The Velocity Characteristics Of Annular Water Formed By The Smooth-running Piped Car With Various Loading Capacities

In order to meet the development of modern green logistics industry, multiple transportation modes with high efficiency and energy saving potential are being developing and applying based on the actual requirement. Relying on the National Natural Science Foundation of China(Grant No. 51109155 and 51179116), the Shanxi Province Science Foundation(Grant No. 2015011067) and the Graduate Student Innovation Project(Grant No. S2014108), this thesis was researched. The velocity distribution of annular water formed by the smooth-running piped car with various loading capacities was researched by the experimental investigation integrated with theoretical analysis. The results were as follows:(1)With the increasing of loading capacities, the speed of piped car with same model decreased, when running in the horizontal piped. Under the experimental conditions of setting testing flow in 40m3/s and changing the loading capacities from 0 kg to 0.5 kg by 0.1kg, the speed of piped car(L×D=150mm×60mm) reduced sharply(-1.09m/(s ·kg)), the speed of piped car(L×D=100mm×70mm) reduced slowly(-0.74m/(s ·kg)).(2)With the same loading capacities, the distribution of axial velocity in the moving boundary annular area formed by the piped car with different model was no longer maintained concentric distribution. But there were still some similar characteristics in the distribution of axial velocity: compared with the middle test section of the piped car, the axial velocity gradient of annular water in the front and latter test section of the piped car were bigger; the axial velocities of annular water had great relationship with the diameter of piped car, the axial velocities of annular water formed by the piped car(D=60mm) were almost greater than the average velocity of the pipeline water without piped car, while the change trend of these velocities was on the contrary with the piped car(D=70mm); the axial velocities of annular water formed by the piped car(L×D=150mm×70mm和 L×D=150mm×60mm) increased at first then decreased, along the radial in the annular cross section, and the maximum value nearly appeared the central ring gap.(3)With the piped car(L×D=150mm×70mm) as an example, the axial velocity distribution of annular water was relatively stable in the middle test section of the piped car, where the minimum velocity appeared near the pipewall, while the location of the maximum velocity was floated in the center ring gap along with the various loading capacities of piped car. There were some obviously gradient zones of the axial velocity in the front and latter test sections of the piped car. The axial velocity gradient in the latter test section of piped car was biggest(η=0.11), which in the middle test section was smallest(η=0.09). The effects on the axial velocity gradient in different sections were not obviously by the various loading capacities of piped car. With the increasing of loading capacities, the relative size relations between the speed of piped car and the average velocity of annular water was changed at M=0.2kg, where the relative speed value decreased first then increased.(4)With the piped car(L×D=150mm×70mm) as an example, the speed value of radial velocities and circumferential velocities of annular water significantly reduced compared with axial velocities. The speed direction of radial velocities mostly pointed to the pipe axis and the speed direction of circumferential velocities were mostly in a counterclockwise direction along the circle. The effect on the circumferential and the radial velocity distribution were not obvious by the various loading capacities of piped car.(5)With the piped car(L×D=150mm×70mm) as an example, the axial average velocity in the middle test section was increased first then tend to the volatility with the increasing of loading capacities. The axial average velocity value was approximate calculated by integral and software, whose relative errors were within 0.1%. The trends of radial and circumferential average velocity were under a small scale fluctuation with the increasing of loading capacities. The two-dimensional resultant velocity values were concentrated in 0m/s ~ 0.06 m/s mainly. The values ratio between resultant velocity and axial velocity were above 0.99.(6)With the piped car(L×D=150mm×70mm) as an example, compared the horizontal velocity and vertical velocity fluctuation intensity, the axial velocity fluctuation intensity of annular water were always larger under the same test conditions. With the increasing of loading capacities,the local fluctuation intensity gradient of axial velocity increased obviously,while the whole fluctuation intensity gradient almost invariant. With the increasing of loading capacities of piped car, the fluctuation intensity distribution of horizontal velocity and vertical velocity were relatively uniform with a small oscillation. Under the same conditions, the fluctuation intensity distribution of axial velocity showed a trend of increase as the increase of piped car’s diameter or the decreases of piped car’s length. But the pulsation intensity of horizontal velocity and vertical velocity still remained stable.These analysis results could not only provide a theoretical basis for the further research on the concentric annular gap flow in dynamic boundary theory, but also could promote the research and engineering applications of Tube-Contained raw material piped hydraulic transportation technology.