The Research Of Vertical Vortex In Hydraulic Intakes

The vertical vortex is a normal hydraulic phenomenon before intakes of hydraulic structure such as diversion pipeline of hydraulic power station, spillway, diversion tunnel, high-power water pump, canal for water conveyance. The existence of vertical vortex will decrease the discharge ability, influence the efficiency of hydraulic turbine generator unit, increase the fluctuation of water and absorb the floating substances. Those can endanger seriously hydraulic structure or hydraulic equipment and impose huge economic loss. However, due to its complexity, breakthrough in vertical vortex has not been made by far. The research result cannot satisfy the need of engineering design.In this paper, according to practical liquid differential equation ,allowing for moving rule and characteristic of moving field of vertical vortex , simplifying N-S equation, I have studied the discipline of condition, velocity and pressure of vertical vortex and analyzed some theory solutions such as plain vortex solution and solution in axial direction.The observed data of vertical vortex model test and prototype are analyzed. The study of scale effect of vertical-axial vortex is a little novel. Many rules of model movement of vertical-axial have been discussed. A little model in laboratory was designed for experiment. This article analyzed calculating means of critical submergence depth, summed up developing process of vertical vortex and studied effect on discharge of orifice by vertical vortex.In the study of vertical vortex, VOF method of two phases of water and air and K-ε model have been applied. Three-dimensional moving field is numerically simulated first in this paper and characteristic of the whole vortex moving field has been acquired. The moving discipline of vertical vortex has been simulated more factually by contrast with previous study. The developing process of free face of vertical-axial vortex has been analyzed. Moving shape of vertical vortex has been summed up. Inspirations of vortex, pressure of moving field and distributing of velocity have been studied. With two different flux and circulation moving shape of vertical vortex has been compared. At the same time the effect of submergence, outflow and boundary condition of intake and moving of vertical vortex have been analyzed.Model test and numerical simulation have combined with practical power station. Through model test the moving shape of vertical-axial vortex has been analyzed and the relationship of flux, submergence with exit of vertical-axial vortex. In numerical simulation, practical landform data and set up horn-shape intake and air vent pipe are adopted. The moving shape of vortex has been simulated and the result of model test accords with simulation result well.