| The control valve is widely used in various fields of industrial production as a control element of piping system.Due to the working principle of control valve is throttling,so it will produce strong noise in the working process of the control valve.Noise pollution is one of the major sources of environmental pollution,the harm is very great on human health and production safety.The following research work has been carried on in this paper,aiming at the noise problem of a cage type control valve for some power device:The steady flow field of control valve were simulated under different conditions,the pressure,velocity and turbulent kinetic energy distribution characteristics of the control valve internal flow field were got.Based on this,the reason of the fluid motion instability and noise of the control valve were preliminary determined.On the basis of steady state flow field calculation,the transient analysis of the valve flow field is carried on based on the large eddy simulation.Based on the transient characteristics of control valve flow field,the simulation of the aerodynamic noise radiated acoustic field was carried on.The reliability of the simulation analysis process is verified by comparing the simulation data with experimental data.The simulation calculation of the structure mode and acoustic mode of control valve were carried on from the perspective of resonance.And the structure vibration noise was calculate based on the structure mode,the structure acoustic coupling problem of control is studied.In view of the problem of control valve internal structure causes unstable flow field and noise,the optimization measures of control valve structure are put forward.The flow field and acoustic field of optimized control valve is calculated to verify the effectiveness of the optimization measures.According to the work in this paper,we find that the maximum fluid velocity is at throttle channel outside of the valve cage,but the fluid velocity distribution is uniform,so the turbulent kinetic energy is small;The flow velocity gradient,the turbulent kinetic energy and and the flow noise are largest at the intermediate throttling channel of valve cage;In the middle of the valve cavity the rectifier makes the fluid velocity direction change,and causes the valve cavity area produce larger quantity and large size whirlpool;In the high frequency,noise in the valve has obvious characteristics of broadband,sound pressure level decreases with the increase of frequency.By improving the structure which causes the aerodynamic noise of the control valve,makes the noise level of control valve reduces about 10%,and the advantage noise frequency in high frequency region moves to the low frequency region.The flow rate of optimization valve is lower than the original valve,but the range is very small,it does not affect the work performance of control valve. |
