An experimental investigation on the speed of sand flow through a fixed porous bed

Wanghua Sui,Ravi Jain,Xinjia Zhang,Yankun Liang,Tao Zhu

doi:10.1038/s41598-017-00082-2

Wanghua Sui, Ravi Jain + Show 3 more

Open Access

https://doi.org/10.1038/s41598-017-00082-2

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Abstract

In this study, we document several experiments that investigate the speed of the flow of fine sand through a fixed porous bed of packed glass beads under various conditions, including the height of the sand column (H) and porous bed (h) and the diameter of the glass beads (D) and sand grains (d). The experiments are conducted with glass beads packed at a constant density and sand at a different dry bulk density. The results show that the height of the sand does not affect the speed of the sand flow. The speed of the sand flow (v) decreases with an increase in h until h approaches a certain value. An equation {boldsymbol{v}}={boldsymbol{a}}sqrt{{bf{g}}{boldsymbol{D}}}{bf{l}}{bf{n}}(frac{{boldsymbol{D}}}{{boldsymbol{kd}}}) is proposed, where a and k are the experimentally determined coefficients. Moreover, the flow of sand through a fixed porous bed could be regarded as parallel flow through multiple pipes, and therefore, the relationship between D and the number and diameter of pipes, N and Dp, are discussed. Further investigations are needed for the result that the flow of sand through a porous bed or multiple parallel pipes cannot be simplified to flow through one orifice with a certain diameter.

Highlights

( ) equation v = a gD ln D is proposed, where a and k are the experimentally determined coefficients. kd the flow of sand through a fixed porous bed could be regarded as parallel flow through multiple pipes, and the relationship between D and the number and diameter of pipes, N and diameter of a pipe (Dp), are discussed
We examined the speed of sand flow through a porous bed under various conditions, including the height of the porous bed (h) and sand column (H), and the diameter of the glass beads (D) and sand (d)
The relationship between the speed of the sand flow (v) and these different conditions was investigated with glass beads packed at a constant density of 0.48 and sand with a dry bulk density of 1.57 g/cm[3]

Summary

Introduction

Further investigations are needed for the result that the flow of sand through a porous bed or multiple parallel pipes cannot be simplified to flow through one orifice with a certain diameter. Granular materials, such as sand, gravel, rice and sugar, have an important role in physics, chemistry, geology and industrial technology. A pile of sand can stand tall and fixed like a solid, but sand can pour through an orifice like liquid This unique phenomenon has received considerable attention, and much work has been devoted to understanding the fundamental differences between fluid and granular flows. The results are helpful for predicting the speed of the grain flow through porous medium in the industry or determining the possibility of geological hazards

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