Numerical simulation of flow through orifice energy-dissipators in Xiaolangdi flood-discharge tunnel

Cavitation of orifices is one of the main problems of the Xiaolangdi flood discharge tunnels. Along with the decompression experiment, the flow field was calculated by using an axis-symmetrical Kappa - epsilon turbulence model. The calculated pressure distribution was compared with the measured data and in agreement with each other. The calculated results show that few of the cavitation bubbles generating at the orifice edge can reach the wall under the calculation condition, the force applied on the orifice surface and the flow pattern before the orifice may be improved obviously by adding the vortex elimination ring at the upper side of the orifice.