KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 6 , Issue 4
Showing 1-17 articles out of 17 articles from the selected issue
  • Toshiro Maruyama, Fuminao Watanabe, Tokuro Mizushina
    1980 Volume 6 Issue 4 Pages 327-333
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The pipeline mixing of two fluid streams at an oblique branch was studied to clarify the optimum condition for rapid mixing. The optimum condition as a function of branch angle was experimentally obtained by comparing the varying degrees of a standard deviation of the temperature distribution in the downstream cross-section of the pipe. The condition is discussed on the basis of an empirical trajectory of the deflected jet formed by an injection of secondary flow. The branch-angle dependence of mixing is discussed through comparison of the results at the optimum velocity ratio and through application of one-dimensional analysis of the deflected jet.
    As a result, the optimum condition and the jet trajectory were correlated by extending the equations for tee mixing. At the optimum condition for rapid mixing, the jet of the same sign of branch angle shows an almost constant trajectory in its downstream region. The branch-angle dependence of mixing is caused by the jet in the initial stage, and the change in mixing distance from that of optimal tee mixing amounts to the value of the main-pipe diameter. For rapid mixing, a branch angle of about π/4 rad pointed upstream is recommended.
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  • Shiro Ito, Kohei Ogawa, Chiaki Kuroda
    1980 Volume 6 Issue 4 Pages 334-338
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The axial static pressure drop at a wall and the radial distributions of static pressure in swirling pipe flow were investigated on the basis of the Navier-Stokes equation.
    It became clear that a characteristic relationship between the dimensionless axial static pressure drop at a wall ΔPw* and the dimensionless factor (Z/R) · (υ/RUi) was obtained in the range of about Re> 5, 000, which was considered to be the range of complete turbulent swirling flow. An imaginary inlet position based on decay of the intensity of swirl was confirmed to be applicable as a basic position for static pressure at a wall. A method of calculating the radial distributions of static pressure is proposed with experimental data of static pressure at a wall, mean flow velocity and turbulent intensity, on the basis of the turbulent Navier-Stokes equation, and several pressure distributions are shown.
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  • Katsuhiro Nozawa
    1980 Volume 6 Issue 4 Pages 339-344
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The following experimental equations of the relationships between maximum local Nusselt number Nu0 and mean Nusselt number NUm, and Reynolds number Re are obtained for the fusion of cylindrical ice in jetted moist air within the region of Reynolds number Re from 3, 000 to 120, 000.
    Nu0=2.9Re0.48
    NUm=0.73Re0.58
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  • Kenkichi Izumi, Akira Yamada, Toshio Sawa, Sankichi Takahashi
    1980 Volume 6 Issue 4 Pages 345-351
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The formation of iron sludge in a multi-stage flash evaporation plant for desalination of sea water was studied by using a 100 m3/d plant and an experimental apparatus.
    From the mass balance of iron in the plant, it was found that most of the iron in the sludge was in corrosion products of the evaporator shell, made from steel. The iron sludge was a mixture of Fe3O4 and γ-FeOOH, and its composition varied with its temperature in the brine. The major component of the sludge was Fe3O4 at temperatures above 80°C and γ-FeOOH at temperatures below 35°C.
    The mechanism of iron sludge formation was clarified as follows. Particles of the iron compound, Fe (OH) 2 or Green rust (I), were formed as corrosion products of the shell. These particles were suspended in the brine and flowed through the tube. The sludge particles deposited on the surface of the tubes and then changed their forms according to their oxidation temperatures.
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  • Akira Ito, Koichi Asano
    1980 Volume 6 Issue 4 Pages 352-358
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Measurements of simultaneous heat and mass transfer in binary distillation of the methanol-water and the ethanol-water systems at total reflux were made with a small vertical flat-plate wetted-wall column.
    A new theoretical approach was used which takes into account the effect of bulk flow caused by the mass fluxes of the more-and the less-volatile component on the rate of heat and mass transfer in the binary distillation. From measurements of the vapor-phase temperature profiles during binary distillation, the individual vapor-and liquid-phase resistances were evaluated so as to show that the former was controlling. Observed vapor-phase sensible heat fluxes and diffusion fluxes were compared with theoretical values by a laminar boundary layer theory with mass injection or suction at the interface and showed good agreement.
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  • Wataru Eguchi, Motonari Adachi, Takuya Kitabata, Nobuyuki Matsuka
    1980 Volume 6 Issue 4 Pages 359-365
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The change of light absorbance profiles in the liquid phase with time was directly measured by using a position-scanning spectrophotometer in the case of non-steady absorption of iodine vapor contained in air.
    The absorbance profiles measured at different wavelengths were proportional to each other when an aqueous HClO4 solution was used as the absorbent liquid, confirming that the only species of iodine present in the liquid phase was the molecular one, i.e., confirming the physical dissolution and diffusion of I2 in the liquid phase. On the other hand, for aqueous NaOH-H3BO3 mixture solutions, the light absorbance profiles at different wavelengths were different in shape, showing the presence of other iodine species due to the reactions of molecular iodine absorbed into the liquid phase. Furthermore, the difference between absorption with instantaneous chemical reactions and that with non-instantaneous reactions was clearly distinguished. From the analysis of the concentration profiles determined from the observed absorbance profiles, the absorption mechanism of iodine vapor was ascertained.
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  • Yukimichi Okamoto, Kenji Yamaguchi
    1980 Volume 6 Issue 4 Pages 366-371
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Performance of metal sponge plates as baffles in a pulse column was examined as compared with perforated plates. Values of HETS were measured at various conditions of pulse amplitude, flow rate, flow rate ratio, and with metal sponge plates of various dimensions. The extraction system employed was MIBK-acetic acid-water.
    When nickel sponge plates of porosity 91%, foam dia. 3 mm and thickness 10 mm were set at a plate spacing of 50 mm, an efficiency of HETS = 0.17-0.55 m was obtained, while the perforated plate column operated at the same conditions provided the value of HETS = 0.17-0.58 m. For these two kinds of baffles, the dependency of HETS on flow rate and its ratio were approximately the same, but the dependency on pulse amplitude was somewhat different.
    An advantage of metal sponge plates is that pressure drop and energy dissipation due to the baffles are much smaller. For example, by using metal sponge plates of appropriate foam size, thickness and spacing, the pressure drop could be reduced to as little as 1/3-1/10 of that for perforated plates, with the same value of HETS = 0.22 m.
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  • Kazuo Miyake, Tasuku Nakai
    1980 Volume 6 Issue 4 Pages 372-377
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    To clarify the mechanism of the washing of adhesive mother liquor around crystals by reflux liquor in the purifying section of a fractions crystallizer, four kinds of fractional crystallizer were examined for purifying properties, using benzene-cyclohexane mixture with batchwise operation.
    Experimental results showed that axial back-mixing of solution can be depressed and that the mass transfer rate of contaminant species between adhesive mother liquor and reflux liquor can be promoted by the construction of a suitable mechanism. From such a viewpoint, the crystal packed bed type fractional crystallizer is most favorable.
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  • Toyomitsu Shimizu, Osamu Imai, Yasuhito Sakakibara, Tetsuya Ohrui
    1980 Volume 6 Issue 4 Pages 378-384
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The following three reaction models were examined for the catalytic oxidation of ammonia over a platinum gauze pad.
    I plug flow-diffusion control
    II dispersion flow-diffusion control
    III dispersion flow-diffusion reaction control
    Judging from conformity with industrial reactor performance, III is the most proper model for the catalytic oxidation of ammonia.
    With this model, the effect of reaction temperature on ammonia conversion and the relationship between required gauze numbers and operating condition can be logically explained.
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  • Toyomitsu Shimizu, Osamu Imai, Yasuhito Sakakibara, Tetsuya Ohrui
    1980 Volume 6 Issue 4 Pages 385-391
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Using the dispersion flow-diffusion reaction control model, optimization of the above reaction is studied.
    The following complex reaction scheme is proposed.
    NH3+O2→NO→N2, O2→+NH3→N2, H2O
    Rate equations for the side reactions are determined and a method of calculating the yield of nitrogen oxide, which is the desired product, is developed.
    Defining the yield of nitrogen oxide as the objective function, the qualitative effect of feed gas temperatures, gas mass velocities and space velocities on the objective function are studied. Optimum design and operating conditions are discussed.
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  • Hiroshi Moritomi, Shigekatsu Mori, Kazuo Araki, Akira Moriyama
    1980 Volume 6 Issue 4 Pages 392-396
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Pressure responses caused by the periodic oscillation of inlet gas flow were measured in a three-dimensional fluidized bed. Showing that pressure responses could be classified into five groups in terms of both the inlet frequency and the flow rate of gas, operating conditions suitable for pulsed fluidization were defined. The model for pressure fluctuation previously reported was modified by considering the momentum of splashed particles at the top of the bed. The pressure response curves calculated from this model were found to explain well the experimental results obtained under both the externally oscillated inlet-gas flow condition and the free-bubbling condition.
    It was found that the fluidized bed was a highly resonant system and that its frequency agreed with the natural frequency of the bed estimated from a linearized model and is controllable by change of bed height and plenum volume.
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  • Seiichiro Kaguei, Dong Il Lee, Noriaki Wakao
    1980 Volume 6 Issue 4 Pages 397-403
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    With concentration of the adsorbing gaseous species assumed to possess radial symmetry in the spherical solid adsorbent particle, the dispersion coefficient of the gas flowing in the adsorbent packed bed is investigated theoretically. The result showed that the dispersion coefficient was identical with that under inert condition. Experimental measurements made with nitrogen-spherical activated carbon also verified the theory.
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  • Katsuya Ebara, Sankichi Takahashi, Kazuyuki Ito, Yoshiyuki Koike
    1980 Volume 6 Issue 4 Pages 404-409
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Studies of the application of reverse osmosis in enrichment of potato juice were conducted under practical conditions by means of a tubular-type pilot plant. The main problem was the flux decline due to membrane fouling. The flux decreased about 30% in only 5 hours operation in the absence of membrane cleaning. Sponge ball cleaning was very effective in maintaining steady performance. Diameter of the ball was a little larger than the membrane diameter and the interval for cleaning was every 30-60 minutes.
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  • Mompei Shirato, Toshiro Murase, Hidetoshi Mori, Akira Okada, Yutaka Mi ...
    1980 Volume 6 Issue 4 Pages 410-416
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    To obtain a numerical method for determining the moisture distribution in granular beds under so-called air blow drainage, the effects of air flow on deliquoring rate are represented in terms of the fictitious height of granular bed, and the previous equations for gravitational drainage are modified in view of the existence of air pressure. Equations for predicting the time change in moisture distribution through the beds under constant-pressure air blow are presented. It is shown that the moisture distribution and the average moisture content of the bed under air blow drainage can be easily evaluated in the ways similar to those for gravitational drainage. It is also illustrated that the final equilibrium moisture distribution of the bed can be well estimated from that of the bed drained by gravity.
    Satisfactory agreements between calculations and experiments are confirmed for air blow dehydration of packed beds of glass beads, Soma standard sand and calcium carbonate particles, the mean particle diameters of which range from 55μm to 360μm.
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  • Michiharu Toh, Yasuhiro Murakami
    1980 Volume 6 Issue 4 Pages 417-422
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Velocity profiles about fluid-loaded hinged and spring-loaded scraper blades were obtained by observing suspended ion exchange resin beads in syrup solution and taking photographs of their streaks. Pressure on the wall of an aginated vessel exerted by the movement of these blades was measured by a pressure transducer attached to the vessel wall.
    These experimental results agreed fairly well with the theoretical values using the stream function based on the lubrication theory concerning viscous flow between two inclined planes moving at any arbitrary relative velocity.
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  • Michiharu Toh, Yasuhiro Murakami
    1980 Volume 6 Issue 4 Pages 423-427
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    When a spring-loaded scraper blade thrusts on a vessel wall, the force exerted on the blade was considered as the sum of the drag force of the blade and the friction force between the tip of the blade and the vessel wall. The drag force was obtained by two kinds of experiment :
    (1) Loaded force was varied by the length of a coil spring, and the drag force of the blade was obtained by extrapolating the force to zero loaded force.
    (2) Clearance between the tip of the blade and the vessel wall was changed by the diameter of a roller fitted on both ends of the blade tip, and the drag force of the blade was obtained as the force at zero clearance.
    The experimental drag force was compared with the theoretical value. The experimental equation of power consumption of the blade was obtained as the sum of the power against the drag force of the blade and the power against the friction force between the tip of the blade and the vessel wall.
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  • Mitsuo Sakata, Terukatsu Miyauchi, Nobuyuki Imaishi, Takao Tsukada, Ka ...
    1980 Volume 6 Issue 4 Pages 428-439
    Published: July 10, 1980
    Released: October 21, 2009
    JOURNALS FREE ACCESS
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