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Volume 27, Issue 7
Displaying 1-7 of 7 articles from this issue
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Kenichi USHIKI, Shinichi YUU, Seiji HANATANI1990 Volume 27 Issue 7 Pages 450-456
Published: July 10, 1990
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSGas velocity distributions around a collector of a large aspect ratio were estimated at different Reynolds numbers from 10 up to 10000. The leading edge separation bubble sizes that were obtained agreed well with the results observated in the literature. The fluctuation in the calculated collection efficiency due to unsteady flow at a high Reynolds number remained witin 16%. The inertial collection efficiency increased with the increase in the Reynolds number, and some increase was even recognized when the Reynolds number was beyond 1000.
Gas velocity distributions around a prism with a medium aspect ratio 0.4 were also calculated at different Reynolds numbers 2, 10 and 50. Although inertial collection efficiencies increased with the increase in the Reynolds number, the increase was found to be slight at Reynolds numbers beyond 10. Inertial collection efficiencies were also found to increase as the aspect ratio increases.
The effects of the Reynolds number and aspect ratio on the gravitational collection efficiency were found to be insignificant. The calculated collection efficiencies were verified experimentally,View full abstractDownload PDF (877K) -
Keijiro TERASHITA, Kiminori UMEDA, Kei MIYANAMI1990 Volume 27 Issue 7 Pages 457-462
Published: July 10, 1990
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSA study of the improvement of the flowability of particles by a dry coating method was performed. With corn starch as source particles and silica as lubricant particles, experiments were carried out with Angmill at various rotation speeds and treatment times. The flowability was evaluated by the angle of repose, compressibility and discharge speed of particles. In addition, the electrifications of the particles were investigated.
It was found that the composite particles with superior flowability were obtained when the lubricant particles were well-dispersed and coated on the source particles. In this case, surface modification of the source particles confirmed. It was confirmed that particles of surerior flowability were not obtained from either weak mechanical energy (shearing, compression) causing bad dispersion of the lubricant particles or excessive energy causing the burial of the lubricant particles in the source particles.
Subsequently, it was possible to model the process of surface modification by the dry coating method. In addition, it was indicated that the Angmill is a useful mixer for mixing fine powder.View full abstractDownload PDF (2173K) -
Mitsuo SAMATA1990 Volume 27 Issue 7 Pages 463-469
Published: July 10, 1990
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe investigation for errors due to anisokinetic sampling on particle concentration measurement was conducted with talc and fly-ash particles of sizes in the range of 1-20μm, and also used with several dusts which were emitted from an oil combustion boiler, an alumina kiln and from a glass smelting furnace, respectively. The equation which can be widely applied for Stokes number Sk between 0.1 and 30 was derived from the results. The empirical equation obtained is, Cs/Co=α(Vo/VS)+(1-α), where, Co is the particle concentration in isokinetic sampling, Cs is one in anisokinetic sampling, Vo is the gas velocity in the duct, and VS is gas suction velocity. Inertia function α in the equation is decided with the values of Sk, Vo/VS and Ao. Although Ao is a coefficient correlated to Sk and Vo/VS in a rigorously practical definition, Values of Ao are approximately 1 in fine particles and 0.0625 in coarse ones respectively. It was presumed that a specific thin boundary layer was generated into stream of anisokinetic suction. Thus, it is assumed that the marginal gas velocity in the layer not only increased suddenly, but also decreased according to the values of Vo/Vs.View full abstractDownload PDF (3451K) -
Shuhei SHIOJI, Hideo YAMAMOTO1990 Volume 27 Issue 7 Pages 470-475
Published: July 10, 1990
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSSurface alkoxyl reaction of silica gels was investigated under ordinary contact with some of the low molecular weight saturated aliphatic alcohols. Silica gels were in contact with liquid alcohols by using Soxhlet's extractor below their boiling points. The degree of alkoxylation for surface hydroxyls was examined by an infrared spectra and with T. G, analysis. It was shown that some of the surface hydroxyls were easily esterified to alkoxyl groups even by contact with alcohols under ordinary conditions.
Adsorption isotherms of methanol vapor at room temperature (25°C) were measured on silica samples which were previously activated at various temperatures. Adsorption equilibria depend upon the pre-treated temperature, and surface methylation reaction took place not only on surface hydroxyls but also on siloxane bridges even at room temperature.View full abstractDownload PDF (665K) -
Mitsuaki OCHI1990 Volume 27 Issue 7 Pages 476-479
Published: July 10, 1990
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (417K) -
Coating Technology on the Surface of ParticlesEiki TAKESHIMA1990 Volume 27 Issue 7 Pages 480-484
Published: July 10, 1990
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (6896K) -
Tatsuo TANAKA1990 Volume 27 Issue 7 Pages 490-492
Published: July 10, 1990
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (1942K)
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