Model Study On Hydraulics Of Air-Entraimented Flow On Stepped Spillways

Based on model experiment, hydraulics of air- entrainmented flow on stepped spillways are studied.They mainly include flow form of air-entrainmented water, computational methods of surface line on stepped spillways, rules of intensity of pressure distribution,and also include mechanisms of air entrainment, consistency distribution of air entrainment and energy dissipations on stepped spillways after the aerator was set on the beginning of the step on the stepped spillways.Compared with smooth surface spillway, in virtue of its especial structure, flow form and configurations of stepped spillways are more complex. Especially, the engineers pay close attention to issues of Hydrodynamic cavitation and erosion. This paper studys the questions of air- entrainmented flow on stepped spillways. The researches show that after the aerator was set on the beginning of the step on the stepped spillways flow form are improved and aerator is the same with air- entrainmented demand under different flux and stepped spillways can fully aerate. Hydrodynamic cavitation and erosion on stepped spillways are derated and stream harasses are minished and at the same time stepped spillways exert functions of energy dissipations.This paper deeply reseaches hydraulics characteristics of air- entrainmented flow, computational methods of surface line, rules of intensity of pressure distribution,the length of cavity, convergent point of air- entrainmented flow, rules of consistency distribution of air entrainment and energy dissipations and gains the formula of surface line, the length of cavity, convergent point of air- entrainmented water, aerate amount of blowhole and expounds the intensity of pressure distribution on horizontal, vertical side and along the way and works over concentrations of air- entrainmented water on different height aerator face and along the way and provide the warrants for the designs of stepped spillways.