The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Mark Jones - One of the best experts on this subject based on the ideXlab platform.
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Transport boundaries and prediction of the slug velocity and layer fraction in horizontal slug Flow pneumatic conveying
Chemical Engineering Science, 2020Co-Authors: O. Orozovic, Mark Jones, Kenneth Williams, A. Lavrinec, H. Rajabnia, George E. KlinzingAbstract:Abstract The poorly understood mechanisms of slug Flow remain an obstacle for widespread application of this Dense Phase Flow. The parameters that characterise the Flow have repeatedly been observed to have a bounded range of operating conditions; however, the ability to reliably predict these boundaries has not achieved the same level of repeatability. This paper presents a model to predict the absolute maximum transport boundaries for slug velocity and the absolute minimum transport boundaries for the layer fraction as a function of the gas mass Flow rate. The predicted transport boundaries are supported by measurements, following which, the model is further developed as a prediction tool, where very good agreement with measurements is achieved. As the model provides relationships between all of the key parameters of slug Flow, analysis is provided demonstrating the ability of the model to be applied as a convenient design tool for slug Flow pneumatic conveying systems.
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Transient characteristics of fine powder Flows within fluidized Dense Phase pneumatic conveying systems
Powder Technology, 2019Co-Authors: Yassin Alkassar, Mark Jones, Vijay K. Agarwal, Niranjana Behera, Raj K. PandeyAbstract:Abstract The objective of this paper is to report the experimental findings related to the pressure fluctuations in the fluidized Dense Phase pneumatic conveying of fine powders in the pipeline. Investigation has also been carried out to understand the relation between pressure pulse characteristics and specific power consumption and pneumatic conveying parameters. In addition, the transition in mode of Flow along the downstream of Flow of fine powders has been assessed and discussed. The wavelet analysis (Daubechies db4 wavelet) of signals of air pulses revealed that the moving bed Flow possesses the transient feature and pulsatile phenomenon characterized by multiple amplitudes and random frequencies. Variations of pulse structures along the length of pipeline have been observed due to occurring of frequent aeration and de-aeration of dunes during the conveying. Substantial variations in pulse structures have also been found with different types of bulk materials. Pulse velocities of air between two data points are found higher at high solid loading ratios leading to low voidage in case of Dense Phase Flow.
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High Speed Visualization of Pneumatic Conveying of Materials in Bypass System
Advanced Materials Research, 2012Co-Authors: Mark Jones, Kenneth Williams, Bin Chen, A. A. Cenna, Ying WangAbstract:Dense Phase pneumatic conveying is preferable over dilute Phase conveying in many industries as lower transport velocities are beneficial due to reduced attrition of the particles and reduced wear. However, Dense Phase conveying is critically dependent on the physical properties of the materials to be conveyed. For many materials which are either erosive or fragile, they do not exhibit the physical properties required to be conveyed reliably in a low velocity, Dense Phase Flow regime. This can be serious problem in the food, chemical and pharmaceutical industries. One satisfactory approach which has been widely applied is the use of bypass systems. Bypass pneumatic conveying systems provide the capacity of transporting some materials that are not naturally suitable for Dense Phase Flow. Bypass pneumatic conveying systems also provide a passive capability to reduce minimum particulate transport velocities. In this study, pneumatic conveying experiments were carried out in a 79 mm diameter main pipe with a 27 mm inner diameter bypass pipe with orifice plate flute arrangement. Alumina, fly ash and sand were conveyed in the tests. High speed camera visualization was employed to study the Flow regimes of bypass pneumatic transport systems and investigate the mechanism of material blockage inhibition provided by these systems. For alumina and fly ash, it was found that particulate material blockages were inhibited in bypass systems due to the air penetration into the particulate volume as a result of orifice plate airFlow resistance. For the bypass pneumatic conveying of sand, the splitting of a long plug into two smaller plugs was observed. One of the primary concerns of bypass system is the wear of the bypass line. Material such as alumina is inherently abrasive by nature. For internal bypass systems, there is limited ability to monitor the state of the inner bypass tube while in operation. The particle velocity in the pipeline has been measured from the high speed video of the Flow. The experimental result also showed that the conveying velocity of bypass system is much lower when compared conventional single bore pipelines. Based on the models developed for the assessment of service life of pneumatic conveying pipelines, the thickness loss of the bypass pipe has been estimated. It has been estimated that for a 3mm bypass tube wall thickness, a wear hole is created in approximately 2.5 years for a particle velocity of 3 m/s and 4 months for a particle velocity of 10 m/s.
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Stress field measurements in slug Flow pneumatic conveying
2012Co-Authors: Peter W Wypych, David B Hastie, T. Krull, Mark Jones, 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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A probability approach for investigation and determination of material slugs/air gap
2009Co-Authors: A. Dresel, Kenneth Williams, U. Teipel, Mark JonesAbstract:In the past, pressure drop prediction models in low velocity Dense-Phase pneumatic conveying largely assumed steady-state conditions during conveying. However, the Dense-Phase Flow regime is rather characterised by transient dunes or discrete full bore slug Flows, which limit steady-state approaches in their ability to accurately describe these systems. Steady-state approaches as well as pressure drop prediction models for discontinuous slug Flow depend on the total slug length - sum of all slugs in a pipeline - which can be related to the air-gap/slug-length ratio. As such, there is a need to accurately predict this ratio. This paper reports on investigations on describing slug length, air gap length and air-gap/slug-length ratio using a probabilistic approach. In particular, the primary variables of slug lengths and air gap lengths have been modelled under the assumption that their variations have logarithmic normal distributions. Subsequently, the probability distribution of air-gap/slug-length ratios has also been derived from the logarithmic distributions of these two basic variables. The resulting distribution models have been applied to compare experimental slug- and air gap length data observed from multi-slug conveying trails for polyethylene pellets, which showed a strong influence of the solid loading ratio. The derived probability model for the air-gap/slug-length ratio was also validated by the Kolmogorov-Smimov (K-S) test for goodness of fit.
Soumendu Jana - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation of fluidized Dense-Phase pneumatic conveying of powders to develop improved model for solids friction factor
Particuology, 2017Co-Authors: Baldeep Kaur, Soumya Suddha Mallick, Anu Mittal, Renhu Pan, Soumendu JanaAbstract:Accurate prediction of the solids friction factor through horizontal straight pipes is important for the reliable design of a pneumatic conveying system, but it is a challenging assignment to date because of the highly concentrated, turbulent, and complex nature of the gas–solids mixture. Power-station fly ash was transported through different pipeline configurations. Numerical simulation of the Dense-Phase pneumatic conveying systems for three different solids and two different air Flow rates have shown that particle and actual gas velocities and the ratio of the two velocities increases in the Flow direction, whereas the reverse trend was found to occur for the solids volumetric concentration. To develop a solids friction-factor model suitable for Dense-Phase Flow, we modified an existing pure dilute-Phase model by incorporating sub-models for particle and actual gas velocities and impact and solids friction factor. The solids friction-factor model was validated by using it for scale-up predictions for total pipeline pressure drops in longer and larger pipes and by comparing experimental and predicted pneumatic conveying characteristics for different solids Flow rates. The accuracy of the prediction was compared with a recently developed two-layer-based model. We discussed the effect of incorporating the particle and actual gas velocity terms in the solids friction-factor model instead of superficial air velocity.
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on developing improved modelling and scale up procedures for pneumatic conveying of fine powders
Powder Technology, 2017Co-Authors: Baldeep Kaur, Peter W Wypych, Soumya Suddha Mallick, Anu Mittal, Soumendu JanaAbstract:Abstract Pneumatic transport of fine powders in fluidized Dense-Phase mode is becoming increasingly popular in various industries, such as power, chemical, cement, refinery, alumina, pharmaceutical, limestone, to list a few, because of the reasons of reduced gas Flow rate and power consumption, decreased conveying velocities, improved product quality control, reduced pipeline sizing and wear rate, increased workplace safety etc. For the reliable design of a pneumatic conveying system, it is important to accurately predict the total pipeline pressure drop. However, accurate prediction of pressure drop from an improved understanding of the fundamental transport mechanism of fluidized Dense-Phase Flow condition has only made limited progress till now because of the highly concentrated and turbulent nature of the gas-solids mixture. Power plant fly ash (median particle diameter: 30 μm; particle density: 2300 kg/m3; loose-poured bulk density: 700 kg/m3) was conveyed through different pipelines (69 mm I.D. × 168 m long; 105 mm I.D. × 168 m long; 69 mm I.D. × 554 m long). 8 different fly ash samples were tested in a fluidizing column for their deaeration characteristics and fluidized bulk densities were determined. Governing equations of Flow for the Dense-Phase pneumatic conveying system of fine powders were solved using Runge-Kutta-Fehlberg (RKF45) method for different fluidized bulk densities of fly ash and air Flow rates. The results have shown that the particle and actual gas velocities and the ratio of the two velocities increase in the direction of Flow, while a reverse trend was apparent for the solids volumetric concentration. The results were compared against the predictions obtained using existing empirical relations for particle velocity. To develop an improved model for solids friction factor, an existing reliable pure dilute-Phase model has been modified for Dense-Phase Flow condition by incorporating sub-models for particle to actual gas velocity and impact and solids friction factor. The developed solids friction factor model was validated by using it to predict the total pipeline pressure drops for larger and longer pipelines and by comparing the experimental and predicted pneumatic conveying characteristics. The results have shown improved reliable predictions and that the model is capable of addressing the gradual transition of Flow mechanism from Dense- to dilute-Phase. The accuracy of prediction is similar (in fact better in certain scale-up cases) when compared to a recently developed two-layer based model (developed by some of the authors). The results demonstrate the importance of incorporating particle and actual gas velocity terms in the model of solids friction factor instead of the prevailing techniques that overly depend on using superficial gas velocities.
Shimin Wang - One of the best experts on this subject based on the ideXlab platform.
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ANALYSES OF CHARACTERISTICS OF RING-SHAPED ELECTROSTATIC METER
Chemical Engineering Communications, 2009Co-Authors: Jianyong Zhang, J. M. Coulthard, Shimin WangAbstract:This article describes the characteristics of ring-shaped electrostatic pulverized fuel meters and their applications. At the University of Teesside, UK, the electrostatic technique has been used to measure pulverized fuel Flow concentration, velocity, and mass Flow rate under lean-Phase condition. The mathematic model has been developed to express the relationship between the root-mean-square (rms) value of the meter's output voltage and solids mass Flow rate. The effects of solids velocity and particle size on measurements have also been reflected in the model. Furthermore, the model presents the sensitivity variations over the cross-sectional area of meter and along the pipe axis. The article also introduces the research carried out at Southeast University in China, where the technique has been extended to measure Dense-Phase Flow of pulverized coal, which is common in gasification and blast furnaces.
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Analyses of Characteristics of Ring‐shaped Electrostatic Meter
AIP Conference Proceedings, 2007Co-Authors: Jianyong Zhang, J. M. Coulthard, Shimin WangAbstract:This paper describes the characteristics of ring‐shaped electrostatic pulverised fuel meters and their applications. At the University of Teesside, UK, electrostatic technique has been used to measure pulverised fuel Flow concentration, velocity and mass Flow rate under lean Phase condition. The mathematic model has been developed to express the relationship between the root mean square (rms) value of meter’s voltage output and solids concentration and mass Flow rate. The effects of solids velocity and particle size on measurements have also been reflected in the model. The model also presents the sensitivity variations over cross the sectional area of meter and along the pipe axis. The paper also introduces the research carried out in the Southeast University in China, where the technique has been extended to measure Dense Phase Flow of pulverised coal, which is common in gasification and blast furnaces.
Peter W Wypych - One of the best experts on this subject based on the ideXlab platform.
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on developing improved modelling and scale up procedures for pneumatic conveying of fine powders
Powder Technology, 2017Co-Authors: Baldeep Kaur, Peter W Wypych, Soumya Suddha Mallick, Anu Mittal, Soumendu JanaAbstract:Abstract Pneumatic transport of fine powders in fluidized Dense-Phase mode is becoming increasingly popular in various industries, such as power, chemical, cement, refinery, alumina, pharmaceutical, limestone, to list a few, because of the reasons of reduced gas Flow rate and power consumption, decreased conveying velocities, improved product quality control, reduced pipeline sizing and wear rate, increased workplace safety etc. For the reliable design of a pneumatic conveying system, it is important to accurately predict the total pipeline pressure drop. However, accurate prediction of pressure drop from an improved understanding of the fundamental transport mechanism of fluidized Dense-Phase Flow condition has only made limited progress till now because of the highly concentrated and turbulent nature of the gas-solids mixture. Power plant fly ash (median particle diameter: 30 μm; particle density: 2300 kg/m3; loose-poured bulk density: 700 kg/m3) was conveyed through different pipelines (69 mm I.D. × 168 m long; 105 mm I.D. × 168 m long; 69 mm I.D. × 554 m long). 8 different fly ash samples were tested in a fluidizing column for their deaeration characteristics and fluidized bulk densities were determined. Governing equations of Flow for the Dense-Phase pneumatic conveying system of fine powders were solved using Runge-Kutta-Fehlberg (RKF45) method for different fluidized bulk densities of fly ash and air Flow rates. The results have shown that the particle and actual gas velocities and the ratio of the two velocities increase in the direction of Flow, while a reverse trend was apparent for the solids volumetric concentration. The results were compared against the predictions obtained using existing empirical relations for particle velocity. To develop an improved model for solids friction factor, an existing reliable pure dilute-Phase model has been modified for Dense-Phase Flow condition by incorporating sub-models for particle to actual gas velocity and impact and solids friction factor. The developed solids friction factor model was validated by using it to predict the total pipeline pressure drops for larger and longer pipelines and by comparing the experimental and predicted pneumatic conveying characteristics. The results have shown improved reliable predictions and that the model is capable of addressing the gradual transition of Flow mechanism from Dense- to dilute-Phase. The accuracy of prediction is similar (in fact better in certain scale-up cases) when compared to a recently developed two-layer based model (developed by some of the authors). The results demonstrate the importance of incorporating particle and actual gas velocity terms in the model of solids friction factor instead of the prevailing techniques that overly depend on using superficial gas velocities.
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Stress field measurements in slug Flow pneumatic conveying
2012Co-Authors: Peter W Wypych, David B Hastie, T. Krull, Mark Jones, 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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evaluation of scaleup procedures using system approach for pneumatic conveying of powders
Particulate Science and Technology, 2010Co-Authors: Soumya Suddha Mallick, Peter W WypychAbstract:This article presents results from an ongoing research effort aimed towards developing a validated scaleup procedure for pressure drop for the Dense-Phase pneumatic conveying of powders. Two existing/popular forms of the “system” approach for scaling up of diameter were evaluated. The validity of the current technique for length scaleup using a “system” approach was also examined. The existing method showed good potential for dilute-Phase Flow, but resulted in appreciable under-predictions when predicting for Dense-Phase Flow. The effect of bends on the accuracy of the method was also investigated. In this study, steady-state conveying data of four different powders conveyed in various pipes (diameter/lengths) were used for the purpose of scaleup investigations.
Soumya Suddha Mallick - One of the best experts on this subject based on the ideXlab platform.
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A study of energy loss due to particle to particle and wall collisions during fluidized Dense-Phase pneumatic transport
Powder Technology, 2020Co-Authors: Kapil Sharma, Soumya Suddha Mallick, Anu MittalAbstract:Abstract This paper results from ongoing research into the modelling of solids friction for fluidized Dense-Phase pneumatic transport of fine powders. Energy loss due to particle to particle and particle to wall collisions have been modelled. A new model for particle velocity has been introduced using numerical analysis and variable fluidized bulk density, which has shown that slip velocity decreases with an increase in the mass Flow rate of air and dimensionless length. A new modified two-layer model for solids friction factor has been developed by introducing the collision effect and particle velocity model in the model of solids friction. The results of scale-up validation in larger and longer pipelines for four different products have shown that for the majority of the cases, the new model for solids friction factor has resulted in better predictions in Dense-Phase Flow conditions compared to the predictions obtained by an existing two-layer model.
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On developing improved modelling for particle velocity and solids friction for fluidized Dense-Phase pneumatic transport systems
Powder Technology, 2018Co-Authors: Kapil Sharma, Soumya Suddha Mallick, Anu Mittal, Renhu PanAbstract:Abstract Pneumatic transport of fine powders in fluidized Dense-Phase pneumatic conveying of powders has become popular in several industries because it offers various advantages, such as reduced air Flow and gas velocity, reduced pipeline sizing and wear rate, reduced size requirement of gas–solid separator unit etc. For the reliable design of a pneumatic conveying system precise estimation of the solids friction factor through horizontal straight pipes is essential, but it is a challenging task till date because of the highly concentrated, turbulent, and complex nature of the gas–solids mixture. In the present work, power station fly ash (median particle diameter: 22 μm; particle density: 2370 kg/m3; loose-poured bulk density: 660 kg/m3) and cement (median particle diameter: 19 μm; particle density: 2910 kg/m3; loose-poured bulk density: 1080 kg/m3) were conveyed through different pipeline configurations (i.e., 65-mm inner diameter × 254-m-long and 80/105-mm inner diameter × 407-m-long step-up pipeline). For the fluidized Dense-Phase Flow in pneumatic conveying system, governing equations were developed and the same were solved using fourth-fifth-order Runge-Kutta-Fehlberg (RKF45) method. The results revealed that the particle velocity and actual gas velocity and the ratio of the two velocities increases along the direction of Flow, while an opposite trend was found for the solids volumetric concentration. The particle velocity and actual gas velocity terms were then included in an existing pure dilute-Phase model (for solid friction factor) to modify it, by incorporating sub-models for particle and actual gas velocities and impact and solids friction factor and make it suitable for Dense-Phase mode. The solids friction-factor model was then validated by comparing the experimental and predicted pneumatic conveying characteristics for different solids Flow rates and by using it to predict the total pipeline pressure drops for larger and longer pipelines. The new model has shown reliable predictions in the Dense-Phase region.
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Numerical simulation of fluidized Dense-Phase pneumatic conveying of powders to develop improved model for solids friction factor
Particuology, 2017Co-Authors: Baldeep Kaur, Soumya Suddha Mallick, Anu Mittal, Renhu Pan, Soumendu JanaAbstract:Accurate prediction of the solids friction factor through horizontal straight pipes is important for the reliable design of a pneumatic conveying system, but it is a challenging assignment to date because of the highly concentrated, turbulent, and complex nature of the gas–solids mixture. Power-station fly ash was transported through different pipeline configurations. Numerical simulation of the Dense-Phase pneumatic conveying systems for three different solids and two different air Flow rates have shown that particle and actual gas velocities and the ratio of the two velocities increases in the Flow direction, whereas the reverse trend was found to occur for the solids volumetric concentration. To develop a solids friction-factor model suitable for Dense-Phase Flow, we modified an existing pure dilute-Phase model by incorporating sub-models for particle and actual gas velocities and impact and solids friction factor. The solids friction-factor model was validated by using it for scale-up predictions for total pipeline pressure drops in longer and larger pipes and by comparing experimental and predicted pneumatic conveying characteristics for different solids Flow rates. The accuracy of the prediction was compared with a recently developed two-layer-based model. We discussed the effect of incorporating the particle and actual gas velocity terms in the solids friction-factor model instead of superficial air velocity.
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on developing improved modelling and scale up procedures for pneumatic conveying of fine powders
Powder Technology, 2017Co-Authors: Baldeep Kaur, Peter W Wypych, Soumya Suddha Mallick, Anu Mittal, Soumendu JanaAbstract:Abstract Pneumatic transport of fine powders in fluidized Dense-Phase mode is becoming increasingly popular in various industries, such as power, chemical, cement, refinery, alumina, pharmaceutical, limestone, to list a few, because of the reasons of reduced gas Flow rate and power consumption, decreased conveying velocities, improved product quality control, reduced pipeline sizing and wear rate, increased workplace safety etc. For the reliable design of a pneumatic conveying system, it is important to accurately predict the total pipeline pressure drop. However, accurate prediction of pressure drop from an improved understanding of the fundamental transport mechanism of fluidized Dense-Phase Flow condition has only made limited progress till now because of the highly concentrated and turbulent nature of the gas-solids mixture. Power plant fly ash (median particle diameter: 30 μm; particle density: 2300 kg/m3; loose-poured bulk density: 700 kg/m3) was conveyed through different pipelines (69 mm I.D. × 168 m long; 105 mm I.D. × 168 m long; 69 mm I.D. × 554 m long). 8 different fly ash samples were tested in a fluidizing column for their deaeration characteristics and fluidized bulk densities were determined. Governing equations of Flow for the Dense-Phase pneumatic conveying system of fine powders were solved using Runge-Kutta-Fehlberg (RKF45) method for different fluidized bulk densities of fly ash and air Flow rates. The results have shown that the particle and actual gas velocities and the ratio of the two velocities increase in the direction of Flow, while a reverse trend was apparent for the solids volumetric concentration. The results were compared against the predictions obtained using existing empirical relations for particle velocity. To develop an improved model for solids friction factor, an existing reliable pure dilute-Phase model has been modified for Dense-Phase Flow condition by incorporating sub-models for particle to actual gas velocity and impact and solids friction factor. The developed solids friction factor model was validated by using it to predict the total pipeline pressure drops for larger and longer pipelines and by comparing the experimental and predicted pneumatic conveying characteristics. The results have shown improved reliable predictions and that the model is capable of addressing the gradual transition of Flow mechanism from Dense- to dilute-Phase. The accuracy of prediction is similar (in fact better in certain scale-up cases) when compared to a recently developed two-layer based model (developed by some of the authors). The results demonstrate the importance of incorporating particle and actual gas velocity terms in the model of solids friction factor instead of the prevailing techniques that overly depend on using superficial gas velocities.
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evaluation of scaleup procedures using system approach for pneumatic conveying of powders
Particulate Science and Technology, 2010Co-Authors: Soumya Suddha Mallick, Peter W WypychAbstract:This article presents results from an ongoing research effort aimed towards developing a validated scaleup procedure for pressure drop for the Dense-Phase pneumatic conveying of powders. Two existing/popular forms of the “system” approach for scaling up of diameter were evaluated. The validity of the current technique for length scaleup using a “system” approach was also examined. The existing method showed good potential for dilute-Phase Flow, but resulted in appreciable under-predictions when predicting for Dense-Phase Flow. The effect of bends on the accuracy of the method was also investigated. In this study, steady-state conveying data of four different powders conveyed in various pipes (diameter/lengths) were used for the purpose of scaleup investigations.