| Pig launching trap,referred to as "launcher",is usually linked together with the long distance pipeline and the station pipeline.The pig launching trap is installed in the beginning of pipeline and is used to launch the pig.Because of the advantages of reasonable structure,reliable working performance and easy installation,it is widely used in long distance and gathering pipeline maintenance work in petroleum,chemical industry and so on,such aspigging dewaxing and descaling,which is the important pipeline accessories ensuring the pipeline construction and the stable operation.When the launching trapis in operation,the vibration is very significant,and the strong vibration of thelaunching trap would cause a great threat to the safe production,such as:rupturing in piping joint,the support loosing and pressure gauge not working properly,the ball tube rupturing and spilling,etc.What's more,the vibration characteristics study of the launching trap is less and is lack systemicat this stage.The vibration source,the reasons of causing vibration,the vibration mechanism and corresponding control measures of the launching trap were studied in his paper,at the same time,the experiment testing and numerical simulation methodswere determined.For the fluid system,the flow control equationtheory and the turbulence model were studied,and the boundary conditionsare consistent with the actual working condition,and the fluid-structure coupling mathematical model were analyzed.The internal flow field change of the launching trap was analyzed in fluent software.When the transmission medium is the gas and liquid,the flow field change of the launching trap was studied,and the affect of the structure parameters(the by-pass pipe diameter and valve opening)and fluid parameters(pressure and flow velocity)on flow field were analyzed.And then explorethe distribution regularity of pressure field,velocity field and turbulence intensity under two kinds of working condition.The vibration characteristic of the launching trap was analyzed in the Ansys Workbench software.The inherent frequency and vibration modelunder the working conditions of without mutual coupling and fluid-structure coupling(gas-solid coupling and liquid-solid coupling)were analyzed,and the affect of structure parameters(ball wall thickness,by-pass pipe diameters)and fluid parameters(flow velocity and pressure)on inherent frequencies and total deformation of the launching trap were analyzed.For the vibration test ofthe launching trap in the gas transmission station,the data was analyzed and processed by system software,and it is found that the inherent frequency average of the launching trapis 41.4889 Hz,and the value is very close with the result calculating by the finite element modal.Finally,according to the vibration analysis and test of the launching trap,three kinds of corresponding decreasing vibration methods were putforward,and the modal and gas and solid coupling were analyzed for the three different kinds of methods,and the decreasing vibration effect was compared analysis with the original structure mode,and it is found that increasing the tubing diameter and elbow diameter can reduce the vibration intensity of the launching trap effectively.The vibration characteristic of the launching trap was studied by the numerical calculation and experiment in this paper,which provides the reference for fielduse and structure optimization. |
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