Suppression of Performance Curve Instability of a Mixed Flow Pump by Use of J-groove

Saha, Sankar L.; Kurokawa, Junichi; Matsui, Jun; Imamura, Hiroshi

doi:10.1115/1.1287855

Cited by 53 publications

(10 citation statements)

References 15 publications

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“…Roussopoulos and Monkewitz 23 used an anti-cavitation lip on a model Kaplan turbine blade, and found it could reduce the circulation of vortex and presumably the danger of cavitation. Kurokawa and co-workers 24–27 first put forward the J-groove flow control technology and found that the J-groove could weaken the swirl flow and cavitating flow in the draft tube and mixed-flow pump. Zhang 28 researched the effect on the unstable characteristics of the axial-flow pump, and proposed a new method to mitigate the tip vortex cavitation by the flow control technology.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of the groove effect on the tip leakage vortex cavitating flow

Fei

Zhang

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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In this paper, the groove effect on the tip leakage vortex cavitating flow characteristics of a simplified NACA0009 hydrofoil with tip gap is studied. Considering local rotation characteristics and curvature effects of the tip leakage vortex flow, the rotation-curvature corrected shear-stress-transport turbulence model is applied to simulate the time-averaged turbulent flow. The Zwart–Gerber–Belamri cavitation model is used to simulate the cavitating flow. The results show that the groove could affect the tip leakage vortex cavitating flow. The groove enhances the interaction between the tip leakage flow and main flow, and then it affects the cavitation of the tip leakage vortex. Compared with the non-groove case, for groove cases of αgre ≤75°, the tip leakage vortex cavitating flow is suppressed, the flow pattern in the gap is improved, and the mean leakage velocity Vlk < 0.8. The region of high leakage velocity is eliminated and the distribution of the pressure is more uniform. The tip leakage vortex cavitation area is reduced, and the maximum decrease is 72.90%. While for groove cases of αgre≥90°, neither the tip leakage vortex cavitating flow nor flow pattern in the tip gap is ameliorated, the mean leakage velocity Vlk lies the range from 0.90 to 0.96. The region of high leakage velocity still exists and even the tip leakage vortex cavitation area is increased. Based on three-dimensional streamlines and vorticity transport equation, the interaction between the tip leakage flow and main flow leads to the variation of the tip leakage vortex cavitating flow. This paper aims for a useful reference to mitigate the tip leakage vortex cavitation and control the influence of the tip leakage vortex cavitating flow for the hydraulic machinery.

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Section: Introductionmentioning

confidence: 99%

Numerical analysis of the groove effect on the tip leakage vortex cavitating flow

Fei

Zhang

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…The J-Groove controls the angular momentum effectively in the main flow effectively for a wide range of turbo-machinery. 15,16 Kurokawa et al. 17 applied the J-Groove on a conical diffuser wall instead of a Francis turbine draft tube to mitigate swirl flow.…”

Section: Introductionmentioning

confidence: 99%

Suppression of cavitation in the draft tube of Francis turbine model by J-Groove

Chen

Choi

2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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Cavitation is recognized as a phenomenon that can cause serious damage to a hydro turbine and can reduce its performance when operating at off-design point. This is an undesired phenomenon, which needs to be improved. In order to suppress the cavitation in the Francis turbine draft tube, a technology with grooved draft tube named J-Groove is introduced in the Francis turbine. The Francis turbine performance and the internal flow characteristic are investigated both with and without J-Groove installation by the experimental method and numerical simulation. Visualization was used to capture the cavitation rope in the Francis turbine draft tube to compare with the computational fluid dynamics analysis result. The results show that the turbine performance both with and without J-Groove installation is quite similar. Regardless of impact on performance of Francis turbine by J-Groove, it suppresses the cavitation vortex rope and pressure fluctuation in the Francis turbine draft tube efficiently.

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“…When installed near the entrance of an impeller, J-groove has succeeded in suppressing the whirl of inlet flow, which made the performance-curve instability characterized by a rising head-capacity curve very stable. Thus J-groove can suppress surge without dropping the maximum efficiency in mixed flow and axial flow pumps [3] [4]. When installed at the entrance of diffuser of a centrifugal flow type, rotating stall in a vaned and a vaneless diffusers has been perfectly suppressed in the entire flow range and the pressure fluctuation has disappeared [5] [6].…”

Section: Introductionmentioning

confidence: 99%

J-Groove Technique for Suppressing Various Anomalous Flow Phenomena in Turbomachines

Kurokawa¹

2011

International Journal of Fluid Machinery and Systems

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In operating a turbomachine at off-design conditions various instabilities caused by anomalous flow phenomena occur and sometimes lead to the damage of a turbomachine. In order to avoid these phenomena various devices characteristic to each phenomenon have been developed, however they make turbomachines large-sized and cause efficiency drop. The present author has developed a very simple and innovative device, termed "J-groove," of suppressing various anomalous flow phenomena commonly by controlling the angular momentum of the main flow. It has been revealed that J-groove makes an operation of a turbomachine stable in all flow range, causes little efficiency drop, and can be easily applied to an existing machine. Here is reviewed totally the results of suppressing various anomalous flow phenomena in turbomachines.

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Suppression of Performance Curve Instability of a Mixed Flow Pump by Use of J-groove

Cited by 53 publications

References 15 publications

Numerical analysis of the groove effect on the tip leakage vortex cavitating flow

Numerical analysis of the groove effect on the tip leakage vortex cavitating flow

Suppression of cavitation in the draft tube of Francis turbine model by J-Groove

J-Groove Technique for Suppressing Various Anomalous Flow Phenomena in Turbomachines

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