Study On Vorticity Characteristic Of Intersecting Cylindrical Sysytem In Pressure Pipeline

As a new type of transport theory,the hydraulic transport theory of the cylinder loading pipe is regarded as a new type of transport theory.This transportation mode is a new solid-liquid two-phase flow transportation mode of large mass through the modification and improvement of the traditional pipeline transportation mode.It not only has the characteristics of low transportation cost and high transportation efficiency,but also its special mode of transportation-pipeline vehicle transportation,which greatly enriches the selection of transportation materials.Due to the existence of the pipeline vehicle this special carrier container,making in the transport process to avoid the material and transport media direct contact,prevent the material and transport media related reaction,reduce the loss of material in transport,save the material after receiving the dehydration and other related complex procedures.Therefore,the research on the pipeline vehicle and its surrounding flow field is the only way to promote the transport theory to be applied to practice as soon as possible.This paper takes into account that the structure of the pipeline vehicle belongs to an intersection type cylindrical system and according to the characteristics of the structure of the pipeline vehicle,combined with the National Natural Science Foundation of China "Study on energy consumption of hydraulic transportation of pipeline vehicle(51179116)",the numerical simulation of the vorticity field around the intersection cylinder system is carried out by using Fulent software and the physical test verification is carried out.By changing the size of main cylinder and the flow rate in the pipeline,the vorticity field characteristics change with different parameters is simulated and calculated.The following conclusions are summarized through analysis:1.The results calculated by numerical simulation are compared with the results of physical experiments in related literature,and it is found that the relative error between the simulation results and the experimental results is less than 4.6%,which proves that the simulation method is feasible.2.The vorticity field of intersecting cylindrical system is centrally symmetric on the whole,and the vorticity is concentrated near the support legs and the outer wall of the cylindrical system and the inner wall of the pipeline.The vorticity concentration region is also the region with the largest velocity gradient in the velocity field.3.The vorticity gradient along the upper and lower walls of the main cylinder is very large,and after leaving the wall,a relatively obvious vorticity zone is formed around both sides of the flow field behind the column.The difference lies in that the vorticity zone behind the lower leg is not obvious due to the presence of the leg.4.Due to the influence of the three legs,the vorticity distribution presents an annular array distribution with an included angle of 120°.The vorticity is mainly concentrated near the three legs and diffuses circumferentially to form a circular vorticity belt.5.When the size of the column remains unchanged,the vorticity value of the vortex field behind the column increases as the flow rate increases,and the influence range of the vorticity field begins to extend to the downstream.At the same flow rate,with the increase of the diameter of the main cylinder,the vorticity value increases as a whole,the vorticity distribution in the center region of the pipeline decreases,and the whole vorticity field presents a ring distribution.With the increase of the length of the main cylinder of the column,the vorticity value also increased,the overall form of the vorticity distribution in the flow field behind the column does not change much,but the area in which the vorticity gradient increases obviously increases.6.For the vorticity field after the legs,under the condition of constant flow,the vorticity value decreases with the increase of the distance from the legs.As the flow rate increases,the vorticity value also increases,but this law is only applicable within a certain distance behind the legs.As the distance from the legs increases,the vorticity value fluctuates almost within a certain range and is not affected by the flow rate change.When the flow rate is constant,with the increase of the length of the main cylinder,the decreasing range of the vortex decrease region increases.Moreover,the further away from the pipe wall,the more affected the vorticity field is.At the same time,with the increase of vehicle length,the influence length of the descending zone increases from 30 mm to 50 mm along the flow direction,and the increase of vehicle diameter has a similar effect on the vorticity field.