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Volume 17, Issue 7
Displaying 1-4 of 4 articles from this issue
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Nobuetsu YUTANI, Naoshi OTOTAKE1980 Volume 17 Issue 7 Pages 367-373
Published: July 10, 1980
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIn this study, for an example of the phenomena controlled by fluctuating motions of particles in the technology with powder processes, the diffusional phenomena of particles have been theoretically discussed about from microscopical structural motions of particles. Attentions have been focussed on the following terms;
(1) The statistical-dynamical understanding of the behavioe of particles as basic considerations on theoretical particle diffusivity.
(2) The derivation of theoretical particle diffusivity using statition function of particle velocity. Concretely, the “cell model” based upon statistical distribution function have been proposed to explain several types of the behavior of randomly moving particles. That is, “Brown's Model” and “Eyring's Model” can be developed on the baees of the motion of individual particle and of groups of particles, respectively. Comparsions have been made between values estimated using these model and experimental data with particle diffusivity in solids-liquid fluidiaed beds.
As a result, it is indicated that theoretical particle diffusivity based upon structural considerations of particle-motions can be explain the diffusional behavior of particles in the bed.View full abstractDownload PDF (820K) -
Keijiro TERASHITA, Kei MIYANAMI, Takeo YANO, Akira IWAZAWA1980 Volume 17 Issue 7 Pages 374-382
Published: July 10, 1980
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe shearing stresses were measured by a shearing tester for the packed bed of several kinds of fine powder. The normal stress distribution aboe and below the shearing plane were also measured.
The characteristics of fine powders were classified in terms of the trend of the shearing process and normal stress distributions.
The internal friction factor (μm, s) was calculated from the steady state value of the measured shearing stress(τx, s) The flowability of powder was discuss in terms of μm, s.
The findings are as follows:
(1) The less the flowability is, the greater the normal stress distribution is. The normal stress (σz, m) averaged over the plane was smaller than the applied normal stress (σz, w). This implied that a part of the applied force may be consumed in the powder bed.
(2) Satisfying Coulomb's law, the σz, m is exactly proportional to the τx, s. The relationship between σz, w and τx, s however slightly deviate of from Coulomb's law.
(3) The relationship between σz, m and τx, s is independent of both the initial voidage and the height of upper powder bed. The internal friction factor μm, s can be explained in terms of the flowability depending on the normal stress distribution.View full abstractDownload PDF (1038K) -
Satoshi OKUDA, Woo Ski CHOI1980 Volume 17 Issue 7 Pages 383-391
Published: July 10, 1980
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThis investigation study was carried out as the cooperate work of members of the grinding group, which was belonged to the Society of Powder Technology in Japan.
The useful data obtained by actual size-reduction equipment being used in various industrial fields was collected and arranged synthetically based on particle size distribution, feed rate, and specific consumed energy. Prior to arrangement of the data, the actual grinding equipment were classified according to principal grinding action in the equipments such as compression or nipping (N-type), impact or blow (I-type), tumbling or projection (T-type), cutting or shredding (C-type), attrition (A-type), and other type equipments.
The following results were obtained:
1) It was confirmed that the particle size distribution of products obtained by each type of size-reduction equipment was almost expressed by the Rosin-Rammler distribution function and the uniformity of R-R distribution function became large in small dgree as the particle size of products was increased.
2) The specific energy consumption was reduced as the feed rate was increased. This fact indicates that the scale-up of grinding equipment improves the energy efficiency and reduces the running cost of grineing process.
3) The relation between the specific energy consumption and particle size of products was generally expressed by a simple formula. This relation may be available to the design of grinding equipments and test of performance of them.View full abstractDownload PDF (819K) -
Yoichi Nagase, Kenji Okada1980 Volume 17 Issue 7 Pages 392-400
Published: July 10, 1980
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (981K)
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