Author(s): Xiaoqun Wang; Jijian Lian; Dongming Liu
Linked Author(s): Jijian Lian
Keywords: Ir demand; Air–water stratified flow; Design optimization; Interfacial shear stress; Negative pressure; Spillway tunnel
Abstract: Accurate calculation of air demand is fundamental in the design of air ducts in a spillway tunnel. However, it was often underestimated by empirical formulas in previous studies. In this paper, an air–water stratified flow model, in which the air and water are coupled by a new interfacial shear stress formulation, is proposed. The model is verified by using prototype data and numerical CFD results and proved to give better prediction of air demand for the spillway tunnel of the Jinping-I hydraulic project in China. In order to reduce the unfavourable high velocity of air in the air ducts, the model is also applied to optimize the design of air ducts of the Jinping-I project. We conclude that the model proposed in this paper can give more accurate results than the previous empirical formulas for air demand and is more convenient than 3D numerical models for engineering designers.