Unsteady Swirling Flows Arising in Straight Tubes

Tsurusaki, Hiromu

doi:10.5293/ijfms.2010.3.3.211

Cited by 2 publications

(4 citation statements)

References 4 publications

(5 reference statements)

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“…The dominant frequency depends on the shape of the turbine runner, the runner frequency, and the degree of guide vane opening [18,27,28].…”

Section: Pressure Oscillation In the Draft Tubementioning

confidence: 99%

“…The helical vortex rope is recognized as the main contributor of low frequency pressure oscillations in the draft tube. The dominant frequency depends on the shape of the turbine runner, the runner frequency, and the degree of guide vane opening [18,27,28]. In Tables 2 to 4, the dominant frequencies and the peak-to-peak amplitudes of the pressure oscillations at S11, S21, and S31 with four runner cone designs at ¼ 16 , 17 , 18 , 19 , and 20 are listed.…”

Section: Pressure Oscillation In the Draft Tubementioning

confidence: 99%

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The effect of runner cone design on pressure oscillation characteristics in a Francis hydraulic turbine

Zhou

Huai

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part A:

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Three-dimensional unsteady turbulent flow through the entire flow passage of a model Francis hydraulic turbine is simulated using the transition shear-stress transport turbulence model and verified with experimental data. Pressure oscillations with the original runner cone, an extended runner cone, an extended runner cone with grooves, and a round-top runner cone are analysed under five operating conditions. The computational results show that (1) runner cone design can change the distribution pattern of the vortex rope in the draft tube and narrow the zone of special pressure oscillation; (2) the dominant frequency of pressure oscillation in the draft tube at guide vane opening angle, ¼ 17 , is significantly decreased by runner cone design while the peak-to-peak amplitude increased; (3) varying guide vane opening alters the influence of runner cone design on pressure oscillation; (4) the modified runner cones are effective for low frequency pressure oscillations induced by the vortex rope in the draft tube but have little effect on blade frequency pressure oscillation induced by rotor-stator interaction; (5) the cavitation performance at ¼ 17 is decreased while that at ¼ 18 , 19 , and 20 is increased by runner cone design; and (6) the round-top runner cone is most effective in decreasing pressure oscillations and increasing turbine cavitation performance.

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“…The dominant frequency depends on the shape of the turbine runner, the runner frequency, and the degree of guide vane opening [18,27,28].…”

Section: Pressure Oscillation In the Draft Tubementioning

confidence: 99%

Section: Pressure Oscillation In the Draft Tubementioning

confidence: 99%

The effect of runner cone design on pressure oscillation characteristics in a Francis hydraulic turbine

Zhou

Huai

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part A:

View full text Add to dashboard Cite

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“…The dominant frequency is dependent on the shape of the runner and the runner frequency [18,19]. The distributions of pressure and velocity in section S1 without MGV and with different MGV openings are shown in Figs 8 and 9, respectively.…”

Section: Pressure Fluctuations In the Draft Tubementioning

confidence: 99%

“…The vortex rope is known as the major contributor of the low-frequency pressure fluctuations in the draft tube [17]. The dominant frequency is dependent on the shape of the runner and the runner frequency [18,19]. The distributions of pressure and velocity in section S1 without MGV and with different MGV openings are shown in Figs 8 and 9, respectively.…”

Section: Pressure Fluctuations In the Draft Tubementioning

confidence: 99%

Analysis of pressure oscillations in a Francis hydraulic turbine with misaligned guide vanes

Zheng

Huai

Lee

2009

Proceedings of the Institution of Mechanical Engineers, Part A:

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Three-dimensional unsteady turbulent flow in the entire flow passage of a model Francis turbine is simulated by adopting the realizable k−ε turbulence model. Using experimental data, the validity of the mathematical model is verified. Pressure oscillations are calculated for a model turbine attached with a misaligned guide vanes (MGV) device. Two MGV with five different MGV opening angles are selected for analysing the influence of MGV on pressure oscillations in the spiral case, guide vanes, runner, and draft tube. The computational results show that (a) the rotational frequency of the vortex rope remains unchanged despite different MGV openings, (b) the MGV device changes the peak-to-peak amplitude in a similar way as aligned guide vanes, (c) with increasing MGV opening, the amplitude of various frequency components in the draft tube vary in different ways, (d) a new frequency that is the product of the runner frequency and the number of MGV appears in the runner, and (e) with increasing difference between the MGV opening and the other guide vane openings, the amplitude of this new pressure oscillation increased.

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Unsteady Swirling Flows Arising in Straight Tubes

Cited by 2 publications

References 4 publications

The effect of runner cone design on pressure oscillation characteristics in a Francis hydraulic turbine

The effect of runner cone design on pressure oscillation characteristics in a Francis hydraulic turbine

Analysis of pressure oscillations in a Francis hydraulic turbine with misaligned guide vanes

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