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Dynamics of vertical pipe in deep-ocean mining system

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Journal of Central South University of Technology 2007年第4期14卷 552-556页

作者：禹宏云刘少军 School of Mechanical and Electrical Engineering Central South University

A 3-D geometrical nonlinear model for the entire lift system of 1000-m sea trial system of China Ocean Mineral Resources R&D Association was established with finite element *** model was utilized to analyze the dynamic characteristics of the vertical pipe under the influence of moving velocity,current direction and *** simulation results show that the axial stress is dominant on the vertical pipe,its maximum is located at the pipe top,all stresses are much less than the allowable value of the vertical pipe and joint;the heave motion leads to violent fluctuation of the force and stress,but a period of 8 s is not likely to resonate the present pipe;against the current,0.50 m/s is the suggested moving velocity of the ship and miner,while along the current,the moving velocity can be slightly higher than 0.75 m/s.

关键词： deep-ocean mining dynamics vertical pipe finite element method geometrical nonlinearity

An Investigation on the Void Fraction for upward Gas-Liquid Slug Flow in vertical pipe

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Chinese Journal of Chemical Engineering 2001年第4期9卷 436-440页

作者：夏国栋周芳德胡明胜 CollegeofEnvironmentalandEnergyEngineering BeijingPolytechnicUniversityBeijing100022China StateKeyLaboratoryofMultiphaseFlowinPowerEngineering Xi＇anJiaotongUniversityXi＇an710049China

In order to investigate the influence of the entrance effect on the spatial distribution of phases, the experiments on gas-liquid two-phase slug flow in a vertical pipe of 0.03m ID were carried out by using optical probes and an EKTAPRO 1000 high speed motion analyzer. It demonstrates that the radial profile of slug flow void fraction is parabolic. Influenced by the falling liquid film, the radial profile curve of liquid slug void fraction in the wake region is also parabolic. Since fully turbulent velocity distribution is built up in the developed region,the void fraction profile in this region is the saddle type. At given superficial liquid velocity, the liquid slug void fraction increases with gas velocity. The radial profiles of liquid slug void fraction at different axial locations are all saddle curves, but void fraction is obviously high around the centerline in the entrance region. The nearer the measuring station is from the entrance, the farther the peak location is away from the wall.

关键词： gas-liquid slug flow void fraction vertical pipe

A Comparative Study of Closure Relations for CFD Modelling of Bubbly Flow in a vertical pipe

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Open Journal of Fluid Dynamics 2021年第2期11卷 98-134页

作者： Geoffrey S. Gray Scott J. Ormiston Department of Mechanical Engineering University of Manitoba Winnipeg Canada

Commercial code CFX was used to examine the performance of a two-fluid model to predict the details of upward isothermal bubbly flow of air and water in a vertical pipe. The model equations are volume-averaged Navier-Stokes equations that require closure models for interfacial forces and bubble-induced turbulence effects. Two-equation SST and k-epsilon RANS turbulence models were also used. A parametric study of closure models included both standard options in CFX and previously published novel closure models that were implemented with user-defined functions. The CFD simulations were compared with two cases from the MTLoop experiments by Lucas et al. at the Helmholtz-Zentrum Dresden Rossendorf: one with wall-peak void fraction profile (MT039), and another with a core-peak void fraction profile (MT118). The effect of changing the drag force closures was not significant for the set examined. Poor predictions were found when the lift force and wall lubrication models were incompatible in magnitude. There was no significant effect of changing the liquid phase turbulence model. Changing the bubble-induced turbulence models, however, had a significant impact on the radial void fraction profile. The novel wall force from Lubchenko et al. at the Massachusetts Institute of Technology significantly improved the prediction of the near wall void fraction in the wall peak profile.

关键词： Two-Phase Flow Bubbly Numerical Analysis vertical pipe

Preparation of Semisolid A356 Alloy Feedstock Cast via a pipe Consisting of Partial Inclined and Partial vertical Sections

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Journal of Materials Science & Technology 2009年第2期25卷 273-276页

作者： Xiaorong Yang Weimin Mao School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China School of Materials Science and Engineering Taiyuan University of Science and Technology Taiyuan 030024 China

In the present work, the microstructures of A356 feedstock cast via a pipe consisting of partial inclined and partial vertical sections were investigated. The experimental results indicate that semisolid feedstock with ideal microstructures can be obtained at higher temperatures 645℃ and above by the proposed process, and the solid shell inside the pipe can be avoided at the optimum pouring temperature. Thus the process is attractive for industrial applications. The slanted angle of inclined section has an influence on the optimum pouring temperature. That is, the bigger the slanted angle, the higher the optimum pouring temperature, but accordingly, the greater the possibility of solid shell occurring inside the pipe. Therefore, small slanted angle should be considered first on the premise of ensuring a certain nucleation. The formation of semisolid feedstock is owed to the coactions of wall nucleation and stirring resulting from fluid flow. The inclined section greatly affects nucleation, and the vertical section has an important effect on both nucleation and generating stirring.

关键词： Semisolid Microstructure Inclined pipe vertical pipe Primary α-Al

On the Influence of Vortex-Induced Resistance on Oil-Shale Particle-Slurry Flow in vertical pipes

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Fluid Dynamics & Materials Processing 2021年第2期17卷 413-426页

作者： Li-an Zhao Tieli Wang College of Mining Liaoning Technical UniversityFuxin123000China pipeline Engineering Institute Wuhan Design and Research Institute of China Coal Technology and Engineering GroupWuhan430064China

The transportation in vertical pipelines of particle slurry of oil shale has important applications in several fields(marine mining,hydraulic mining,dredging of river reservoir,etc.).However,there is still a lack of information about the behavior of coarse particles in comparison to that of fine *** this reason,experiments on the fluidization and hydraulic lifting of coarse oil shale particles have been carried *** experimental data for three kinds of particles with an average size of 5 mm,15 mm and 25 mm clearly demonstrate that vortices can be formed behind the *** this basis,a vortex resistance factor K is proposed here to describe this effect.A possible correlation law is defined by means of a data fitting method *** law is validated by an experiment employing particles with an average size of 3.4 *** vortex resistance factor K results in a reduction of the speed of solid particles and an increase in the sliding speed as well as a decrease in the hydraulic *** a result,using this factor,the calculation of the solid particle speed and hydraulic gradient can be made more accurate with respect to measured values.

关键词： Coarse particle hydraulic gradient vertical pipe fluidization

Methods for Reducing Seed Damage in the Technological Process of Cotton Processing

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Engineering（科研） 2022年第3期14卷 119-130页

作者： Muradov Rustam Isakhanov Khamidullo Khosimov Khusanboy Namangan Institute of Engineering and Technology Namangan Uzbekistan

The article describes the transfer of cotton to the next technological process while preserving its natural properties during the initial processing process. The analysis of methods of reducing impact forces when remo... 详细信息

关键词： Cotton Pneumatic Transport Separator Fan pipe Cyclone Stone Holder Auger Solenoid vertical pipe Blade Drum Cleaner Mesh Surface Shaft Vacuum Valve Discharge-Separator Volumetric