Study On The Sound Characteristics Of Rod Vibration Under Turbulence

In the modern society,the problem of water pollution is more and more serious,so the development of sewage treatment device is very important.At first,the researchers used electric sewage treatment,the difficulty is dealing with a large flow of liquid,however,the fluid power generator has the advantages of simple structure,low cost,large capacity,the operation is convenient and durable and so on,to deal with large flow of water is very good. At present,the most commonly used fluid power type sewage treatment devices have the perforated plate,the venturi tube and the reed whistle,they each have their own advantages and disadvantages.Based on the above reasons tuburlence generator is presented,which mainly processes acoustic intensity by the rod vibration,so it is very important to study the sound characteristics of the rod vibration under the effects of the turbulence.In this paper,the sound characteristics of the rod vibration was studied by using two methods of numerical simulation and experiment under the effects of the turbulence.Firstly,on fluid power generator,the progress of the research approaches and results are introduced at domestic and foreign;secondly,this article introduces the fluid solid coupling theory and numerical calculation method,and the numerical calculation of fluid solid coupling interface form of information transmission are described;the new version of the finite element software ANSYS Workbench and the numerical simulation method of bidirectional fluid-structure interaction are adopted to simulate the flow field and the rod vibration characteristic,in order to explore the effect of operation parameters and structure parameters on the flow field and the rod vibration characteristic;finally,the sound characteristic of the rod vibration under the effect of turbulence has carried on the simple research. Main works are as follows:1.The fluid-structure coupling theory and numerical calculation method are introduced,and combining the characteristics of the turbulence acoustic generator were analyzed,the appropriate numerical method is chosen which is numerical method of the bidirectional fluid-structure coupling.2.The numerical calculation process of the bidirectional fluid-structure interaction are introduced,and the simulation results are analyzed.The simulation results show that if the flow field distribution is symmetrical,the four rod vibration pace and amplitude are consistent,if the flow field is asymmetrical,the four bar vibration is not the same pace and amplitude,the flow field asymmetry is mainly caused by the negative pressure region which appears in the pressure field.3.Using the numerical simulation method of the bidirectional fluid-structure interaction studies the operating parameters and the structure parameters of turbulent sounder on the influence of the flow field,the liquid velocity,turbulent kinetic energy and the local absolute pressure of the liquid are calculated,then the characteristics of the flow field are analyzed.The simulation results show that:(l)for a certain size of turbulent sounder,improving the inlet pressure can make the liquid velocity and the turbulent kinetic energy increased,the local absolute pressure of the liquid decreased,then improving the inlet pressure can enhance the turbulence intensity of the flow field.(2)when the inlet pressure and other structural parameters remain unchanged,increasing the nozzle throat diameter can make the liquid velocity and the turbulent kinetic energy increased,the local absolute pressure of the liquid decreased,it is helpful to enhance the intensity of turbulence.(3)when the inlet pressure and other structural parameters remain unchanged, the nozzle to the barrier distance has an effect on the flow field and there is a best value.(4)when the inlet pressure is constant, changing the nozzle pipe length,with the increasing of pipe length,the intensity of turbulence is enhanced. The results of this study hope to provide a certain reference value for structural optimization to turbulent acoustic generator.4.Using the numerical simulation method of the bidirectional fluid-structure interaction studies the operating parameters and the structure parameters of turbulent sounder on the influence of the rod vibration characteristic,the average amplitude of the overall rod and the change rule of the four rod variation displacement with time are calculated,then the vibration characteristics is analyzed. The simulation results show that:(1)for a certain size of the turbulent acoustic generator,with the increasing of the inlet pressure,the average amplitude of the overall rod is increasing,then we can launch that improving of the inlet pressure is helpful to obtain a higher sound intensity,four rod vibration pace with inlet pressure is also different.(2)when the inlet pressure and other structural parameters remain unchanged,increasing the nozzle throat diameter,the average amplitude of the overall rod is increasing,then we can launch that increasing of the nozzle throat is helpful to obtain a higher sound intensity,when the throat diameter is 8mm,the four rod vibration displacement situation is good.(3)when the inlet pressure and other structural parameters remain unchanged,the nozzle to the barrier distance has an effect on the rod vibration characteristic and has an optimum value.(4)when the inlet pressure is constant,increasing the nozzle pipe length,the average amplitude of the overall rod is increasing,when the nozzle pipe length is5mm,the vibration is most close to the equilibrium position.The results of this study hope to provide a certain reference value for structural optimization to turbulent acoustic generator.5.Through the experiment studies that the different inlet pressure influence on the sound characteristics of the rod vibration under the action of the turbulence.The experimental results show that:with the improving of inlet pressure,the main sound frequency is reduction,sound pressure level increases constantly,so as to verify the reliability of the simulation results.