Simulation and Experiments of Aerated Flow in Curve-Connective Tunnel with High Head and Large Discharge

2016 ◽  
Vol 14 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Shuai Li ◽  
Jian-min Zhang ◽  
Wei-lin Xu ◽  
Jian-gang Chen ◽  
Yong Peng ◽  
...  
Keyword(s):  
Aerated Flow ◽  
High Head ◽  
Large Discharge

Numerical Simulation of Ventilation Characteristics in a Hydropower Station Spillway Tunnel with High Head and Large Discharge

2014 ◽  
Vol 926-930 ◽  
pp. 3527-3530
Author(s):  
Hong Qing Zhang ◽  
Yi Long Lou ◽  
Wei Ping Xing ◽  
Jun Jun Tan
Keyword(s):  
Wind Speed ◽  
Hydropower Station ◽  
Aerated Flow ◽  
Speed Distribution ◽  
Vof Model ◽  
High Head ◽  
Spillway Tunnel ◽  
The Right ◽  
Ventilation Hole ◽  
Large Discharge

High wind speedandloudnoise usually occur in the hydropower station spillway tunnel, which will impact the producing environment of operators. In this paper, turbulent model and VOF modelwere combinedto simulate wind speed and the volume of ventilated airin ventilation holeandthreeaeratorsin the spillway tunnel on the right bank of a hydropower station in China. The results show thatVOF modelcan well simulate ventilated air induced by water drag, andthe volume of ventilated air in ventilation hole is the largest.Wind speed distribution on the longitudinal sectionof the inlet of ventilation hole is non-uniform,and loud noisewill occurthere. Wind speed on the left side of three aerators is higher than that on the right side. The results of the volume of ventilated airin threeaerators simulated by VOF modelare credible, but we should improve the VOF model to more accurately simulate aerated flow.

Analysis the Response of Aerated Flow Depth to the VOF Model

2014 ◽  
Vol 716-717 ◽  
pp. 767-770
Author(s):  
Hong Qing Zhang ◽  
Yi Long Lou ◽  
Qian Zhao ◽  
Wei Kai Tan
Keyword(s):  
Water Depth ◽  
Empirical Formula ◽  
Maximum Deviation ◽  
Flow Depth ◽  
Turbulent Model ◽  
Aerated Flow ◽  
Vof Model ◽  
High Head ◽  
Spillway Tunnel ◽  
Large Discharge

In order to analysis the response of aerated flow depth to the VOF model, in this paper, we used VOF combining turbulent model to simulate aerated flow depth in a hydropower station spillway tunnel with high head and large discharge in China. The results show that aerated flow depth is slightly larger than the experiment water depth, but the maximum deviation are not greater than 5% (except the pile number 0+605.236 m). So, using empirical formula to converse the calculate value of water depth into aerated flow depth can make up for the defects of the VOF model which cannot directly get aerated flow depth of the cross section inside the spillway tunnel. But the section water depth can’t be obtained by empirical formula calculation value conversion when cavity exists in the spillway tunnel.

Pressure Distribution of Pressure and Non-Pressure Sections of a Hydropower Station Spillway Tunnel

2014 ◽  
Vol 716-717 ◽  
pp. 244-247
Author(s):  
Hong Qing Zhang ◽  
Wei Kai Tan ◽  
Yi Long Lou ◽  
Qian Zhao
Keyword(s):  
Pressure Distribution ◽  
Model Experiment ◽  
Hydropower Station ◽  
Maximum Pressure ◽  
Turbulent Model ◽  
Sudden Drop ◽  
Sudden Enlargement ◽  
High Head ◽  
Spillway Tunnel ◽  
Large Discharge

In this paper, we used VOF combining turbulent model to simulate pressure distribution of pressure section and non-pressure section in a hydropower station spillway tunnel with high head and large discharge in China. The results show that in the pressure section of the spillway tunnel, the values of pressure of emergency gate slot, working gate and the pressing slope, getting from physical model experiment and numerical simulation, are all positive. While in the non-pressure section, the No.1、2、3 aerators of the sudden enlargement and sudden drop occur the maximum pressure. And at the back of the No.1、2、3 aerators, where the values of pressure are negative, forms cavity. The conclusions obtained can improve the design of spillway tunnel.

Elimination of upper bracket resonance in extremely high head Francis hydro-generators

2009 ◽  
Vol 16 (1) ◽  
pp. 119-127 ◽  
Author(s):  
Yongyao Luo ◽  
Zhengwei Wang ◽  
Guodong Chen ◽  
Zujian Lin
Keyword(s):  
High Head

Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits

2014 ◽  
Vol 70 (5) ◽  
pp. 871-877 ◽  
Author(s):  
Fahri Ozkan ◽  
M. Cihat Tuna ◽  
Ahmet Baylar ◽  
Mualla Ozturk
Keyword(s):  
Froude Number ◽  
High Speed ◽  
Water Mixture ◽  
High Speed Flow ◽  
Mixture Flow ◽  
Speed Flow ◽  
Aeration Efficiency ◽  
High Head ◽  
Closed Conduit ◽  
Air Vent

Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number.

scholarly journals On the Improvement in the Suction Performance of High-Head Axial-Flow Pumps

1968 ◽  
Vol 11 (48) ◽  
pp. 1056-1067
Author(s):  
Taijiro KASAI ◽  
Sigenori MATSUNAGA ◽  
Yukio KUNIKIYO ◽  
Haruo ISIBASI
Keyword(s):  
Axial Flow ◽  
High Head ◽  
Suction Performance
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