Sudden Or + Sudden Expansion Aerator Hydraulic Characteristics Of

With the rapid development of the construction of water conservancy and hydropower projects, high speed flow problems which are caused by the high head and large unit Flow of the high dam discharge buildings have become increasingly prominent. Aeration and cavitation have been the focus of high-speed flow study all the time. Setting Aeration facilities to make high-speed flow aeration in the spillway construction is an effective measure to reduce and avoid cavitation damage. Therefore, the study of the aerator's hydraulic characteristics is of great practical significance, especially on the security and stability issues of the discharge buildings because of the characteristics of the aerated spillway flow.At present, the numerical simulation technology is applied increasingly in the study of Shape Optimization of hydraulic structures since it is simple and easy to change the parameters with low cost. However, the two-phase flow simulation of water vapor, especially in the aerated flow mathematical model and theory, is still not mature enough, more efforts needed to be done in the simulation.Based on trical simulation, to conduct the comparative analysis of the hydraulic characteristics of the size and the sudden drop or sudden sudden expansion and size aerator. The main contents of this paper are followed:Through the pilot study, change the different ridge slope after slope and different stream flow, and make comparative analysis of the characteristics of hydraulic factors, such as the flow pattern, pressure, the distribution of the number of the flow cavitaion and aeration cavity characteristics after aeration in the sudden Programs and sudden falls in the size or sudden enlargement and aerator body;This paper will adopt the combination of experimental research and numeG KE model of two-phase flow using VOF method with water vapor turbulent flow, using the geometric reconstruction of cell Water vapor near the interface type for the interpolation with the coupling velocity and pressure using PISO algorithm. Use the non-approximation algorithm for unsteady flow stable solution of unsteady flow to do the three-dimensional numerical simulation of two-phase flow of water vapor from Program one to Program six, with the simulation range from the upper reservoir to flip bucket exports. And then comparatively analyze the characteristics of hydraulic factors, such as the flow state, the water line, flow field, time-average pressure, the distribution of the number of the flow cavitaion and aeration cavity characteristics; Apply the Eulerian model and pressure-Phase velocity correction method to simulate the flow, with the momentum equations Second order upwind discretization method for post-aerator aeration, and make comparative analysis of the effectiveness of aeration and ventilation properties from program one to program six. Simultaneously, based on previous experimental results of test, this research will make three kinds of numerical calculation of the bubbles with three diameters, D=0.5mm, D=1.0mm and D=1.5mm, in order to explore the influence of different bubble diameters on the results of the calculation.