Analysis of the Swirling Flow Downstream a Francis Turbine Runner

Susan-Resiga, Romeo; Ciocan, Gabriel Dan; Anton, I.; Avellan, François

doi:10.1115/1.2137341

Cited by 157 publications

(72 citation statements)

References 20 publications

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“…This study revealed that ζ is highly sensitive to the changes of each inlet velocity profile parameters of each equation given by [13].…”

Section: Objective Functionmentioning

confidence: 99%

“…The vortex equations proposed by [13] were established to represent a swirling flow produced by a constant pitch Francis runner, eq. (1-2).…”

Section: Inlet Velocity Profilementioning

confidence: 99%

“…Axial and tangential velocity profiles downstream a runner have been matched with analytic profiles given by the same set of equations. More specifically [13] proposed an outlet runner swirl criteria to avoid an unexpected sudden efficiency drop at certain discharge. This study included the axial and circumferential velocity components at the runner outlet for 17 operating points.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, inspired by [10] and [13], it was assumed that through an automatic optimization process, an inlet velocity parameterization managed by a Genetic Algorithm could build the best velocity flow field for a particular draft tube. This will give us the opportunity to study different draft-tube flow structures provoked by different inlet velocity profiles achieving a better understanding of the flow losses.…”

Section: Introductionmentioning

confidence: 99%

“…[13] can be applied to an axial turbine to investigate and improve draft tube performance. [14] and [15], matched the experimental axial and tangential velocity profiles downstream of a Kaplan runner with the analytical profiles.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Quantitative and qualitative analysis of the flow field development through T99 draft tube caused by optimized inlet velocity profiles

Galván

Reggio

Guibault

et al. 2015

International Journal of Fluid Machinery and Systems

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The effect of the inlet swirling flow in a hydraulic turbine draft tube is a very complex phenomenon, which has been extensively investigated both theoretically and experimentally. In fact, the finding of the optimal flow distribution at the draft tube inlet in order to get the best performance has remained a challenge. Thus, attempting to answer this question, it was assumed that through an automatic optimization process a Genetic Algorithm would be able to manage a parameterized inlet velocity profile in order to achieve the best flow field for a particular draft tube. As a result of the optimization process, it was possible to obtain different draft-tube flow structures generated by the automatic manipulation of parameterized inlet velocity profiles. Thus, this work develops a qualitative and quantitative analysis of these new draft tube flow field structures provoked by the redesigned inlet velocity profiles. The comparisons among the different flow fields obtained clearly illustrate the importance of the flow uniformity at the end of the conduit. Another important aspect has been the elimination of the re-circulating flow area which used to promote an adverse pressure gradient in the cone, deteriorating the pressure recovery effect. Thanks to the evolutionary optimization strategy, it has been possible to demonstrate that the optimized inlet velocity profile can suppress or mitigate, at least numerically, the undesirable draft tube flow characteristics. Finally, since there is only a single swirl number for which the objective function has been minimized, the energy loss factor might be slightly affected by the flow rate if the same relation of the axial-tangential velocity components is maintained, which makes it possible to scale the inlet velocity field to different operating points.

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“…This study revealed that ζ is highly sensitive to the changes of each inlet velocity profile parameters of each equation given by [13].…”

Section: Objective Functionmentioning

confidence: 99%

“…The vortex equations proposed by [13] were established to represent a swirling flow produced by a constant pitch Francis runner, eq. (1-2).…”

Section: Inlet Velocity Profilementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning