The Experts below are selected from a list of 186 Experts worldwide ranked by ideXlab platform
Mooson Kwauk - One of the best experts on this subject based on the ideXlab platform.
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aggregative and Particulate Fluidization the two extremes of a continuous spectrum
Chemical Engineering Science, 1996Co-Authors: Dejin Liu, Mooson KwaukAbstract:Solid particles belonging to Geldart Group A, B and D were fluidized in liquids of changing viscosity and in CO2 under ambient to supercritical conditions. Local bed voidage signals were collected and processed in conjunction with global expansion characteristics to give quantitative indexes for evaluating Fluidization quality. Results showed that the fluidized state changes progressively from aggregative to Particulate when fluidized separately by gas, supercritical fluid and liquids, indicating an infinite number of intermediate states existing between aggregative and Particulate Fluidization. A discrimination number Dn is proposed to describe the transition from Particulate to aggregative. A heterogeneity index δ and a nonideality index fh are proposed to quantify, respectively, the local and the global characteristics of the intermediate states.
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Aggregative and Particulate Fluidization—The two extremes of a continuous spectrum
Chemical Engineering Science, 1996Co-Authors: Dejin Liu, Mooson KwaukAbstract:Solid particles belonging to Geldart Group A, B and D were fluidized in liquids of changing viscosity and in CO2 under ambient to supercritical conditions. Local bed voidage signals were collected and processed in conjunction with global expansion characteristics to give quantitative indexes for evaluating Fluidization quality. Results showed that the fluidized state changes progressively from aggregative to Particulate when fluidized separately by gas, supercritical fluid and liquids, indicating an infinite number of intermediate states existing between aggregative and Particulate Fluidization. A discrimination number Dn is proposed to describe the transition from Particulate to aggregative. A heterogeneity index δ and a nonideality index fh are proposed to quantify, respectively, the local and the global characteristics of the intermediate states.
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Particulate Fluidization: An Overview
Advances in Chemical Engineering Volume 17, 1991Co-Authors: Mooson KwaukAbstract:Publisher Summary The fluidity of a liquid or a gas has its origin in the mobility against one another of the constituent molecules. Solid particles may be pushed apart from one another to acquire this mobility by the steady upflow of a liquid or a gas at sufficient velocity. When this fluid flow starts at a relatively low velocity through a static bed of solid particles, the interstitial pores among the particles offer sufficient resistance to the fluid to create a corresponding drop in pressure in the direction of flow. Solid particles can also be fluidized by mechanical vibration, or in the case of ferromagnetic particles, by application of an appropriate alternating magnetic field. Thus, the achievement of the fluidized state ought to be considered in terms of all possible motivating forces or the combination of these forces, rather than being limited to upward fluid flow alone. Fluid flow tends to carry a particle in the direction of the surrounding flowing fluid. There is a layer of fluid around the particle that transmits the shear produced by the moving fluid to act on the particle being pushed. When the rate of flow is high, the fluid also carries a kinetic pressure against those parts of the particle that present a frontal area facing the flowing fluid. Solids in particle–fluid systems in motion tend to segregate from their dissimilar neighbors and to coexist with their kin under similar conditions. Once segregated, however, they tend to disperse into enclaves occupied by those dissimilar neighbors by a mechanism similar to diffusion. Idealization of Particulate Fluidization provides the essential concept towards a basic understanding of fluid–particle systems.
R.k. Singh - One of the best experts on this subject based on the ideXlab platform.
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Published in Powder Technology, 2005
2015Co-Authors: R.k. Singh, G K RoyAbstract:Prediction of minimum bubbling velocity, Fluidization index and range of Particulate Fluidization for gas–solid Fluidization in cylindrical and non-cylindrical bed
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Hydrodynamic studies of gas-solid Fluidization in hexagonal bed for non-spherical particles
Journal of Scientific & Industrial Research, 2009Co-Authors: Saroj K. Padhi, R.k. SinghAbstract:This paper presents hydrodynamic properties (minimum Fluidization velocity, pressure drop at minimum Fluidization, minimum bubbling velocity, minimum slugging velocity, Particulate Fluidization, bubbling Fluidization, expansion ratio, fluctuation ratio etc.) of gas solid Fluidization in hexagonal bed. Experimental values of these properties in hexagonal bed have been compared with corresponding values in cylindrical bed.
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Prediction of minimum bubbling velocity, Fluidization index and range of Particulate Fluidization for gas–solid Fluidization in cylindrical and non-cylindrical beds
Powder Technology, 2005Co-Authors: R.k. SinghAbstract:A uniform Fluidization exists between minimum Fluidization velocity and minimum bubbling velocity. Experimental investigations have been carried out for determination of minimum bubbling velocity and Fluidization index for non-spherical particles in cylindrical and non-cylindrical beds. In the present paper equations have been developed for the prediction of minimum bubbling velocity for gas–solid Fluidization in cylindrical and non-cylindrical (viz. semi-cylindrical, hexagonal and square) beds for non-spherical particles fluidized by air at ambient conditions. A fairly good agreement has been obtained between calculated and experimental values. Based on the experimental data it is concluded that under similar operating conditions minimum bubbling velocity and the Fluidization index are maximum in case of either semi-cylindrical conduit or hexagonal conduit for most of the operating conditions and minimum in case of square one. It is further observed that the range of uniform (Particulate) Fluidization is maximum in case of semi-cylindrical bed for identical operating conditions.
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prediction of minimum bubbling velocity Fluidization index and range of Particulate Fluidization for gas solid Fluidization in cylindrical and non cylindrical beds
Powder Technology, 2005Co-Authors: R.k. Singh, G K RoyAbstract:A uniform Fluidization exists between minimum Fluidization velocity and minimum bubbling velocity. Experimental investigations have been carried out for determination of minimum bubbling velocity and Fluidization index for non-spherical particles in cylindrical and non-cylindrical beds. In the present paper equations have been developed for the prediction of minimum bubbling velocity for gas–solid Fluidization in cylindrical and non-cylindrical (viz. semi-cylindrical, hexagonal and square) beds for non-spherical particles fluidized by air at ambient conditions. A fairly good agreement has been obtained between calculated and experimental values. Based on the experimental data it is concluded that under similar operating conditions minimum bubbling velocity and the Fluidization index are maximum in case of either semi-cylindrical conduit or hexagonal conduit for most of the operating conditions and minimum in case of square one. It is further observed that the range of uniform (Particulate) Fluidization is maximum in case of semi-cylindrical bed for identical operating conditions.
Jingsi Yang - One of the best experts on this subject based on the ideXlab platform.
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Agglomerating vibro-Fluidization behavior of nano-particles
Advanced Powder Technology, 2009Co-Authors: Jingsi Yang, Tao Zhou, Lianying SongAbstract:Abstract An experiment study of agglomerating Fluidization behavior of three kinds of nano-particles (SiO 2 , TiO 2 , ZnO) in vibro-fluidized bed (VFB) has been performed. At certain amplitude (3 mm) of vibrations applied, the minimum Fluidization velocity decreases, whilst the equilibrium pressure drop increases with increase in the vibration frequency. The minimum Fluidization velocity is nearly independent of the vibration amplitude at almost constant frequency of about 40 Hz, whilst the equilibrium pressure increases. Using the linear regression, the Richardson–Zaki exponents of three kinds of nano-particles have been calculated. R–Z analyses indicate that the Particulate Fluidization degree of cohesive particles can be greatly improved by vibration force.
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Behavior of mixtures of nano-particles in magnetically assisted fluidized bed
Chemical Engineering and Processing: Process Intensification, 2008Co-Authors: Ping Zeng, Tao Zhou, Jingsi YangAbstract:Abstract Gas-Fluidization of nano-particle mixtures in magnetically assisted fluidized bed (MAFB) has been investigated. Nano-particles undergoing Fluidization exhibit two types of behavior: agglomerate Particulate Fluidization (APF) and agglomerate bubbling Fluidization (ABF). Fluidization of sole SiO2 or ZnO nano-particles exhibits APF and ABF, respectively, but mixtures of them can be fluidized stably and almost homogenously. Stable Fluidization of nano-particle mixtures can be achieved by variations in both the field intensity and the initial mixture content. Simple analytical model is developed to predict the apparent terminal velocity of the mixture of APF and ABF nano-particles, and the calculated values are in agreement with the experimental data.
Limin Wang - One of the best experts on this subject based on the ideXlab platform.
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unified stability condition for Particulate and aggregative Fluidization exploring energy dissipation with direct numerical simulation
Particuology, 2013Co-Authors: Min Wei, Limin WangAbstract:Fully resolved simulations of Particulate and aggregative Fluidization systems are performed successfully with the so-called combined lattice Boltzmann method and time-driven hard-sphere model (LBM-TDHS). In this method, the discrete particle phase is described by time-driven hard-sphere model, and the governing equations of the continuous fluid phase are solved with lattice Boltzmann method. Particle-fluid coupling is implemented by immersed moving boundary method. Time averaged flow structure of the simulated results show the formation of core-annulus structure and sigmoid distribution of voidage in the axial direction, which are typical phenomena in Fluidization systems. Combining the results of the simulation, the energy consumption N-st for suspending and transporting solids is calculated from the direct numerical simulation (DNS) of Fluidization, and the stability criterion N-st/N-T = min proposed in EMMS/bubbling model is verified numerically. Furthermore the numerical results show that the value of N-st/N-T in Particulate Fluidization is much higher than that in aggregative Fluidization, but N-st/N-T = min is effective for both Particulate and aggregative Fluidization. (C) 2012 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.
Tao Zhou - One of the best experts on this subject based on the ideXlab platform.
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Fluidization behavior of binary mixtures of nanoparticles in vibro-fluidized bed
Advanced Powder Technology, 2014Co-Authors: Xizhen Liang, Hao Duan, Tao Zhou, Jiangrong KongAbstract:Abstract The Fluidization behavior of different mixed SiO 2 , TiO 2 and/or ZnO nanoparticles under the application of vibrated fields of constant vibrated frequencies (40 Hz) and amplitude (3.0 mm) is studied. The single nanoparticles experiments show that SiO 2 nanoparticles have a better Fluidization quality than TiO 2 and ZnO nanoparticles. For binary mixtures of the nanoparticles, the amount of SiO 2 nanoparticles generally has a beneficial effect on the Fluidization quality of the binary mixtures. Using the linear regression, the Richardson–Zaki exponents of three kinds single and their binary mixture of nanoparticles are calculated. The Richardson–Zaki analyses indicate that the Particulate Fluidization degree of mixed nanoparticles can be greatly improved in agglomerate Particulate Fluidization (APF) behavior.
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Agglomerating vibro-Fluidization behavior of nano-particles
Advanced Powder Technology, 2009Co-Authors: Jingsi Yang, Tao Zhou, Lianying SongAbstract:Abstract An experiment study of agglomerating Fluidization behavior of three kinds of nano-particles (SiO 2 , TiO 2 , ZnO) in vibro-fluidized bed (VFB) has been performed. At certain amplitude (3 mm) of vibrations applied, the minimum Fluidization velocity decreases, whilst the equilibrium pressure drop increases with increase in the vibration frequency. The minimum Fluidization velocity is nearly independent of the vibration amplitude at almost constant frequency of about 40 Hz, whilst the equilibrium pressure increases. Using the linear regression, the Richardson–Zaki exponents of three kinds of nano-particles have been calculated. R–Z analyses indicate that the Particulate Fluidization degree of cohesive particles can be greatly improved by vibration force.
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Behavior of mixtures of nano-particles in magnetically assisted fluidized bed
Chemical Engineering and Processing: Process Intensification, 2008Co-Authors: Ping Zeng, Tao Zhou, Jingsi YangAbstract:Abstract Gas-Fluidization of nano-particle mixtures in magnetically assisted fluidized bed (MAFB) has been investigated. Nano-particles undergoing Fluidization exhibit two types of behavior: agglomerate Particulate Fluidization (APF) and agglomerate bubbling Fluidization (ABF). Fluidization of sole SiO2 or ZnO nano-particles exhibits APF and ABF, respectively, but mixtures of them can be fluidized stably and almost homogenously. Stable Fluidization of nano-particle mixtures can be achieved by variations in both the field intensity and the initial mixture content. Simple analytical model is developed to predict the apparent terminal velocity of the mixture of APF and ABF nano-particles, and the calculated values are in agreement with the experimental data.