Numerical and Experimental Study on a Model Draft Tube with Vortex Generators

Tian, Xiaoyong; Zheng, Yuan; Pan, Huachen; Sun, Bin

doi:10.1155/2013/509314

Cited by 6 publications

(4 citation statements)

References 17 publications

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“…The sizes of these fins were 70 mm 3 30 mm (small size), 145 mm 3 55 mm (middle size), and According to the model draft tube simulation and experiment, 11 the VGs should be installed at the vortex development section. In this hydraulic turbine, the section is located at 100-120 mm away from the inlet section of this draft tube.…”

Section: Geometric Model and Structured Gridsmentioning

confidence: 99%

“…10 Although the draft tube with VG has been studied, there was no detailed analysis for a real hydroturbine. 11 In this study, to explore when, where and how to use VG in a draft tube, a real hydraulic turbine was studied by the method of computational fluid dynamics (CFD). [12][13][14] Full-ported structured grids of every part of turbine passage were built up.…”

Section: Introductionmentioning

confidence: 99%

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Improvement of hydro-turbine draft tube efficiency using vortex generator

Tian

Pan

Hong

et al. 2015

Advances in Mechanical Engineering

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Computational fluid dynamics simulation was employed in a hydraulic turbine (from inlet tube to draft tube). The calculated turbine efficiencies were compared with measured results, and the relative error is 1.12%. In order to improve the efficiency of the hydraulic turbine, 15 kinds of vortex generators were installed at the vortex development section of the draft tube, and all of them were simulated using the same method. Based on the turbine efficiencies, distribution of streamlines, velocities, and pressures in the draft tube, an optimal draft tube was found, which can increase the efficiency of this hydraulic turbine more than 1.5%. The efficiency of turbine with the optimal draft tube, draft tube with four pairs of middle-sized vortex generator, and draft tube without vortex generator under different heads of turbine (5-14 m) was calculated, and it was verified that these two kinds of draft tubes can increase the efficiency of this turbine in every situation.

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Section: Geometric Model and Structured Gridsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improvement of hydro-turbine draft tube efficiency using vortex generator

Tian

Pan

Hong

et al. 2015

Advances in Mechanical Engineering

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“…Some scholars also apply this technology in the research of hydraulic turbines. Tian et al [15,16] studied the application of VGs by numerical simulations and experiments based on a model draft tube. Their results show that by choosing the optimal VG parameters, such as the installation type, installation position, blade-to-blade distance, and blade inclination angle, the draft tube-equipped VGs can effectively raise the static pressure recovery coefficients and working stability.…”

Section: Introductionmentioning

confidence: 99%

Effects of an Inlet Vortex on the Performance of an Axial-Flow Pump

et al. 2020

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The formation of an inlet vortex seriously restricts axial-flow pump device performance and poses a great threat to the safe and stable operation of the entire system. In this study, the change trends of an inlet vortex and its influence on an axial-flow pump are investigated numerically and experimentally in a vertical axial-flow pump device. Four groups of fixed vortex generators (VGs) are installed in front of the impeller to create stable vortices at the impeller inlet. The vortex influence on the performance of pump device is qualitatively and quantitatively analyzed. The vortex patterns at different positions and moments in the pump device are explored to reveal the vortex shape change trend in the impeller and the pressure fluctuation induced by the vortex. The reliability and accuracy of steady and unsteady numerical results are verified by external characteristics and pressure fluctuation experimental results. Results show that it is feasible to install VGs before the impeller inlet to generate stable vortices. The vortex disturbs the inlet flow fields of the impeller, resulting in significant reductions of the axial velocity weighted average angle and the axial velocity uniformity. The vortex increases the inlet passage hydraulic loss and reduces the impeller efficiency, while it only slightly affects the guide vane and outlet passage performance. The vortex causes a low-frequency pressure pulsation and interacts with the impeller. The closer the vortex is to the impeller inlet, the more significant the impeller influence on the vortex. The blade cuts off the vortex in the impeller; afterwards, the vortex follows the blade rotation, and its strength weakens.

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“…Force motor is the key component of hydraulic servo valve. Moving coil liner force motor is widely used in hydraulic servo valve [1][2][3]. However, there are some problems in current moving coil linear force motor.…”

Section: Introductionmentioning

confidence: 99%

Study of a New High Frequency Moving Coil Linear Force Motor for Electro Hydraulic Servo Valve

Chen

Yang

2012

AMR

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There are some problems in moving coil linear motor for Electro-hydraulic servo valve, such as big weight, small electromagnetic force, long response time and small bandwidth. After simulation analysis on permanent magnet placement and permanent magnet magnetization direction, it is found that distribution of magnetic field lines is uneven, magnetic flux density is low, and magnetic field lines are not vertical with the coil current direction. To solve these problems, a new type of linear force motor with 5 rings stack Halbach permanent magnet array structure is put forward. Through using the new structure, the weight and volume of motor can be reduced, and the electromagnetic force can be increased. Simulation results show that for the new structure, under the coil displacement change, the output electromagnetic force changes little and can maintain good linearity. Using permanent magnet with same volume, the electromagnetic force produced by new force motor is 2.5 times as it is produced by current motor. If the electromagnetic forces produced by two structures are same, the step response time of new type can be decreased of 14.3%, and the bandwidth can be improved to 2 times.

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Numerical and Experimental Study on a Model Draft Tube with Vortex Generators

Cited by 6 publications

References 17 publications

Improvement of hydro-turbine draft tube efficiency using vortex generator

Improvement of hydro-turbine draft tube efficiency using vortex generator

Effects of an Inlet Vortex on the Performance of an Axial-Flow Pump

Study of a New High Frequency Moving Coil Linear Force Motor for Electro Hydraulic Servo Valve

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