Modeling and Analysis of Solids Friction Factor for Fluidized Dense Phase Pneumatic Conveying of Powders

Behera, Niranjana; Agarwal, Vijay K.; Jones, Mark; Williams, Kenneth C.

doi:10.1080/02726351.2012.672544

Cited by 17 publications

(10 citation statements)

References 9 publications

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“…Comparatively, relatively more success based on fundamental modelling methods using powder mechanics have been developed for low-velocity slug-flow of granular products [4] or the dilute-phase flow of bulk solids flow mechanics can be considered to be applicable with a fair accuracy [5]. Because of the limited progress achieved so far in fundamentally understanding the transport mechanisms of fluidized bulk solids, empirical power function based models have been popularly developed over the years by several investigators for important design parameters, such as minimum transport (to predict flow blockage condition) and solids friction factor (to determine pressure drop in pipes) [2,[6][7][8][9][10]. These models [2,[6][7][8][9][10] have shown good predictions when applied to researchers' own data, but previous investigation [2] has demonstrated that the empirical models can unexpectedly result in significant inaccuracy under scale-up conditions of pipeline length and diameter.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…The existing models are based on dimensionless numbers, such as particle and gas based Froude number, volumetric loading ratio etc. [2,[6][7][8][9][10], but these have not taken into [1]. Most of the existing models for solids friction factor or minimum transport criteria include mass or volumetric flow ratios, but these do not consider the nature of the dunes.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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Stability and phase space analysis of fluidized-dense phase pneumatic transport system

et al. 2018

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Section: Accepted Manuscriptmentioning

confidence: 99%

Section: Accepted Manuscriptmentioning

confidence: 99%

Stability and phase space analysis of fluidized-dense phase pneumatic transport system

et al. 2018

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“…Mallick and Wypych (2007) used particle-gas density ratio in the solid friction factor correlation and the error of predicted solid friction factor with respect to experimental data was very low (R 2 = 0.998). Behera et al (2013) expressed equation of a solid friction factor in terms of Froude number and solids loading ratio including coefficient and exponents. The unknown coefficient and exponents were calculated by solving the flow equations.…”

Section: Introductionmentioning

confidence: 99%

“…But most of the existing solid friction factor correlations show large error in predicting the pressure drop for different pipeline configurations. Equation developed by Behera et al (2013) was having different values of coefficient and exponents for each of the conveying materials used. In the scaleup conditions (63-mm diameter pipeline and 221-m equivalent pipeline length), predicted pressure drop was within the acceptable error margin for only one data out of two experimental data.…”

Section: Introductionmentioning

confidence: 99%

Modelling and analysis of flow of powders through long pipelines

Shijo

Behera

2020

WJE

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Purpose The purpose of this paper is to focus on predicting the pressure drop in fluidized dense phase pneumatic conveying of fine particles through pipelines by modelling the solids friction factor in terms of non-dimensional parameters using experimental data of definite pipeline configuration. Finally, the model is to be tested for a different pipeline configuration. Design/methodology/approach Solids friction factor has been expressed in terms of certain non-dimensional parameters such as density ratio, solids loading ratio and mean particle diameter to pipe diameter ratio, and a certain number of coefficients and exponents. Experimental data of five conveying materials (two types of fly ash, two types of alumina and one type of cement meal) for a pipeline configuration of diameter 53 mm and length 173 m and another conveying material EPS dust for two pipeline configurations (69-mm diameter, 168-m long; 105-mm diameter, 168-m long) have been used to calculate the unknown coefficients or exponents of the mathematical model for solids friction factor. Findings The developed model gives the best results in predicting the pressure drop for the pipelines that are less than 173-m long, but the model shows a large error for the pipelines more than 173-m long. Research limitations/implications Current research will be helpful for the researchers to model the process of pneumatic conveying through long distances. Practical implications The method will be helpful in conveying powder materials through long distances in cement or brick industry, alumina industry. Social implications Fly ash piles over at the nearby places of thermal power plants. Pneumatic conveying is the best method for transporting the fly ash from the location of power plants to the nearby brick industries or cement industries. Originality/value Solid friction factor has been presented in terms of four non-dimensional parameters and evaluated the accuracy in predicting the pressure drop for two different pipeline configurations.

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“…The aim of this paper is to solve governing equations for gas-solids flows (under dense-phase condition) for important parameters such as particle and actual gas velocities and make use of these parameters in developing reliable scale-up validated model for solids friction factor. Some studies using numerical methods have been carried out in recent times [17,18]. One-dimensional model including particle size distribution was developed [19] to simulate the pneumatic conveying of fine powders through straight pipelines.…”

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confidence: 99%

On developing improved modelling and scale-up procedures for pneumatic conveying of fine powders

et al. 2017

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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/m 3 ; loose-poured bulk density: 700 kg/m 3 ) was conveyed through different pipelines (69 mm I.D. x 168 m long; 105 mm I.D. x 168 m long; 69 mm I.D. x 554 m long). 8 different fly ash samples were tested in a fluidizing column for their deaeration characteristics and fluidized bulk densities *Revised Manuscript Click here to view linked References 2 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 twolayer 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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Modeling and Analysis of Solids Friction Factor for Fluidized Dense Phase Pneumatic Conveying of Powders

Cited by 17 publications

References 9 publications

Stability and phase space analysis of fluidized-dense phase pneumatic transport system

Stability and phase space analysis of fluidized-dense phase pneumatic transport system

Modelling and analysis of flow of powders through long pipelines

On developing improved modelling and scale-up procedures for pneumatic conveying of fine powders

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