Under The Condition Of Unsteady Flow Submerged Jet Characteristic Numerical Simulation Research

The submerged jet is an important type of fluid motion and it widely exists in practical engineering including submerged jet energy dissipation of water cushion pool,water conveyance system of all kinds of locks,the use of submerged jet and cleaning materials,etc..But in the submerged jet,especially on the conditions of unsteady flow,the fluid motion state is complex.The influence factors are many.The characteristic of submerged jet is not clear,it is significantly important to deeply research properties of jet flow of unsteady flow and also it can also help to solve practical problems in engineering.The aim of this paper is to study properties of the submerged jet flow on the unsteady flow conditions.The characteristics of jet and Single-hole mathematical model were constructed.Compared computing values by modeling to situ values of Wall jet of rectangular shaped holes of Pany and Rajaratnam,the accuracy and rationality of the established mathematical model were verified.By the verification,the numerical simulation results agreed well with the measured values of the wall jet,and the relative error was control less than 2%,which indicated that the simulated and measured values were in good agreement with the measured values.In verifying the accuracy of mathematical model and the rationality of the premise,calculated by Fluent software and the turbulent flow,gas-liquid two-phase flow VOF simulation of free surface,using RNG turbulence model for numerical simulation,select the width of the hole pitch and actual model,in consideration of the calculation and analysis of the different branch number,different velocity,different between the hole spacing and different incident hole the submerged water depth,the main results are as follows:(1)According to single hole simulation calculation,and analyses the calculation results,the working condition of the orifice discharge without sill near the hole of the flow field structure is divided into jet core layer,shear zone,near boundary shear layer,the upper low velocity zone and so on four parts.Different jet velocity of the flow field structure will produce certain effects,the greater the flow velocity,the jet core region,the smaller the corresponding boundary layer shear zone.(2)According to the double hole simulation,and analyses the calculation results,the double branch hole jet flow,the interaction between water flow,the entrance of the jet interaction flow field,fluid mixing obviously,the flow velocity and the distancefrom the bottom of the jet core region section height are fourth power relations.(3)Through the calculation and analysis of different branch hole spacing model,the influence on fluid structure there is a big sink hole spacing,the hole spacing,the greater the interaction two fluid is smaller,reflect on the fluid velocity,sectional velocity distribution is uneven,effect the water tank of water;The smaller the hole spacing,the strength of the interaction between the two fluid,the fluid kinetic energy dissipation,the greater the fluid flow velocity tends to smooth the shorter the time.Indicate that as far as possible in the hole jet with small spacing arrangement jet,which is beneficial to ensure stability on the surface of the liquid flow.(4)Under different flow conditions,the orifice discharge jet mainstream area of the flow field distribution of the vertical section is similar to that maximum velocity variation trend of each section along the stream direction also has a good similarity.