Research On Cavitation And Noise Of Hydraulic Cone Throttle Valve In External Flow Working Condition

Hydraulic cone valve is a typical kind of hydraulic valve. As an important basic element for hydraulic drive and control technology, it has the advantages of good sealing, high surge current and great anti-pollution ability. It is commonly used as throttle valve, cartridge valve, check valve and relief valve. However, the fluid flow of a working hydraulic cone valve is complex. Its structure determines that cavitation is generated inevitably when it works, which causes fluid noise and affects the operation life and reliability of a hydraulic cone valve. Thus, it is of great importance to study the cavitation and noise issue of a hydraulic cone valve to increase the valve’s performance.Hydraulic cone valve is a typical kind of hydraulic valve. As an important basic element for hydraulic drive and control technology, it has the advantages of good sealing, high surge current and great anti-pollution ability. It is commonly used as throttle valve, cartridge valve, check valve and relief valve. However, the fluid flow of a working hydraulic cone valve is complex. Its structure determines that cavitation is generated inevitably when it works, which causes fluid noise and affects the operation life and reliability of a hydraulic cone valve. Thus, it is of great importance to study the cavitation and noise issue of a hydraulic cone valve to increase the valve’s performance.There are many different kinds of hydraulic cone valves. This dissertation discusses two most common ones, cartridge hydraulic cone throttle valve and pipe hydraulic cone throttle valve. The flow field numerical simulation method is used from the perspective of Computational Fluid Dynamics, and the main factors are analyzed of affecting the cavitation and noise intensity of the hydraulic cone throttle valve,including the core geometric parameters and port boundary conditions, to seek a method to decrease or suppress the cavitation and reduce noise. Meanwhile, the cavitation visualization experiment and the noise test of pipe hydraulic cone throttle valve are conducted.Firstly, the basic model, the turbulence model and the cavitation model used for numerical simulation are presented, and the cavitation mechanism and the fluid noise theory are introduced.Secondly, the flow field of cartridge hydraulic cone throttle valve in external flow working condition is studied, a 3D-model is built and grid is divided based on the valve’s structure and parameter. As for the cavitation at the port of the cartridge hydraulic cone throttle valve, FLUENT, the CFD software, is used to perform the numerical simulation of the port flow field of the cartridge hydraulic cone throttle valve.The gas phase distribution, the gas volume rate and the noise level are predicted whencavitation is caused, and the effects of valve opening, valve core angle, core throttling form and number, inlet speed and outlet pressure on the port cavitation and noise of cartridge hydraulic cone throttle valve are investigated.Thirdly, the numerical simulation research on the flow field in the external flow working condition of pipe hydraulic cone throttle valve has been done. The flow field distribution of different inlet velocity, outlet pressure, opening size and core throttling structure is achieved, and the factors for the cavitation intensity and noise level of pipe hydraulic cone throttle valve are analyzed.Lastly, based on the above research, the experiment of the external flow working condition of pipe hydraulic cone throttle valve is performed, in which a model valve made of transparent organic glass is used to observe the cavitation of a throttle valve.Compared the simulation result to the experiment result, the gas volume distribution map obtained from numerical simulation matches the cavitation area and cavitation intensity obtained from the experiment, and the noise changes from numerical simulation show an agreement with the data by experiment. The result indicates that the model and method used for the numerical simulation is logical.