Author(s): Shuai Li; Yang Jing; Jianminzhang; Jing Nie
Linked Author(s): Shuai Li
Keywords: Tunnel; Aeration and cavitation; Hydraulic characteristics; Numerical simulation; Experimental investigation
Abstract: One of the major problems caused by high-speed flow in tunnel of the High Dam project is flow cavitation which can cause wall surface cavitation erosion. Cavitation damage occurs frequently at some certain range of downstream of the anti-arc segmental in a tunnel with large discharge and high velocity flow. Feedback analysis shows that the main reason is due to the complexity of the flow pattern at the anti-arc segmental, strong turbulent flow, high-speed flow under the influence of centrifugal force leads to high gradient of pressure, air entrainment effect is not ideal and lack of aeration protection. Aeration is an effective measure to release cavitation erosionproblem of high-speed flow tunnel. Hydraulic characteristics of flow such as water surface profile, velocity distribution, pressure distribution, flow cavitation number, and cavity morphology were investigated by the conduction of large scale experiments, as well as the method of VOF and k-εturbulent model was used to simulate the tunnel of a hydropower station. The calculated results are in good agreement with the experimental data, showed that by combining thek-εdouble equations turbulence model with VOF method can well simulate the flow in complicated tunnel. The results show that each of the aerator decorated reasonable and hasstable aerated cavity, the type of aeratoris basically reasonable, the pressure distribution of anti-arc segmental of tunnel is uniform, the cavitation number distribution tends to be stable, which promotes thecavitation erosion characteristic of the tunnel flow.
Year: 2013