| This article was completed in cooperation with Anhui Tongdu Flow Technology Co.,Ltd.The experiments involved in this article were performed at the No.3 Waterworks in Ruzhou City,Henan Province.Hydraulic machinery is the most common in people's daily life,industrial production,and transportation.At this stage,hydraulic machinery is gradually developing in the direction of large-scale,high-speed,high-power and high-performance.Piston-type flow control valve can easily regulate flow,it is widely used in water conservancy systems due to its pressure regulation,venting and energy dissipation.However,in practice,due to the lack of large-diameter valve flow resistance coefficient and flow characteristics test and test devices across the country,the design flow of large-diameter piston flow control valves is difficult to meet the expectations,which causes the valve flow cannot be accurately selected.If the selection is too large,it will cause the control valve to work in a small opening,which is prone to cavitation,high noise and other problems,which will affect the stability of the valve and pipeline system.In this paper,the following research work has been done on the above issues.(1)According to the two-dimensional drawing of the piston flow regulating valve,the three-dimensional model is established by using SolidWorks software.Based on computational fluid dynamics(CFD),the surface roughness in actual processing was converted into equivalent roughness that can be input in ANSYS CFX.The effects of smoothness and different surface roughness levels on the flow characteristics of piston flow control valves were studied,which provided conditions for the subsequent accurate calculation of turbulent flow field and cavitation in the valve.(2)According to the technical requirements of the cooperative enterprise,based on the computational fluid dynamics(CFD)method,the internal flow field of the piston flow control valve at different opening degrees is simulated,and the pressure,velocity,and turbulent kinetic energy at different opening degrees was obtained and calculate the cavitation critical value of each type of valve.According to the analysis results to make corresponding structural improvements,then designing a new structure of the piston flow control valve to improve the valve's anti-cavitation performance.(3)Based on the immersion entity method in ANSYS CFX,the dynamic characteristics of the opening process of the piston flow control valve are simulated,the three-dimensional flow field from the closing to the full opening process is calculated,and the distribution law of velocity,pressure and turbulent kinetic energy in the flow field in the valve domain is analyzed.Use the CEL language to explore the variety law of the valve inlet,center,and outlet monitoring points with the opening degree.Analyze the change rule of the pressure on each monitoring surface of the moving component in the valve with the opening degree to provide a reference for improving the stability of the valve and further research and development.(4)The formation mechanism of the flow noise in the valve and the type of the flow noise of the valve were studied,and the standard of flow noise prediction was investigated.Based on the calculation of the flow coefficient by CFD,the IEC60534-8-4-2005 standard is used to predict the value of the liquid flow noise at 1 meter outside the valve under specific working conditions.The precision free field microphone,multi-channel vibration noise test collector and PC were used to test the noise value at the throttle position of the outlet section of the piston type flow regulating valve at 1 meter to verify the accuracy of the calculation method of the predicted noise value.Through the above research,it provides a reference for improving the operation stability and reliability of the large-diameter piston flow regulating valve,and has clear guiding significance for design optimization and reasonable selection. |
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