Particles In Vertical Pipe Research Articles

Numerical simulation on transportation behavior of dense coarse particles in vertical pipe with an optimized Eulerian–Lagrangian method

Solid–liquid two-phase flow with dense coarse particles in the pipeline exists widely in energy and resources engineering, especially in the prospective hydraulic lifting scenario of deep-sea mining. In this paper, the coarse particles' transportation behavior in a vertical pipe is investigated based on an optimized Eulerian–Lagrangian method proposed in our previous work. The coarse particle transportation in the vertical pipe is characterized as multi-processes and multi-physical effects and is not fully captured due to the limitations on experimental apparatus, experimental measurement techniques, and numerical simulation techniques. Little research has been done on the local characteristics of the flow and their effect on the hydraulic lifting performance. The characteristics of the internal flow field, particle retention, and hydraulic lifting efficiency are disturbed under the condition of the continuous supply with the constant inlet two-phase concentration and velocity. The simulation results illustrate that particle transportation process can be roughly divided into three stages, single phase flow stage, mixing stage, and stable transportation stage, and shows a dilute-dense non-continuous flow pattern due to particle retention. Based on parametric studies, the retention phenomenon is alleviated by the increase in the water inlet velocity and almost disappears at approximately 12 000 of the Reynolds number, where the flow pattern transition occurs. Finally, the hydraulic lifting performance, such as a critical lifting condition and the friction loss, is analyzed and the transition of flow pattern is discussed.

Study on velocity distribution of large particle in vertical slurry pipeline

Velocity distribution of vertical pipes with large particle slurry plays an important role in pipeline transportation of minerals in hydraulic coal mining and ocean mining industry. The experiments of particle fluidization and particle vertical lift are conducted and the fluidization data of three kinds of large particles are analyzed. The results show that the vortex resistance prevents particles from moving as the coarse particles move in vertical pipes. An additional coefficient method is proposed to study the vortex resistance by increasing the coefficient of vortex resistance before interference. Mathematical model is established to describe the drag coefficient of the vortex by analyzing the influence factors of the experimental data and the drag coefficient of the vortex. In addition, calculation model of the velocity distribution of large particles in vertical pipe is proposed by analyzing the force, the fluid, and the solid momentum. Moreover, the experimental data of particle transport in vertical pipes are utilized to verify and analyze the proposed model.

Two-dimensional steady state hydrodynamic analysis of gas—solids flow in vertical pneumatic conveying systems

Pneumatic conveying, as a mode of solid particles transportation, is widely used in the petroleum, chemical, petrochemical, gas processing and food processing industries. Within the last decade, there has been increasing demand for an optimized utilization of this technology, particularly in the energy conversion processes. Such optimized utilization of this technology requires good understanding of the hydrodynamic behavior of gas-solids mixture flow in pipes and the capability to predict such behavior. Empirical correlations have been developed in the literature for predicting some of the more commonly sought design variables such as pressure drop. Most of such correlations were developed using one-dimensionally based experimental data. Apart from being limited to the data-base used in developing them, they ignore the effect of radial non-uniformity of the basic variables such as solid velocity, void fraction, etc. More recent experimentations confirm this non-radial uniformity of such important design variables as solid velocity and solid concentration. We present a two-dimensional steady state two-phase hydrodynamic model to describe upward co-current pneumatic conveying of solid particles in vertical pipe. The model incorporates viscous dissipation terms in both the gas phase and the particulate phase. Numerical solution was obtained using the numerical method of lines. The predicted system variables and their distributions under different operating conditions agree with the observed behavior of the system reported in the literature. The predicted solid velocity profiles using this model agree reasonably well with available experimental data.