An investigation into flow mode transition and pressure fluctuations for fluidized dense-phase pneumatic conveying of fine powders

作     者：A.Mittal S.S.Mallick P.W.Wypych 

作者机构：Department of Mechanical EngineeringThapar UniversityPatialaPunjab 147004India Faculty of Engineering and Information SciencesUniversity of WollongongWollongongNSW 2500Australia 

出 版 物：《Particuology》 (颗粒学报（英文版）)

年 卷 期：2014年第12卷第5期

页      面：187-195页

核心收录：

学科分类：081704[工学-应用化学] 0817[工学-化学工程与技术] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 081701[工学-化学工程] 0703[理学-化学] 0702[理学-物理学] 

主　　题：Fluidized dense phase Pneumatic conveying Fine powders Shannon entropy Flow transition Particle turbulence 

摘      要：This paper presents the results of an ongoing investigation into the fluctuations of pressure signals due to solids-gas flows for dense-phase pneumatic conveying of fine powders. Pressure signals were obtained from pressure transducers installed along different locations of a pipeline for the fluidized dense-phase pneumatic conveying of fly ash （median particle diameter 30μm; particle density 2300 kg/m^3; loose- poured bulk density 700 kg/m^3） and white powder （median particle diameter 55 p.m; particle density 1600 kg/m^3 ; loose-poured bulk density 620 kg/m^3） from dilute to fluidized dense-phase. Standard deviation and Shannon entropy were employed to investigate the pressure signal fluctuations. It was found that there is an increase in the values of Shannon entropy and standard deviation for both of the prod- ucts along the flow direction through the straight pipe sections. However, both the Shannon entropy and standard deviation values tend to decrease after the flow through bend（s）, This result could be attributed to the deceleration of particles while flowing through the bends, resulting in dampened particle fluctua- tion and turbulence. Lower values of Shannon entropy in the early parts of the pipeline could be due to the non-suspension nature of flow （dense-phase）, i.e., there is a higher probability that the particles are concentrated toward the bottom of pipe, compared with dilute-phase or suspension flow （high velocity）, where the particles could be expected to be distributed homogenously throughout the pipe bore （as the flow is in suspension）. Changes in straight-pipe pneumatic conveying characteristics along the flow direction also indicate a change in the flow regime along the flow.