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Volume 31, Issue 10
Displaying 1-9 of 9 articles from this issue
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Tetsuo AKIYAMA, Motomi KONO1994 Volume 31 Issue 10 Pages 698-702
Published: October 10, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThis paper is concerned with the displacement of powder beds in an inclined vessel. The displacement was induced by an impact stress applied at the bottom of the vessel by an air hammer. The effects of the intensity of the impact stress, the bed height and the angle of vessel inclination on the bed displacement were investigated. The angle of vessel inclination was found to be by far the most dominant factor in determining the extent of powder bed displacement. This suggests that hopper geometry is the key to ensuring the reliable and efficient operation of the solid discharge.View full abstractDownload PDF (533K) -
Toshihiko UMEKAGE, Shinichi YUU1994 Volume 31 Issue 10 Pages 703-710
Published: October 10, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSParticle trajectories and collision efficiencies have been computed for unequally-sized fine particles settling in air, taking into account their hydrodynamic interaction and interparticle attraction. In the continuum, the resistance force of one particle moving towards another increases as the separation distance between particles decreases and becomes infinite just before touching. However, the resistance force of a fine particle diameter of which is less than several dozen microns does not increase infinitely in air because the air between two colliding particles the Knudsen number of which is more than 10-3 behaves like a discontinuum. Thus, a fine particle in air would collide with another particle more easily. In this study, experimental data on the resistance force of a particle in the discontinuum was applied to the resistance coefficient of particles in air. The calculated results indicate that the calculated collision efficiency of a fine particles in air is 1.5-8 times larger than that based upon the continuum theory.View full abstractDownload PDF (932K) -
Mitsuo KAMIWANO, Meguru KAMINOYAMA, Kazuyoshi ARAI, Takeshi AMARI1994 Volume 31 Issue 10 Pages 711-718
Published: October 10, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIn this study, a method is proposed for instantaneously measuring the diameter distribution of particles having an irregular shape using a real-time image processing system, which the authors developed.
The system has a real-time signal circuit. It simultaneously processes all of the signals output from many phototransistors (PT) used as a sensor without a conventional image scanner to eliminate measurement errors due to scanning time.
The method proposed here enabled one to measure the individual shape of each particle and to indicate the particle diameter by multi-directionally capturing shadows of the particle flying independently in a jet of gas with a transmitted light-system mode. The method solved the problems of the overlapping of particles and the need for enormous labor to do measurements, which conventional methods such as photographs have. It enables one also to obtain a number of particle diameters and their distribution in a very short time.View full abstractDownload PDF (2366K) -
Discrimination between Particle-particle and Particle-wall InteractionShuji MATSUSAKA, Kouichi MIZUMOTO, Masanori KOUMURA, Hiroaki MASUDA1994 Volume 31 Issue 10 Pages 719-725
Published: October 10, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe adhesive strength distributions of particles were experimentally evaluated based on the reentrainment phenomena. Fully dispersed fine aerosol particles were deposited on a test piece, and the particle reentrainment tests were carried out in an air-flow channel. Then, the relationships between reentrainment efficiency and the corresponding wall shear stress were obtained. Two kinds of adhesive strength distribution were found to be obtained from the reentrainment efficiency curve:one is related to particle-wall interaction (adhesion), and the other is related to particle-particle interaction (cohesion). They were caused by the reentrainment of primary particles and agglomerated particles, respectively. Both of the two kinds of adhesive strength distribution were represented by a log-normal distribution and were evaluated based on the geometric mean and the geometric standard deviation. Further-more, the mass fraction of reentrained agglomerated particles was well represented by a simple equation derived from the analysis of the reentrainment phenomena.View full abstractDownload PDF (3742K) -
Kuniaki GOTOH, Kenta KARUBE, Hiroaki MASUDA, Yoshiji BANBA1994 Volume 31 Issue 10 Pages 726-733
Published: October 10, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSNew methods of fine particle-removal have been developed based on a high-speed air-jet. One of the newly developed methods utilized the precharging of the surface by a needle-like electrode. It was confirmed that the method was effective for the removal of particles that adhered both to the glass and copper surfaces. Also, it was revealed that an agglomeration of particles on these surfaces was induced by pre-charging; i. e. spherical agglomerated particles were formed on the glass surface, and layered agglomerations were formed on the copper surface. These agglomerations enhanced the removal through the increase in removal force by the airflow.
Vibrating air-jet removal, which was another method tested, was also effective for fine particle removal. The removal efficiency was further improved by using both the pre-charging and the vibrating air-jet achieving almost 90% removal of 1μm particles.View full abstractDownload PDF (3831K) -
Shigemi OKANISHI1994 Volume 31 Issue 10 Pages 734-737
Published: October 10, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (1993K) -
Koutarou IIDA1994 Volume 31 Issue 10 Pages 747-749
Published: October 10, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (311K) -
Kei MIYANAMI1994 Volume 31 Issue 10 Pages 750-753
Published: October 10, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (3420K) -
Ko HIGASHITANI1994 Volume 31 Issue 10 Pages 754
Published: October 10, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (124K)
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