|
|
|
| Experimental study on influence of stepped overflow dam slope on aeratied characteristics and negative pressure of step surface |
| QIU Yi,YANG Jurui*,CHEN Weixing,REN Zhongcheng |
| Modern Agricultural Engineering College, Kunming University of Science and Technology, Kunming, Yunnan 650500, China |
|
|
|
|
Abstract In order to explore the influence of the slope of the stepped dam face under high water head and large single wide flow rate on the aerated characteristics of the stepped face and negative pressure of the integrated joint energy dissipation method of the wide tail pier + stepped overflow dam + energy dissipation tank, taking Ahai Hydropower Station as a prototype, the transport equations were established using the speed scale and the length scale respectively, the VOF and three-dimensional RNG-turbulence models of water-gas two-phase flow were introduced, and the geometric reconstruction format was used to iteratively generate free water surfaces. Three slopes of 51.34°, 53.13° and 56.98° were studied by numerical simulation. The results show that when the slope increases, the length of the aerated cavity on the step surface increases first and then decreases. When the slope is 53.13°, the length of the aerated cavity on the step surface is the longest, which is 7.5 m. The change of the aeratied concentration of the step surface is consistent with the change of the length of the aeratied cavity, the slope increases, the aeration concentration of the step surface increases first and then decreases, and the aeration concentration after the cavity section of each scheme is less than 3% of the minimum protective aeration concentration of the step surface. At this aeration concentration, cavitation damage will occur on the step surface. The negative pressure of the step surface is bimodal, and the maximum negative pressure peak appears at the second peak. The double peak of negative pressure increases with the slope. When the slope is 56.98°, the negative pressure is the largest, and the value is -42.34 kPa.
|
|
Received: 08 August 2019
|
|
|
|
|
|
|
