| The non-full-circle opening slide valve,that is,the throttle valve,is one of the basic structures of the hydraulic valve,and is widely used in proportional valves and servo valves.Different throttle grooves can be used to obtain different flow,pressure and hydraulic characteristics,which have a great influence on the performance of the hydraulic valve.The U-shaped throttle groove is the most common structure in the non-full-circumferential open-slide valve.One of the forms,the processing is simple,the production is convenient,and because of its own large hydraulic radius and anti-blocking ability,it can easily obtain a small stable flow value,and has a wide flow adjustment range.Moreover,the U-shaped throttle groove has a small gradient of the flow area and is easy to handle,and can be finely adjusted.In this thesis,the CFD(Computational Fluid Dynamics)software FLUENT is used to simulate the U-shaped throttle slide valve,and its various characteristics are studied in detail.Firstly,based on the characteristics of pressure distribution of U-shaped throttling groove,the formula of valve port area of U-shaped throttling groove is derived according to the principle of equivalent valve port over-flow area,and the calculation program is written by MATLAB software;The size of the brand’s U-shaped choke slide valve is calculated to calculate the minimum over-flow area.It is found that when the throttle groove depth H does not exceed 1.5 mm and the throttle groove width B does not exceed 2.0 mm,the critical opening degree can be obtained.Secondly,with the help of SolidWorks,a total of nine computational fluid regions of U-shaped throttling slots with different parameters are established.Pretreatment by CFD software ICEM CFD again to unstructured hexahedral grid computing area,and imported into FLUENT software,setting boundary conditions are needed for the operation and physical model,set the middle area and throttling valve core fluid tank fluid field for sliding grid,the axial movement over time,when it is concluded that the different valve opening of pressure and velocity contours,and collect the maximum velocity,maximum pressure,minimum pressure,mass flow at the inlet and outlet.The influence of the depth and width of the u-shaped throttle groove on thepressure distribution,velocity distribution,flow characteristics and jet angle is analyzed by comparing the velocity cloud diagram and pressure cloud diagram and the collected data.The following conclusions are drawn:(1)when the valve opening is between 1.5 mm and 2.0 mm,the U-shaped throttle groove slide valve generates the maximum velocity at the valve opening;(2)groove width B and groove depth H have an impact on the oil flowing through the throttling groove,and the mass flow rate will change in direct proportion to the groove width B and groove depth H,but the change of groove depth H has a greater impact on the flow rate than the change of groove depth B.(3)U throttle opening slot jet angle of slide valve and the traditional the week of the slide valve jet angles ? =69° constant,U-shaped throttling groove of the slide valve jet angle decreases as the opening of the valve port and decreases first,and after the valve fully open,jet angle and the week opening valve and the traditional jet angle is equal to about 69 °.The data and conclusions in this paper are of great significance to the optimization design and performance improvement of the hydraulic valve structure. |
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