Research On The Velocity Characteristics Of Spiral Flow In The Same Double Carriages Under Different Spacing Conditions

With the rapid development of our country's economy,people's living standards have improved significantly.The traditional transportation mode(highway,railway,aviation,waterway)bears more and more transportation pressure,and when the flow of people or logistics reaches the peak,the traditional way of transportation is difficult to meet the needs of people and economic development.Therefore,we need to find more and economical and environmentally friendly modes of transportation to meet the growing needs of people.However,tube feeding pipe hydraulic transportation technology is based on this situation.As a new transportation mode of energy saving and environmental protection,tube feeding pipe hydraulic transportation technology will greatly change the existing traffic and transportation status in the near future.This paper is in the National Natural Science Foundation of China,"Pipeline Train Hydraulic Transport Energy Research(51179116)","Pipeline Slot Spiral Flow Hydraulic Characteristics Study(51109155)"and Shanxi Provincial Youth Science and Technology Research Fund"Characteristics of flow around a cylinder in a straight finite tube region(201701D221137)".Based on the method of theoretical analysis and experiment,research on the velocity characteristics of spiral flow in the same double carriages under different spacing conditions.In addition,the impact of flow rate and carriage type on the flow field in the workshop was also studied,and the following conclusions were reached:(1)In the case of the same flow rate and type of carriage,the uniformity of the axial flow velocity distribution on the test section under the same inter-carriage distance is proportional to the distance between the test section and the pipeline behind the carriage.That is,the cross-sectional axial velocity distribution is more and more disordered in the sections closer to the rear-carriage distance,and the axial velocity distribution on the section farther from the rear carriage is more uniform.Only the flow velocity fluctuations are relatively large near the tube wall.In addition,from section 1 to section 5,the flow rate showed a decreasing trend;With the increase of inter-carriage distance,the fluctuation of flow velocity in the same section becomes smaller and smaller.When the distance is large enough,the flow velocity will tend to be stable and restore the original concentric annular distribution state.When the distance is less than 50cm,the axial flow velocity increases first and then decreases with the increase of the measuring ring radius from the center of the pipe to the pipe wall.When the inter-carriage distance is 90cm,the axial flow velocity is basically decreasing from the center of the pipe to the pipe wall,which is in line with the concentric annular distribution of the flow velocity when the pipe is without a carriage.(2)The radial flow velocity on the same test section decreases as the inter-carriage distance increases.Under the same inter-carriage distance,the radial velocity of the same test section is larger in the direction away from the center of the pipe,and the direction to the center of the pipe is smaller.The radial velocity of the 1#test section is the largest,the radial velocity of the 5#test section is the smallest,and the radial velocity of the test section is inversely proportional to the distance from the rear of the carriage.In the direction of the polar axis,the radial velocity shows a trend of increasing first and then decreasing with the increase of the radius of the measuring ring.The radial velocity is wavy in the direction of the measuring ring.(3)The circumferential flow velocity on the same test section also decreases with the increase of the inter-carriage distance;in the case of the same inter-carriage distance,the circumferential velocity of the test section closer to the rear of the carriage is larger,and the distribution of circumferential velocity of the cross-section is more disordered.The maximum value of the circumferential velocity of the test section is often located between the center of the circle and the wall of the tube,about half the radius of the tube,and the minimum value of the circumferential flow velocity is usually located near the wall of the tube.(4)when the flow rate is 30m~3/h,the best distance between the two carriages is 90cm.(5)At the same flow rate,the average axial flow velocity and axial flow velocity gradient along the test section of the workshop tend to decrease along the course.That is,the average axial flow velocity and axial flow velocity gradient of the 1#test section are the largest,and the axial average flow velocity and axial flow velocity gradient of the 5#test section are the minimum.The axial average flow velocity of the same test section is proportional to the flow rate.And the larger the flow,the more uniform the velocity of the axial flow is along the polar axis and the direction of the ring.(6)Different models of carriage are all with a large gradient of axial flow velocity on the 1#test section,and then the axial flow velocity gradient on the test section tends to be gentle;The influence of the diameter of the carriage on the test section flow rate in the workshop is greater than the length of the carriage.When the diameter of the carriages is small,the axial flow velocity distribution of the test section in the workshop is more uniform.This paper not only enriches and perfects the theory of tube feeding pipe hydraulic transportation,but also speeds up the application process of tube feeding pipe hydraulic transportation.