Influence of Mechanical Draft Tube Fish Barrier on the Hydraulic Thrust of Small Francis Turbines

Faria, Marco Tulio C.; Paulino, Olair Gonçalves; Oliveira, Fernando Henrique de; Barbosa, Bruno Henrique Groenner; Martinez, Carlos Barreira

doi:10.1061/(asce)hy.1943-7900.0000256

Cited by 8 publications

(5 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In these two events, the death occurred afterward the barrier tests. (6) In some tests, in which there was not register of fish activity in the draft tube tailrace pipe, the pump speed was reduced to stimulate the fish entrance. However, in some tests at 20V, no individual entered the draft tube visualization region, even at zero speed.…”

Section: Test Results and Analysismentioning

confidence: 99%

“…Mechanical, electrical, optical, and acoustical principles have been employed to develop these mechanisms. Within all feasible repelling mechanisms, the mechanical fish barriers are the simplest and cheapest in terms of operation and maintenance costs, however they can cause considerable impact on the machine behavior [6]. The evaluation of new technologies for repelling mechanisms requires the development of experimental studies about their efficacy using prototypes or reduced models of hydrogenerators.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Model Development of a Fish Electromechanical Barrier for Hydraulic Turbines

Faria

Viana²,

Martinez³

2014

ije

View full text Add to dashboard Cite

The fish access into the draft tube of hydraulic turbines has caused numerous ecological accidents in several Brazilian hydropower plants. Many Brazilian fish species usually swim upstream for spawning and are attracted by the flow coming from the turbine tailrace pipe into the hydraulic machine. Some technical alternatives have been evaluated as feasible solutions to impede the fish entrance into hydraulic turbines. Electromechanical fish barriers appear to be a promising alternative to repel fishes from hydraulic turbine due to their small impact on the turbine flow and due to their capability of efficiently impeding the entrance of aquatic living beings into the turbine draft tube. This paper presents the development of a reduced model of an electromechanical barrier, designed to be installed on the draft tube stoplog guides, that is intended to impede the fish upstream movement through the turbine. A model of an axial-flow propeller turbine, at scale of 1:10.5, is specially designed for this work. The turbine test bench includes the turbine spiral case and draft tube, the turbine runner and the afterbay tank, which has been built to accommodate the fish individuals tested in this work. The efficacy tests of the electromechanical barrier model are performed at several operating conditions. The fish movement near the barrier is monitored by using small video cameras, which permit to record and to observe the fish reaction under the effect of electrical fields at the entrance of the turbine draft tube.

show abstract

Section: Test Results and Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Model Development of a Fish Electromechanical Barrier for Hydraulic Turbines

Faria

Viana²,

Martinez³

2014

ije

View full text Add to dashboard Cite

show abstract

“…Scholars reveal the dynamic excitation vibration mechanism inside the Francis turbine flow field by studying the pressure pulsation amplitude and frequency [8][9][10]. Numerous studies show that the noise and vibration of Francis turbines are related to pressure fluctuations [11]: mainly because the pressure changes the axial forces [12][13][14]. Some researchers have studied the instability and dangerous power swings at full load of a prototype Francis turbine from investigations on a reduced-scale model [15,16].…”

Section: Introductionmentioning

confidence: 99%

Flow Characteristics Analysis of a 1 GW Hydraulic Turbine at Rated Condition and Overload Operation Condition

Liu,

Wu,

Huang

et al. 2024

Processes

View full text Add to dashboard Cite

Flow stability is extremely important for hydraulic turbines, especially for 1 GW hydraulic turbines, and has a strong impact on mesh stability. However, turbines often operate under non-design conditions, and current research on this aspect is still lacking. So a model of the fluid domains of a high-quality installed 1 GW Francis turbine was established to investigate the flow characteristics of the turbine and fluid domains. CFD simulations of a 1 GW Francis turbine under rated load and overload operation conditions were performed. According to simulation results, when the turbine is under the overload operation condition, the internal flow stability of the 1 GW hydraulic turbine can be obviously different from that of the rated load. In the overload condition, the flow field is more turbulent and a large number of vortices are generated in the draft tube, resulting in significant changes in pressure, flow rate, and output. In order to improve calculation accuracy, a pure clearance model containing only clearances and pressure balance pipes was established. The results of the full flow channel and pure clearance were compared. It was found that under the rated operating condition and the overload condition, compared with the pure clearance model, the axial force of the runner calculated by the full flow channel model is approximately 2–7% biased, the radial force is biased by approximately 7–8%, and the leakage flow is smaller.

show abstract

“…To explore the influencing factors of the axial hydraulic force, many studies have focused on the runner clearance in the upper crown chamber and bottom ring chamber. It is been explored that the axial hydraulic force is caused by the pressure difference between the inner and outer surfaces of the runner's crown and the band and between the runner blade's suction and pressure sides [6,7]. The clearance flow can also cause [8,9].…”

Section: Introductionmentioning

confidence: 99%

Flow Characteristics Analysis of a High-Head Prototype Pump-Turbine During Turbine Start-Up: Effects of the Clearance

Zhang

Huang²,

Yin

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

View full text Add to dashboard Cite

The dramatic changes in the internal flow and the corresponding structural behavior during the turbine start-up transient process of pump-turbines are extremely complex. The clearances in the upper crown chamber and bottom ring chamber affect the results of the flow field and structural field of the pump-turbine runner. Most of the previous studies ignored the effects of the clearance flow field to simplify the numerical simulations. In this study, numerical calculations were performed on the entire flow passage of a high-head prototype pump-turbine during the start-up in turbine mode, and the model with and without the clearance are analysed respectively. The causes of the flow field characteristic difference and external characteristic difference caused by the existence of intermediate clearance in the model are studied in detail. The results show that the clearance flow field has a great influence on the axial forces on the runner, which is mainly due to the higher pressure of the clearance flow field compared with the flow field in the runner; At the same time, because the existence of clearance flow field only has a small effect on the distribution of internal flow field, the hydraulic torque of runner considering clearance effects is basically the same as the one without clearance.

show abstract

Influence of Mechanical Draft Tube Fish Barrier on the Hydraulic Thrust of Small Francis Turbines

Cited by 8 publications

References 3 publications

Model Development of a Fish Electromechanical Barrier for Hydraulic Turbines

Model Development of a Fish Electromechanical Barrier for Hydraulic Turbines

Flow Characteristics Analysis of a 1 GW Hydraulic Turbine at Rated Condition and Overload Operation Condition

Flow Characteristics Analysis of a High-Head Prototype Pump-Turbine During Turbine Start-Up: Effects of the Clearance

Contact Info

Product

Resources

About