Horizontal Pneumatic Conveying Research Articles

Comparison of Axial Flow and Swirling Flow on Particle Pickup in Horizontal Pneumatic Conveying

Pneumatic conveying is widely used in coal mining. As the lowest conveying velocity of materials, the pickup velocity is the key to the study of gas–solid two-phase flow. In this study, the pickup velocity of pebble particles was experimentally investigated. When the particle size is 3–9 mm, the airflow velocity was found to suitably describe the results as a function of the pickup velocity and have a high correlation. When the swirl number is 0.2, the optimal swirl number was found for which the highest particle pickup ratio was observed. Based on four different methods, namely, visual observation, mass weighing, coefficient of difference analysis, and determination of the peak-average ratio of the pressure drop in the flow field to measure the pickup velocity of the spraying material, the results showed that the accuracy of the particle pickup velocity obtained through visual observation was the lowest, and when the mass–loss rate of the particle was selected as the measurement index of the pickup velocity, the accuracy was the highest. The results will help to realize the long-distance transportation of spraying materials in inclined roadway under the shaft.

Numerical Simulation on Gas-Solid Two-Phase Flow in Horizontal Pneumatic Conveying Pipe Based on DPM Model

The determination of pipe deposition and optimum conveying velocity in pneumatic conveying has an important impact on conveying efficiency. The Euler-Lagrange method DPM model is used to analyse five different particle sizes and densities of small particles, and the flow pattern in the horizontal pipeline at different particle sizes and densities is derived from the graphs of the maximum discrete phase concentration, particle trajectory and discrete phase concentration distribution for each working condition. The simulation results show that the deposition increases with particle size and density, the optimum conveying speed increases with particle size and density, the larger the deposition, the larger the required conveying velocity. The velocity of 2 m/s can make the particles below 20μm suspended transport, the velocity of 4 m/s allows particles with a particle size of 30μm and a density of 1000 kg/m3 or less to be transported in suspension and 6 m/s allows particles with a density of 2000 kg/m3 or less to be transported in suspension. The aim is to provide a reference for the design of pneumatic conveying systems and the selection of the optimum conveying velocity.

Research on the Pressure Dropin Horizontal Pneumatic Conveying for Large Coal Particles

As a type of airtight conveying mode, pneumatic conveying has the advantages of environmental friendliness and conveying without dust overflow. The application of the pneumatic conveying system in the field of coal particle conveying can avoid direct contact between coal particles and the atmosphere, which helps to reduce the concentration of air dust and improve environmental quality in coal production and coal consumption enterprises. In order to predict pressure drop in the pipe during the horizontal pneumatic conveying of large coal particles, the Lagrangian coupling method and DPM (discrete particle model) simulation model was used in this paper. Based on the comparison of the experimental results, the feasibility of the simulation was verified and the pressure drop in the pipe was simulated. The simulation results show that when the flow velocity is small, the simulation results of the DPM model are quite different from that of the experiment. When the flow velocity is large, the large particle horizontal pneumatic conveying behavior predicted by the model is feasible, which can provide a simulation reference for the design of the coal pneumatic conveying system.

Prediction of Horizontal Pneumatic Conveying of Large Coal Particles Using Discrete Phase Model

The pneumatic conveying focusing on gas‐solid two‐phase flow plays an important role in a conveying system. Previous work has been conducted in the fields of small particles, where the size was less than 5 mm; however, there are few studies regarding large sizes (>5 mm). In order to predict the horizontal pneumatic conveying of large coal particles, the coupling methods based on the Euler–Lagrange approach and discrete phase model (DPM) have been used for the simulated research. Compared with the experimental results under the same working condition, the particle trajectory obtained by simulation is similar to the particle distribution at the same position in the experiment, and it turns out that the simulation method is feasible for the horizontal pneumatic conveying of large particles. Multifactor simulations are also carried out to analyse the effects of particle size, flow field velocity, solid‐gas rate, and pipe diameter on the wall abrasion during horizontal pneumatic conveying, which provides simulation reference and design guide for pneumatic conveying of large particles.

Effect of Dune Formation on Pressure Drop in Horizontal Pneumatic Conveying System

Pneumatic conveying is widely used in industries handling large amount of granular materials to transport the solid particles; however, the process is energy intensive as an instability of flow sets in the transportation line even in the dilute regime, causing large fluctuations in the line pressure drop, the reason of which is not clearly understood. Here, we investigate, both by experiments and by using numerical simulations, the instability transition regimes and identify the reasons of the fluctuations observed in the line pressure drop in a horizontal pneumatic transport system operating at near-saltation conditions. It is observed that the increase in the pressure drop (immediately after the saltation) is accompanied by the formation of distinct dunes. It is also observed that the line pressure drop depends on the axial location of the dune and shows large fluctuations in the regime where the dunes are unstable. Results obtained from the numerical simulations suggest that the increase in the line pressure drop in the presence of dunes is essentially due to the shear stresses at the dune surface which are larger than that for the flows in clean pipe.

The Influence of Physical Properties on Total Friction Factor in Horizontal Dilute Pneumatic Conveying of Plastic Particles

The Influence of Physical Properties on Total Friction Factor in Horizontal Dilute Pneumatic Conveying of Plastic Particles

Flow characteristics in horizontal pneumatic conveyance at low fluid velocities—3: additional pressure drop and the friction factor

In this paper, a fundamental equation for the friction factor of an additional pressure drop due to solid particles is first derived based on the observed flow pattern of solid particles reported in part 1 on a fully developed flow at low fluid velocities in horizontal pipes. Next, an empirical equation for the friction factor is obtained by the substitution of the parameter of the gravitational force and the velocity ratio of particles to fluid determined in part 2 into the foregoing equation. More than 95% of the values calculated by the equation fall within ± 20% of the present experimental values.

モーノポンプによる粉体の高濃度水平輸送に関する研究

The horizontal pneumatic conveyance of powder was experimentally investigated by using a Mohno pump. The frequency distribution of the plugs, the characteristics of plug velocity, plug length, pressure gradient and solid friction factor were clarified according to the variation in pipe diameter, the speed of pump rotation and air velocity.

Flow characteristics in horizontal pneumatic conveyance at low fluid velocities–2: solid particle velocity and the velocity ratio of particles to fluid

In this paper a basic equation for the velocity ratio of particles to fluid was derived on the basis of the observation of solid flow patterns given in a previous report on an established flow at low fluid velocities in horizontal pipes. Measurements of the solid particle velocity for the flow were also conducted by measuring the impulsive force of the solids-fluid two phase flow by the use of a ballistic pendulum. The unknown quantities in the equation were determined by analyzing the experimental data and an empirical equation was obtained. More than 95% of the values calculated by the equation fall within ± 12% of the experimental values.

低流速域での水平管内空気輸送における粒子速度の測定法

低流速域での水平管内空気輸送における粒子速度の測定法

Flow characteristics in horizontal pneumatic conveyance at low fluid velocities—1: solid flow patterns

Instantaneous photographs of solid flow patterns were taken with a camera simultaneously operated with a stroboscope to investigate the flow characteristics of steady state pneumatic transportation of solids in horizontal pipes at low fluid velocities. The experimental results were as follows: the solids flow along the bottom of the pipes forming dunes at periodic intervals. The height and the length of each dune under such conditions are related to the mass flow rate ratio of solids-to-fluid, as well as to the fluid velocity for each pipe diameter. When the mass flow rate ratio of solids-to-fluid is greater than 10, these values become constant, independent of the ratio. However, the angle of slope and the pitch length of the dune are both independent of the mass flow rate ratio of solids-to-fluid.

Pressure Drop in a Horizontal Pneumatic Conveyance Transporting Solid Particles Consisting of Different Sizes

This paper deals with the pressure drop in horizontal pipelines, through which solid particles consisting of two different sizes are conveyed.Two kinds of glass beads, the mean diameter of which are 0.45mm and 1.85mm respectively and the mean density of each is 2500kg/m3, were used.The following results are obtained: When grounded brass pipelines are used, the differences between the pressure drops caused by large and small conveyed particles are in inverse proportion to the mean air velocity and particle mass flow-rate. When large and small particles are simultaneously conveyed, the pressure drop increases at a particle supply ratio of 50-75%.When acrylic pipelines are used, the material and boundary condition of the pipes and the particles extremely affect the pressure drop. The effects of particle size are not evident in the acrylic pipelines. When large and small particles are simultaneously conveyed, the pressure drop decreases by mixing small particles with large particles. With a large mass flow rate (5kg/min), the pressure drops rise in the vicinity of a supply ratio of 50%.

A Comparison of Correlations for Saltation Velocity in Horizontal Pneumatic Conveying

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Comparison of Correlations for Saltation Velocity in Horizontal Pneumatic ConveyingPeter J. Jones and L. S. LeungCite this: Ind. Eng. Chem. Process Des. Dev. 1978, 17, 4, 571–575Publication Date (Print):October 1, 1978Publication History Published online1 May 2002Published inissue 1 October 1978https://doi.org/10.1021/i260068a031RIGHTS & PERMISSIONSArticle Views414Altmetric-Citations9LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (528 KB) Get e-Alerts

On the Collision of Particles against the Pipe Wall in Horizontal Pneumatic Conveyance

Using quartz sands and glass beads as solid particles, the relation among η (collision ratio of particles against pipe wall), G (particles flow rate), and λs (additional pressure loss coefficient by particles) was examined.Results obtained are as follows;(1) With increasing G, η increased at first to maximum value, and then decreased.(2) Following linear relationship between η and λs was obtained in some range of λs. λs=a-bη

Velocity and Pipe Friction of Soya-Beans in the Horizontal Pneumatic Conveying Pipe

Velocity and Pipe Friction of Soya-Beans in the Horizontal Pneumatic Conveying Pipe

On the Pressure Drop and Clogging Limit in the Horizontal Pneumatic Conveyance Pipe

By using the theoretical formula and the empirical one which one of the authors has published, the pressure drop and the clogging limit in a horizontal pneumatic conveyance pipe were calculated for several conditions and the results were compared with many experimental results. For six other kinds of formulas on pressure drop and clogging limit which have been published by the other authors, similar calculations were accomplished. Consequently, it has been concluded that S. Sugwara and S. Kikkawa's formula is the most excellent from every point of view followed by E. Muschelknautz's formula.

On the Pressure Drop and the Clogging Limit in a Horizontal Pneumatic Conveyance Pipe

On the Pressure Drop and the Clogging Limit in a Horizontal Pneumatic Conveyance Pipe