The investigation of runner blade channel vortices in two different Francis turbine models

Cheng, Huan; Zhou, Lingjiu; Liang, Quanwei; Guan, Ziwu; Liu, Demin; Wang, Zhaoning; Kang, Wenzhe

doi:10.1016/j.renene.2020.04.015

Cited by 10 publications

(2 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are also some scholars who believe that the channel vortex inside the runner also affected the vibration of the turbine [9][10][11][12]. The flow characteristics within the draft tube and runner are intricate, and there is no consistent conclusion on the formation mechanism of the channel vortex and the vortex rope in the draft tube [13]. Liu et al [14] suggested that the larger incidence angle between the inflow angle and the blade angle on the leading edge of the runner was the formation factor of the channel vortex.…”

Section: Introductionmentioning

confidence: 99%

Study on Flow Characteristics of Francis Turbine Based on Large-Eddy Simulation

Xu,

Cheng,

Lin

et al. 2023

Water

View full text Add to dashboard Cite

The research object was a Francis turbine, and the working conditions at 100%, 75%, 50%, 25%, and 1% opening were determined by the opening size of the guide vane. Large-Eddy Simulation (LES) was adopted as a turbulence model method to conduct three-dimensional unsteady turbulent numerical simulation of the entire flow channel of a Francis turbine, and the flow situation of various parts of the turbine under different working conditions was obtained. The flow characteristics of each component under different working conditions were analyzed, and the hydraulic performance of each part was evaluated. The factors that affected the stability of hydraulic turbines were identified, and their formation mechanisms and evolution laws were explored. The results show that the guide vane placement angle was reasonable in the guide vane area, and the hydraulic performance was fine. The impact on the stability of the hydraulic turbine was small. Further research showed that the hydraulic performance was poor in the runner area, and there were flow separation and detachment phenomena in the flow field. This created a channel vortex in the runner blade channel. The channel vortex promoted the lateral flow of water and had a significant impact on the stability of the hydraulic turbine. The diffusion section of the draft tube can dissipate most of the kinetic energy of the water flow in the draft tube area, and it had a good energy dissipation effect. However, the was a large pressure difference between the upper and lower regions of the diffusion section, and it generated a backflow phenomenon. It created vortex structures in the draft tube, and the stability of the hydraulic turbine was greatly affected.

show abstract

Section: Introductionmentioning

confidence: 99%

Study on Flow Characteristics of Francis Turbine Based on Large-Eddy Simulation

Xu,

Cheng,

Lin

et al. 2023

Water

View full text Add to dashboard Cite

show abstract

“…Guo Pengcheng et al [17][18][19] carried out experiments with numerical models on Francis turbines to analyze the development mechanism of channel vortices and made a comparative analysis of the shapes of cavitation vortices inside the channel by using said models in experiments. Liu [20][21][22][23] et al used a high-speed camera to capture the channel vortex phenomenon during a test and found that the channel vortex occurs due to the influence of the attack angle at the blade inlet. Su Wentao et al [24] carried out numerical simulations and tests on a Francis turbine, which verified the feasibility and accuracy of the LES method based on a cavitation model in predicting the performance of Francis turbines under partial flow conditions, while Trivedi Chirag et al [25,26] used the LES method to simulate the load change of a Francis turbine and compared the results with experimental data.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Channel Vortex and Cavitation Performance of the Francis Turbine under Partial Flow Conditions

2021

View full text Add to dashboard Cite

To realize a multienergy complementary system involving hydropower and other energy sources, hydraulic turbines frequently run under partial flow conditions in which a unique flow phenomenon, the channel vortex, occurs in the runner, causing fatigue failure and even cavitation to the turbine blade. Cavitation severely shortens the service life of the unit and terribly limits the output of the turbine under partial flow conditions. In this paper, a numerical model of a Francis turbine was created with tetrahedral grids; the large eddy simulation (LES) method based on the WALE subgrid scale model and the Schnerr–Sauer cavitation model was adopted to carry out numerical simulation of the Francis turbine; and a vortex identification method based on the Q criterion was used to capture and analyze the channel vortex. The calculation results showed that a negative impact angle at the inlet of the runner occurred when the turbine ran under partial flow conditions, leading to three different types of channel vortexes in the blade channel. Also, different channel vortexes caused cavitation on different positions on the runner, and the volume change of cavitation showed periodic properties.

show abstract

Identification of the vortex in the main flow passage of a multiphase pump and the relationship with pressure fluctuation

Shi,

Tang,

et al. 2024

Energy Science & Engineering

View full text Add to dashboard Cite

This article investigates the evolution of vortex structures in the impeller channel of a multiphase pump. By capturing the vortices in the impeller channel using the vorticity and Q‐criterion, the generation location of the vortex structures is analyzed, and the pressure fluctuations induced by vortices in the main flow passage of the impeller are studied in terms of their time‐ and frequency‐domain characteristics. The relationship between the vorticity and the amplitude of pressure fluctuations at the main frequency of the impeller is further investigated. This study develops a method of identifying vortices in the impeller channel of the multiphase pump, and reveals the intrinsic connection between the vortices and pressure fluctuations in the main flow passage. These findings offer some suggestions for eliminating the influence of vortices and enhancing the pressurizing capabilities of multiphase pumps.

show abstract

The investigation of runner blade channel vortices in two different Francis turbine models

Cited by 10 publications

References 8 publications

Study on Flow Characteristics of Francis Turbine Based on Large-Eddy Simulation

Study on Flow Characteristics of Francis Turbine Based on Large-Eddy Simulation

Analysis of Channel Vortex and Cavitation Performance of the Francis Turbine under Partial Flow Conditions

Identification of the vortex in the main flow passage of a multiphase pump and the relationship with pressure fluctuation

Contact Info

Product

Resources

About