The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Yuji Tomita - One of the best experts on this subject based on the ideXlab platform.
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particle velocity and concentration characteristics in a horizontal dilute swirling flow Pneumatic Conveying
Powder Technology, 2000Co-Authors: Hui Li, Yuji TomitaAbstract:An experimental study concerning particle behaviors in a horizontal dilute swirling flow Pneumatic Conveying was performed. Measurements of particle velocities and concentration profiles have been carried out using the photographic image technique. From the experimental results, it is found that mean particle velocity of swirling flow Pneumatic Conveying is lower than that of conventional Pneumatic Conveying in the range of high gas velocity, but the higher mean particle velocity in swirling flow Pneumatic Conveying can be obtained at low gas velocity. The particle concentration profiles in the swirling flow Pneumatic Conveying exhibit symmetric distributions with respect to the pipe axis and the higher particle concentration appears near the wall in the acceleration region. In developed region, the particle concentration profiles of the swirling flow Pneumatic Conveying show anti-symmetric distributions, and the higher particle concentration appear at the bottom of pipe. However, the particle concentrations of the swirling flow Pneumatic Conveying at the bottom of pipe are lower than that of axial flow Pneumatic Conveying.
Hui Li - One of the best experts on this subject based on the ideXlab platform.
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CHARACTERISTICS OF A HORIZONTAL SWIRLING FLOW Pneumatic Conveying WITH A CURVED PIPE
Particulate Science and Technology, 2000Co-Authors: Hui LiAbstract:ABSTRACT In order to prevent flow blockage phenomenon and to reduce the impact of particles on the wall of the bend, an experimental study of the swirling flow Pneumatic Conveying system with a horizontal curved pipe was carried out in this work. The experiment was performed in a 90-deg pipe bend with pipe diameter 75 mm and centerline curvature ratio 12. The straight pipes with 75 mm inside diameter at the upstream and downstream of the bend were 1.3 m and 4.0 m in lengths, respectively. The initial swirl number was varied from 0.22 to 0.60, the mean air velocity from 10 to 20 m/s, and the solid mass flow rate from 0.07 to 0.68 kg/s. It is found that in the lower air velocity range, the overall pressure drop of the swirling flow Pneumatic Conveying shows a lower tendency than that of axial flow Pneumatic Conveying. The minimum air velocities can be decreased by using the swirling flow Pneumatic Conveying. From the visualization of particle flow patterns, the impact of particles on the wall of the bend ca...
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particle velocity and concentration characteristics in a horizontal dilute swirling flow Pneumatic Conveying
Powder Technology, 2000Co-Authors: Hui Li, Yuji TomitaAbstract:An experimental study concerning particle behaviors in a horizontal dilute swirling flow Pneumatic Conveying was performed. Measurements of particle velocities and concentration profiles have been carried out using the photographic image technique. From the experimental results, it is found that mean particle velocity of swirling flow Pneumatic Conveying is lower than that of conventional Pneumatic Conveying in the range of high gas velocity, but the higher mean particle velocity in swirling flow Pneumatic Conveying can be obtained at low gas velocity. The particle concentration profiles in the swirling flow Pneumatic Conveying exhibit symmetric distributions with respect to the pipe axis and the higher particle concentration appears near the wall in the acceleration region. In developed region, the particle concentration profiles of the swirling flow Pneumatic Conveying show anti-symmetric distributions, and the higher particle concentration appear at the bottom of pipe. However, the particle concentrations of the swirling flow Pneumatic Conveying at the bottom of pipe are lower than that of axial flow Pneumatic Conveying.
Peter W Wypych - One of the best experts on this subject based on the ideXlab platform.
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energy loss at bends in the Pneumatic Conveying of fly ash
Particuology, 2015Co-Authors: Naveen Tripathi, Soumya Suddha Mallick, Atul Sharma, Peter W WypychAbstract:Abstract An accurate estimation of the total pressure drop of a pipeline is important to the reliable design of a Pneumatic Conveying system. The present paper presents results from an investigation into the modelling of the pressure drop at a bend in the Pneumatic Conveying of fly ash. Seven existing bend models were used (in conjunction with solids friction models for horizontal and vertical straight pipes, and initial acceleration losses) to predict the total pipeline pressure drop in Conveying fly ash (median particle diameter: 30 μm; particle density: 2300 kg/m 3 ; loose-poured bulk density: 700 kg/m 3 ) in three test rigs (pipelines with dimensions of 69 mm inner diameter (I.D.) × 168 m length; 105 mm I.D. × 168 m length; 69 mm I.D. × 554 m length). A comparison of the Pneumatic Conveying characteristics (PCC) predicted using the seven bend models and experimental results shows that the predicted total pipeline PCC and trends depend on the choice of bend model. While some models predict trends that agree with the experimental results, other models predicted greater bend pressure drops for the dense phase of fly ash than for the dilute phase. Models of Pan, R. (1992). Improving scale-up procedures for the design of Pneumatic Conveying systems. Doctoral dissertation, University of Wollongong, Australia, Pan, R., & Wypych, P.W. (1998). Dilute and dense phase Pneumatic Conveying of fly ash. In Proceedings of the sixth International Conference on Bulk Materials Storage and Transportation (pp. 183–189), Wollongong, NSW, Australia and Chambers, A.J., & Marcus, R.D. (1986). Pneumatic Conveying calculations. In Proceedings of the second International Conference on Bulk Materials Storage and Transportation (pp. 49–52), Wollongong, Australia reliably predicted the bend losses for systems Conveying fly ash over a large range of air flows.
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Stress field measurements in slug flow Pneumatic Conveying
2012Co-Authors: Peter W Wypych, Mark Jones, David B Hastie, T. Krull, Alan W. RobertsAbstract:Dense-phase is a specific form of Pneumatic Conveying, in which bulk solids are transported along a pipeline at relatively low Conveying speeds. Slug-flow Pneumatic Conveying is a full-bore mode of flow within the dense-phase flow regime where granular materials are transported as plugs at Conveying speeds generally below 5 m/s. Especially applications in the food and processing industry require Conveying of fragile and brittle materials which makes this form of Pneumatic Conveying well suited due to its more gentle handling characteristics. An accurate assessment of the stress field and the wall friction is the crucial step to a reliable prediction of the Conveying parameters, mainly the pressure drop for any given combination of air and material mass flow rate. With the help of a newly developed test apparatus, two important parameters can now be determined for a moving material slug; the wall friction coefficient and the stress transmission coefficient, which relates the slug’s lateral to axial stress. This paper reports on the experiments conducted with the stress transmission test cell while it was inserted into a full scale Pneumatic Conveying line.
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Troubleshooting Pneumatic Conveying systems : Bulk materials handling
1999Co-Authors: Peter W WypychAbstract:Despite the increasing popularity of Pneumatic Conveying in industry, many problems are still occurring during plant design, commissioning and operation. Quite often the root cause of the problem is a lack of appreciation and understanding of the relevant fundamentals. This paper describes some of the key issues often neglected in the design and analysis of Pneumatic Conveying systems, and demonstrates certain limitations of current design practice. Various case studies also are presented to demonstrate how seemingly impossible problems can be solved by understanding and modelling the relevant fundamental mechanisms and using some good imagination and common-sense.
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Low-velocity Pneumatic Conveying of Fine Powders
1995Co-Authors: B. Mi, Peter W WypychAbstract:Most studies into low-velocity Pneumatic Conveying are confined to the transportation of coarse granular materials that display natural slugging ability. However, some fine powders, such as semolina, also exhibit natural slugging tendency and can be good candidates for low-velocity Pneumatic Conveying. This paper studies the Conveying characteristics of fine powders by Conveying semolina over a broad range of operating conditions. From this study it is found that the low-velocity Pneumatic Conveying performance of fine powder is quite different to coarse granular materials. The most significant effect appears to be slug velocity. Based on experimental results, a model for predicting pipeline pressure drop in low-velocity Pneumatic Conveying of fine powders is obtained by modifying a model that was developed previously for coarse granular materials. The results predicted by the modified model agree well with the experimental data.
Aibing Yu - One of the best experts on this subject based on the ideXlab platform.
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computational study of flow regimes in vertical Pneumatic Conveying
Industrial & Engineering Chemistry Research, 2009Co-Authors: Shibo Kuang, Aibing YuAbstract:Pneumatic Conveying is an important technology in industries to transport bulk materials from one location to another. Different flow regimes have been observed in such a transportation process depending on operational conditions, but the underlying fundamentals are not clear. This paper presents a three-dimensional numerical study of vertical Pneumatic Conveying by a combined approach of discrete element model for particles and computational fluid dynamics for gas. The approach is verified by comparing the calculated and measured results in terms of particle flow pattern and gas pressure drop. It is shown that flow regimes usually encountered in vertical Pneumatic Conveying and their corresponding phase diagram can be reproduced. Then forces governing the behavior of particles, such as the particle−particle, particle−fluid, and particle−wall forces, are analyzed in detail. It is shown that the roles of these forces vary with flow regimes. A new phase diagram is proposed in terms of the key forces, which ...
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discrete element simulation for Pneumatic Conveying of granular material
Aiche Journal, 2006Co-Authors: Chihwa Wang, Aibing YuAbstract:The Pneumatic transport of granular material is a common operation frequently employed to transport solid particles from one location to another. It is well established in the literature that different flow regimes can arise in such transportation processes depending on the system geometry and operating conditions used. In this study, the Pneumatic transports of solid particles in both vertical and horizontal Conveying lines were studied numerically using the discrete element method coupled with computational fluid dynamics. The simulation outputs corresponded well with reported experimental observations in terms of the different flow regimes obtained at different operating conditions. In the vertical Pneumatic Conveying simulations, two different flow patterns corresponding to the experimentally observed dispersed flow and plug flow regimes were obtained at different gas velocities and solid concentrations. Similarly, the homogeneous flow, stratified flow, moving dunes, and slug flow regimes previously reported to occur in horizontal Pneumatic Conveying were also reproduced computationally in this study. Solid concentration profiles obtained by spatial averaging along the length of the pipe showed a symmetrical but non-uniform distribution for dispersed flow and an almost flat distribution for plug flow in vertical Pneumatic Conveying. The profile for stratified flow in horizontal Pneumatic Conveying showed higher solid concentration near the bottom wall due to the effects of gravitational settling, while that for slug flow was flat. Hysteresis in solid flow rates was observed in vertical Pneumatic Conveying near the point where transition between the dispersed and plug flow regimes was expected to occur. Solid flow rates were also found to be more sensitive towards the coefficient of friction than the coefficient of restitution of particles and the pipe walls in a sensitivity analysis study of these parameters. © 2005 American Institute of Chemical Engineers AIChE J, 2006
George E. Klinzing - One of the best experts on this subject based on the ideXlab platform.
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Review of unusual and some unexplained phenomena in Pneumatic Conveying
Particulate Science and Technology, 2016Co-Authors: George E. KlinzingAbstract:ABSTRACTThis paper will review several phenomena and applications of Pneumatic Conveying which are unusual in nature and not found in the standard applications of Pneumatic Conveying in solid processing. The effect of reduced gravity of Pneumatic Conveying in the space shuttle will be cited along with other earth-based reduced-gravity experiments. In our laboratory, we studied the relationship between dilute and dense-phase Conveying proposing a thermodynamic analogy in interpreting Pneumatic Conveying operations. We also explored the potential to relate the different parameters in Pneumatic Conveying to a generalized phase diagram. Our laboratory also studied many facets of electrostatics and their effect from elimination of the effect to utilization in the development of flowmeters. It was found that the use of a Roots blower in Conveying dilute-phase cement yields some fascinating results that show drag reduction. Also showing unexpected results were the conveyance of particles that undergo a physical ...
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Single Phase Flow in Pneumatic Conveying Systems
Particle Technology Series, 2010Co-Authors: George E. Klinzing, Fatimah Rizk, R. Marcus, L.s. LeungAbstract:The design of any Pneumatic Conveying system requires a basic understanding of air flow in pipes and ducts as well as an appreciation of the various prime movers used to supply air.
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An overview of Pneumatic Conveying systems and performance
Particle Technology Series, 2010Co-Authors: George E. Klinzing, R. Marcus, F Rizk, L.s. LeungAbstract:This chapter sets the scene for understanding and design of Pneumatic Conveying systems. Pneumatic Conveying is broken down into its component parts indicating the further details will be given in the following chapters. The basic state diagram is presented and the various flow conditions are related to this diagram. Some of the recent comprehensive discussions on Pneumatic Conveying are cited.
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Pressure fluctuations in Pneumatic Conveying systems
Powder Technology, 1993Co-Authors: S.v. Dhodapkar, George E. KlinzingAbstract:Abstract The pressure fluctuations generated in Pneumatic Conveying of solids in a horizontal piping arrangement have been studied in order to provide a technique for flow pattern identification and control of the Pneumatic Conveying operation. Practitioners of Pneumatic Conveying have used flow noise production in Pneumatic Conveying as a technique to diagnose the operation of such systems. The pressure fluctuations measured were placed in power spectral density function (PSDF) format and related to the flow patterns, visually observed. Distinguishing PSDFs were observed for the various flow pattern regimes. The effect of particle size, system configuration, pressure transducer type and acquisition parameters were explored. The analysis was carried out on-line so that control strategies can be employed. The pressure tap spacing did not influence the spectra generated at the various flow regimes. Static pressure transducers proved more reliable for homogeneous and stratified flows detection while differential pressure transducers were preferred for the dune/slug flow condition.
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Pneumatic Conveying of solids a theoretical and practical approach
Drying Technology, 1993Co-Authors: R. Marcus, L.s. Leung, George E. Klinzing, F RizkAbstract:An overview of Pneumatic Conveying systems and performance single phase flow in Pneumatic Conveying systems fluid and particle dynamics fundamentals flow regimes in vertical and horizontal Conveying principles of Pneumatic Conveying feeding of Pneumatic Conveying systems flow in standpipes and gravity conveyors an overview of high pressure systems including long distance and dense phase Pneumatic Conveying systems gas-solids separation the flow behaviour of solids from silos wear in Pneumatic Conveying systems ancillary equipment control of Pneumatic transport instrumentation system design and worked examples.
