Suppression of Swirling Flow in a Conical Diffuser by use of J-groove.

博, 今村; 淳一, 黒川; 純, 松井; 修, 高村

doi:10.1299/kikaib.68.3325

Cited by 5 publications

(2 citation statements)

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“…Some passive flow control techniques are a) grooving of runner cone [28][29][30][31][32][33], b) exit stay apparatus (ESA) [34], c) fins in the draft tube [35], and d) baffles in the draft tube [36]. The grooving of the runner cone shows some improvements in the flow characteristics but cannot successfully mitigate the RVR.…”

Section: Introductionmentioning

confidence: 99%

A Novel Guide Vane System Design to Mitigate Rotating Vortex Rope in High Head Francis Model Turbine

Joy¹,

Raisee²,

Cervantes³

2022

IJFMS

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Guide vanes are a mechanical system used to direct flow in the desired direction. At lower operating conditions, implementing a guide vane system in the draft tube of a hydro-turbine can decrease the excess swirl in the flow and, thus, reduce pressure fluctuations. The present study discusses a numerical methodology to design an effective guide vane system in the draft tube of a high head Francis model turbine. The numerical method is computationally efficient and thus, saves excess computational time and data storage required for parametric analysis of the guide vane system. The aim is to mitigate the 'rotating' vortex rope with minimum additional losses in the turbine. The factors considered for the guide vane system design are a) number of guide vanes, b) chord length, c) span, d) inlet-outlet angles of the guide vanes, and e) their position in the draft tube. The parametric study comprises a) ideal guide vane design and b) realistic guide vane design study. The ideal guide vane design study was with the standalone draft tube domain. The realistic guide vane design study used the passage domains of the distributor, runner, and complete draft tube. From the ideal guide vane design study, a guide vane system with two or three guide vanes of chord 86% of runner radius and leading-edge span of 30% of runner radius effectively mitigates the rotating vortex rope. The system with three guide vanes is the most efficient when placed at some distance below the runner exit with mitigation above 95%

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Section: Introductionmentioning

confidence: 99%

A Novel Guide Vane System Design to Mitigate Rotating Vortex Rope in High Head Francis Model Turbine

Joy¹,

Raisee²,

Cervantes³

2022

IJFMS

View full text Add to dashboard Cite

show abstract

“…The grooving of the runner cone showed some improvements in the flow characteristics in the draft tube at PL [34][35][36][37][38][39]. This passive mitigation technique reduced the RVR amplitude but did not mitigate it entirely.…”

Section: Introductionmentioning

confidence: 99%