Study On Force Characteristics And Distribution Pattern Of Flow Field In Tube Of Pigging Process

Pipeline transportation is one of the four major material transportation approaches,mainly used for the transport of petroleum crude oil,refined oil product and the natural gas.The conveying pipeline cleaning(hereinafter referred to as the pipeline cleaning)is an indispensable organic constituent of pipeline transportation.With the development of oil industry,pipeline cleaning technology is receiving increasingly more attention.Cleaning the pipe with pipe cleaner is the major approach for the pipe cleaning technology.However,there are safety problems,including the pipe bracket falling off from the pipe support,pipe displacement,and plastic deformation resulted from the collision between some angle fittings with the pipe support.In terms of these problems,this paper made use of the calculation software such as Matlab,Olga,ANSYS-Fluent,and Autopipe to make relevant study.The major content is as follows:To begin with,on the basis of the Matlab calculation software,it used the momentum equation to calculate the influences of the change of momentum on the pipe cleaning system,analyzed the applicability of the pipe cleaner;then,it studied the influences of different flows,different operation pressures and different gas content ratios on the pipe cleaning;furthermore,under the turbulence status,it adopted the Fluent3d double-precision solvers to make the numerical simulation through the flow field variation;at last,in terms of the loading generated by the serious turbulence of the internal flow(mainly shown as the plug flow loading),it calculated the water attack and slug flow loading under three working conditions of " fluid over fluid","air over hydraulic" and "recovered air source" through analog computation with the Autopipe.The simulation study results shows that major reasons for the pipe bracket falling off,pipe angle fittings suffering from the plastic deformation are as follows:when the N2 serves as the gas source to make the over hydraulic process pipe cleaning with pipe cleaner for the petroleum pipe beyond the storage,there are problems of unfitted sealing and serious gas leakage between the pipe cleaner with the bend fitting of pipe 1.5DN.After the gas leakage,the flow flied inside the pipe in front of the pipe cleaner becomes more complicated and variable,and the pressure changes rapidly,which leads to the instability of pipe cleaning system.After the recovery of N2 air source,the air column of the pipe system would generate compression and boost pressure during the moving process,which generates huge working force on the bend fitting of the pipe,resulting in the axial displacement and upright jerking of the pipeline system,pipe bracket falling off and the plastic deformation of some bend fittings.