School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China E-mail:
Water Sci Technol. 2021 May;83(9):2259-2270. doi: 10.2166/wst.2021.137.
The baffle drop shaft is widely used in deep tunnel drainage systems due to its fine applicability and high energy dissipation. To fully study the turbulence characteristics and energy dissipation mechanism of baffle drop shafts, a 1:25 scale physical model test and a numerical simulation based on the Realizable k-ε model and Volume of Fluid (VOF) method were performed. The results showed that a baffle spacing that is too dense or too sparse is not conducive to energy dissipation and discharge. The minimum baffle spacing is the optimal structural design at the design flow rate when the flow regime is free-drop flow. The energy dissipation calculation model established in this paper has high accuracy for calculating the energy dissipation rate on the baffles in free-drop flow. The energy dissipation modes of the shaft can be divided into inlet energy dissipation, baffle energy dissipation, and shaft-bottom energy dissipation. Baffles play a major role in the energy dissipation at low flow rates, and the proportions of inlet and shaft-bottom energy dissipation increase with the increase in flow rate.
挡板跌水井由于适用性好、消能效果高而在深隧排水系统中得到广泛应用。为了充分研究挡板跌水井的紊流特性和消能机理，采用 1:25 比尺的物理模型试验和基于 Realizable k-ε 模型和 VOF 方法的数值模拟进行研究。结果表明，挡板间距过密或过疏都不利于消能和泄流。当水流流态为自由跌落流时，在设计流量下，最小挡板间距是最佳的结构设计。本文建立的能量耗散计算模型对自由跌落流中挡板上的能量耗散率具有较高的计算精度。竖井的能量耗散模式可分为进口能量耗散、挡板能量耗散和竖井底部能量耗散。挡板在低流量下对能量耗散起主要作用，随着流量的增加，进口和竖井底部能量耗散的比例增加。
