| As one of the most commonly used industrial raw materials,high viscous liquids are widely used in aerospace,chemical industry,lubrication and petroleum fields.For example,high viscous resin injection parts are used more and more in a diversified manufacturing system because of their corrosion resistance,high temperature resistance,insulation,light weight and low cost.However,in the process of manufacturing high viscous fluids with vacuum injection moulding machine,it is found that the application effect of the existing cut-off valves on the market is very poor.Therefore,the valve and pipeline system suitable for high viscosity fluid has gradually become a research hotspot of scholars.In this thesis,a globe valve is designed according to the characteristics of high viscosity fl uid,and the system composed of globe valve and pipeline is studied.Referring to the valve design manual for a preliminary design of the high viscosity fluid shutoff valve structure.By establishing a three-dimensional model,using FLUENT software simulation research method,based on the overcurrent resistance as the judgment basis,the structure of the shut-off valve is optimized.At the same time,the shut-off valve flow test bench was built,and the correctness of the numerical simulation analysis was verified by the corresponding experimental test.In order to study the flow field distribution during the closing process of the shut-off valve,dynamic mesh technology and external custom function(UDF)program are used to realize the dynamic simulation of the flow field in the shut-off valve,and several reductions are obtained.The conclusion of the over-flow resistance of the small stop valve further optimizes the structure of the shut-off valve and improves the over-current performance,providing a reliable theoretical basis for the design and selection of high-viscosity fluid valves.In the actual application process,the shut-off valve will bring a fluid-solid coupling effect similar to the water hammer effect to the valve piping system when it is quickly closed,which affects the normal operation of the valve piping system.This thesis draws on the advantages of many fluid-solid coupling models of pipelines,and establishes a new fluid-solid coupling mathematical model.Taking the high-viscosity fluid three-dimensional bending pipe as an example,the mathematical model,finite element simulation and experimental measurement are compared and analyzed.Analysis of various factors such as difficulty,operational flexibility and cost,it is concluded that the finite element analysis method is more conducive to the study of the fluid-solid coupling process of the shut-off valve and piping system for high viscosity fluids.On this basis,ANSYS software was used to simulate and analyze the influence of different pipeline structures on the dynamic characteristics of the valve piping system under the action of the valve closing quickly.Through analysis,it is concluded that the effect of closing the valve in different motion modes has different effects on the stability of the system,and the closing mode that is most beneficial to the stability of the system is sinusoidal acceleration;the support position of the valve piping system should be set with reference to the deformation position of the system.The laws of natural frequency and deformation of the system are different under different support modes;changing the wall thickness of the pipeline has little effect on the natural frequency of the system,and the fluid-solid coupling effect is weakening. |
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