and periodicity by acting on a transformed coordinate system. The same volumetric model controls the shape and the computational volume mesh in a seamless manner, avoiding the additional use of a mesh deformation tool. Moreover, it is differentiated to compute mesh sensitivities (i.e., derivatives of nodal coordinates with respect to the design variables) and is combined with the flow and continuous adjoint, multi‐row solvers of the in‐house PUMA software. Flow field solutions in successive rows communicate based on the mixing plane approach; the development of continuous adjoint to the latter is also presented in this article. The adjoint to the turbulence model and distance‐from‐the‐wall (Hamilton–Jacobi) equations are solved, increasing the accuracy of the computed sensitivity derivatives. All these tools run on modern GPUs, accelerating both flow/adjoint solutions and shape/mesh manipulations. The capabilities of these tools are demonstrated in the shape optimization of the rotor blades of the MT1 high‐pressure, transonic, turbine stage, aiming at maximum stage isentropic efficiency with constraints on stage reaction and inlet capacity.

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Medial design of blades for hydroelectric turbines and ship propellers

Cited by 10 publications

References 13 publications

Optimization of Francis Turbines for Variable Speed Operation Using Surrogate Modeling Approach

Optimization of Francis Turbines for Variable Speed Operation Using Surrogate Modeling Approach

Development of a hydraulic turbine design method

Continuous adjoint‐based shape optimization of a turbomachinery stage using a 3D volumetric parameterization

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