KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 14 , Issue 1
Showing 1-23 articles out of 23 articles from the selected issue
  • Takayuki Watanabe, Takuya Honda, Atsushi Kanzawa
    1988 Volume 14 Issue 1 Pages 1-7
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Control of energy flow density is required when a plasma flow is used for material treatment. For this purpose, hydrodynamic, magnetic or mechanical control may be used. The object of this study is to suppress the outward radial flow of the plasma flow. Sharpness of heat flux distribution to a flat plate is required in plasma cutting. Therefore, the following two experiments were carried out.
    One was to sharpen the enthalpy flow distribution of a thermal argon plasma jet, and the other was to sharpen the heat flux distribution to the plate. These energy flow densities of the plasma flow were raised by an inward radial blowing gas. This radial blowing gas was injected through a circumferential slit around the jet nozzle exit.
    Q-value, defined as the ratio of maximum energy flow to the half-value width, is adopted as an evaluation of sharpness. Not only the Q-value of enthalpy flow of the plasma but also that of heat transfer to the plate reached maximum with the radial blowing gas flow rate.
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  • Takashi Moriyoshi, Yasuhiro Uosaki, Masahiko Kikuchi
    1988 Volume 14 Issue 1 Pages 8-13
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    To explain the effect of pressure on the liquid-liquid equilibria of two butanolwater systems, the solubility isotherms were thermodynamically analyzed by applying the Scatchard-Hamer equation to the activity coefficients of the components. The differences (Δv1 and Δv2) in the partial molar volumes of the components between the two liquid phases were evaluated in the range 0.1202.6 MPa at 302.95 and 322.75 K. The results for Δv1 and Δv2 agreed satisfactorily in sign and magnitude with those determined separately from the partial molar volumes. It is concluded that the Scatchard-Hamer equation is sufficiently applicable to the present systems and leads to reasonable results in analyzing the effect of pressure on the liquid-liquid equilibria.
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  • Kunio Atsumi, Toshio Makino, Kiyoshi Kato, Toshiro Murase, Eiji Iritan ...
    1988 Volume 14 Issue 1 Pages 14-19
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Thin-cake filtration with cylindrical dynamic filter can be achieved by applying an intensive shear to the liquid and a Taylor vortex flow in the annular space between two coaxially arranged filter cylinders. To determine the operational factors affecting the power required for a rotating inner cylinder, the frictional resistance of grooved rotors in the filter chamber without permeation or throughflow was studied. The effect of the groove and chamber dimensions on the transition to Taylor vortex flow was analysed, using a flow-visualization technique.
    The groove effect on the frictional resistance was represented by means of a newly defined factor, taking into account the number of grooves and their width. The rotating torque of the inner cylinder was evaluated in terms of the relationships among three main factors : the ratio of groove to rotor surface area, the ratio of annular gap width to inner cylinder radius, and the rotor Reynolds number. Empirical equations of the frictional coefficient as a function of the operational variables were proposed for the flow region of Taylor vortices. It is shown that the rotating power of the grooved rotor has the same value as that of the smoothed rotor provided the surface area ratio is below a critical value. The critical Reynolds number is also determined for estimating the onset of instability in laminar flow with Taylor vortex formation.
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  • Yoshinori Kutsuwa, Kouji Kojima, Hisayoshi Matsuyama
    1988 Volume 14 Issue 1 Pages 20-25
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    In the fault diagnosis of a batch process which has a few measured variables, the time-varying information (trend) of the measured variables is often used. Patternrecognition technique is useful in finding the correspondence between the trend and origins of failures occurring in the process. In the present work, a method to diagnose the fault in a batch process is developed utilizing pattern-recognition. In this method, the origin of failure is detected by matching the pattern observed in the batch process with a pattern prepared beforehand (typical pattern) for each origin. Then, the typical pattern is improved to make diagnosis more accurate. Experiments of fault diagnosis in the batch process confirm the effectiveness of the proposed method.
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  • Koichi Tabei, Masanobu Hasatani, Masao Kuroda
    1988 Volume 14 Issue 1 Pages 26-31
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The axial motion of spherical packings in a mobile bed was studied by cinematography.
    Upward and downward velocities, and absolute-value mean and root-mean-square velocities of the packings were evaluated through analysis of the axial motion of the packings. Disperision coefficients of the spherical packings were measured experimentally on the basis of the dispersion model.
    The velocities of the spherical packings and the dispersion cefficients increased with increasing gas and liquid velocities and with increasing column diameter. On the other hand, the Peclet number, Pe=DpUpz/Epz, decreased with increasing gas and liquid velocities and column diameter.
    On the assumption that the relationship between the mean particle velocity and the dispersion coefficient in the kinetic theory of gases is applicable to these phenomena, the Peclet number was expressed as a function of the particle holdup. Consequently, the correlations for each mean velocity and the dispersion coefficient were presented as a function of the holdups and the diameter ratio of the spherical packings to the column.
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  • Akio Tanishita, Masato Fukushima, Hideaki Orimo, Hisao Nishimoto, Naos ...
    1988 Volume 14 Issue 1 Pages 32-37
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Thermodynamic property is very important in selecting the working fluid for energy conversion cycles for the low-or middle-grade thermal energy source.
    In this study, the Peng-Robinson equation of state was applied to predict the property and its binary energy interaction parameters, δij, were calculated from the vapor-liquid experimental data of 15 fron binary systems. As a result of many computations, δij was regarded as almost independent of both temperature and composition.
    To correlate 1-δij with its constituents, an empirical function composed of critical volume, acentric factor and molecular weight was obtained. The RMS deviation of the calculation was smaller than 3.1%.
    The result of prediction of vapor-liquid equilibrium by the Peng-Robinson equation of state with δij, correlations was in RMS of average deviation of 7.3% in pressure and 3.4% in vapor phase composition. The correlation can be also applied to the saturated liquid volume, and an accuracy better than 5.1% was obtained for binary mixtures.
    Following those studies, the calculation technique for δij obtained here is thought to be very useful in evaluating and selecting the working fluids of fron mixture.
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  • Yoshikazu Kuga, Jiro Koga, Ichiro Inoue
    1988 Volume 14 Issue 1 Pages 38-45
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The effects of the flow rate of air and the discharge position of particles on the size of products of a screen mill were investigated experimentally by use of Soma sand of size 500 to 1000μm. The impact velocity of the mill hammers was set at 32.3, 47.1, 61.6 and 91.0 m/s. The size of products discharged from the center of the mill with air was about 10μm, which was about one-third to one-tenth the size of products discharged through the screen.
    This result could be analyzed by the theory of kinetic analysis based on the breakage probability and the distribution function of single-impact crushing. The apparent frequency of impact crushing in the mill in the former case was about 800 to 5300, which was about ten to forty times that of the latter case.
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  • Mitsuo Yamashiro, Hiroshi Kuno
    1988 Volume 14 Issue 1 Pages 46-53
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Gravity flows of powders from a hopper with an efflux tube have been experimentally studied. Rates of efflux of glass beads or spherical polystyrene particles of various sizes depend on the suction of negative pressure produced below the orifice and are expressed by
    W=CρB1/2 (P2-P1) 1/2 (D-kd1/2) 2
    where W is the efflux rate of powder, ρB is the apparent density of the powder in the hopper, P2 and P1 are pressures above and below the orifice, D is the diameter of the efflux tube, d is the particle diameter and C and k are constants.
    The rates of efflux for mixtures of various mixing ratio of two of the above powders were also expressed by the same equation using the geometrical average diameter of the mixture for d.
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  • Hiroyuki Kawasaki, Kiyotaka Kawashima, Hisaya Tanaka
    1988 Volume 14 Issue 1 Pages 54-62
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Regarding mass transfer accompanied by reaction between solid and fluid, the dissolution of metallic copper in CuCl2-HCl aqueous solution was investigated. Experiments were carried out using vertical tubes of 0.92 cm and 2.8 cm diameter and a packed column of 5.0 cm diameter packed with cylinders of 0.5 cm diameter and 0.5 cm length. The dissolution rates of copper samples were measured in air-liquid upward cocurrent flow through these apparatuses.
    The proportionality of the dissolution rate to the concentration of Cu2+ in bulk liquid suggests that the diffusion rate of Cu2+ is equimolal to the metal dissolution rate and that Cu+ is produced on the metal surface. The irreversible instantaneous reaction model was applied to the reaction between Cu+ and Cl- which occurred in the neighborhood of the surface.
    It was found that there were two regions in the dissolution rate pattern with respect to the ratio CC/CA, where CC and CA were the concentrations of Cl-and Cu2+ in bulk liquid, respectively. One is the case of CC/CA 23, where the dissolution rate is independent of CC and is directly proportional to CA. The other is the case of CC/CA<23, where the rate is proportional to CC.
    In both cases the mass transfer coefficients of Cu2+ in gas-liquid upward cocurrent flow were calculated using the relation between the metal dissolution rate and the driving force of Cu2+ transfer. In vertical tubes, the mass transfer coefficients over the whole range of CC /CA were correlated by the dimensionless relation which was applicable to the case in the absence of reaction discussed in our previous study. In a packed column, the coefficients were correlated by the same dimensionless relation in the range of CC/CA≥ 23.
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  • Masaru Nakaiwa, Masaru Owa, Takaji Akiya, Shigetake Kawasaki, Masahito ...
    1988 Volume 14 Issue 1 Pages 63-70
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    In this study, the operating pressure of a plate-to-plate heat-integrated distillation column was investigated. A condition of operating pressure was found that minimizes the pressure difference between rectifying section and stripping section, thus saving separation energy. Also, a procedure is proposed for determining this condition. The minimum value of compression work required for operating this distillation column can be calculated from this condition. Further, a benzene-toluene binary mixture was adopted as a calculation example to show the usefulness of the proposed procedure.
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  • Jusuke Hidaka, Nobuo Yonekubo, Atsuko Shimosaka, Shigeo Miwa
    1988 Volume 14 Issue 1 Pages 71-78
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The acoustic noise generated by the flowing particles on an inclined plate was studied to measure simultaneously the flow rate and particle size.
    The pressure waveform of the flow noise was estimated on the basis of the generation mechanism of the sound of impact when two particles collide.
    The frequency spectrum of the calculated pressure waveform agrees well with the measured one.
    Correlation between the flow rate and the pressure of flow noise was obtained, and the frequency of flow noise was related closely to particle diameter. Further, the mean collision time and the mean distance between flowing particles could be estimated by the frequency spectrum of the flow noise.
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  • Masanobu Hasatani, Fujio Watanabe, Chisato Marumo
    1988 Volume 14 Issue 1 Pages 79-86
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Structural molecular sieving carbons (MSC) were produced from two kinds of polyvinylformal (PVF) forms with different chemical compositions under various production conditions, and the separation characteristics of air at low temperatures (140 to 300 K) were experimentally investigated in relation to the physical properties of the structural MSC produced. Based on the breakthrough measured in a packed bed of the structural MSC, the characteristics of N2-O2 separation from air were studied from the standpoints of the separation temperature, the chemical composition of a raw PVF form and the production conditions, and the reduction in separation ability by repetition of the operation was also examined. It seemed that the structural MSC produced in this work are usable for air separation at a low temperature. The results of the adsorption equilibrium and the rate for both N2 and O2 on the fine particle of the structural MSC showed that the separation of air at a low temperature is affected by the intraparticle diffusion rate rather than the adsorption amount of each component. These points suggested that the driving force of the separation at low temperature is the diffusion rate difference between N2 and O2, similarly to the case of a pressure swing adsorption.
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  • Ikuro Shishido, Toshimitsu Muramatsu, Shigemori Ohtani
    1988 Volume 14 Issue 1 Pages 87-94
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Changes of local moisture content and stress during drying are calculated by considering both osmotic suction pressure and stress gradients as the effective driving force of moisture transfer by use of the finite-element method.
    Calculated local moisture content shows good agreement with experimental values. Relatively large tensile stress at the surface of drying stock and compressive stress in the stock are obtained under high-speed drying conditions. Calculated results show the occurrence of tensile stress in the material under certain conditions. Stress in the mixed clay seems to be smaller in value than in Kibushi clay, and from this result, possibility of avoidance of cracking may be confirmed by adding a small amount of glass beads, even under high-speed drying conditions.
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  • Akira Yasunishi, Yutaka Tada
    1988 Volume 14 Issue 1 Pages 95-102
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The volatile matter produced from sapwood of konara (Quercus serrata) by pyrolysis at 7731073 K was decomposed (catalytic cracking or secondary pyrolysis) with four kinds of synthesized Na-zeolite (Si/Al=11.4, pore diameter=0.31 nm) or inert quartz sand at the same temperature. By using the zeolites instead of quartz sand, the yield of the wood gas was increased. In particular, the yields of carbon dioxide, methane, ethane and propylene were greatly increased at 773873 K. The NaX zeolite (F-9), the pore diameter of which is about 0.9 nm, has the largest effect on the catalytic cracking of the volatile matter among the zeolites used in this work.
    When the zeolite F-9 was used at 873K repeatedly, its catalytic cracking activity was lowered and the yields and qualities of the products progressively approached those for quartz sand. The deactivated zeolite recovered almost the same degree of activity as fresh zeolite by oxy-regeneration with air. The rate of deactivation of the regenerated zeolite, however, was a little higher than that of the fresh zeolite.
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  • Eiji Obata, Hiroshi Takahashi, Makoto Akiyoshi, Koji Ando, Haruo Watan ...
    1988 Volume 14 Issue 1 Pages 103-106
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    When a fluidized bed is formed by a superficial velocity the overall height of the fluidized bed may be divided into sections of given height. A measurement of particle size distribution is developed by means of the superficial velocity and the pressure drops across fluidized beds of various heights.
    The particle mass in a section of fluidized bed and the voidage are directly calculated by the pressure drop across the bed height. The mean diameter of the particles in a fluidized bed is regarded as the equivalent volume diameter, xi, which can be calculated by the superficial velocity, uf, and the voidage function, F (εi), follows :
    uf=v∞1/F (ε1) =v∞2/F (ε2) =…=v∞i/F (εi) =…
    v∞i= (φsxi) 2p-ρ) g/18μ
    as where φs refers to the particle-shape factor. The shape factors of experimental material can be obtained by the minimum voidage for fluidization.
    The particle size distributions of crushed silica sand and crushed glass measured by this method were in good agreement with microscopic data and settling balance data.
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  • Yoshishige Hayashi, Eiji Hirai, Yasuhide Nakano, Masakatsu Urairi
    1988 Volume 14 Issue 1 Pages 107-111
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Measurements of liquid holdup and pressure drop were made for the two-phase flow of air-water through a crossflow gas-liquid contactor packed with 12-mm ceramic Raschig rings, 12-mm ceramic Berl saddles or S·O-shape polyethylene Tellerettes. For the crossflow operation, no flooding was observed ; however, the liquid was deflected to the flow direction of gas with increasing gas flow rate and eventually a violent splashing of liquid occurred. To correlate pressure drop data for the two-phase flow with the Blake-type friction factor, imaginary packings consisting of dry packings and total liquid holdup in the irrigated packed bed were supposed and the surface of packings per unit volume of imaginary dry packings, αv, was evaluated on the basis of the measured values of total liquid holdup. When the values of ReG were calculated from the evaluated values for αv, pressure drop data in the crossflow packed column could be correlated by the Blake-type friction factor regardless of the difference in geometry of the three types of packings.
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  • Kazuhisa Ohtaguchi, Taku Katahira, Ichiro Inoue
    1988 Volume 14 Issue 1 Pages 111-114
    Published: January 10, 1988
    Released: October 21, 2009
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    Attempts were made with the lactic acid bacterium Streptococcus thermophilus on lactose medium to seek out the optimal cultivation condition to increase the cell mass concentration in batch cultures. The batch processing parameters involved were initial substrate concentration, inoculum size and cellular activities of inoculated cells. Change in cellular activities was adjusted with fed-batch preculture technique by regulating the feed rate per unit culture volume and the substrate concentration in the medium. Consequently, the highest cell mass concentration of 1.4 kg/m3 was attained with an inoculum from the preculture vessel of the dilution rate at 0.35h-1 and substrate concentration in the medium at 77 kg/m 3.
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  • Masataka Shimizu, Kentaro Nobori, So Takeoka
    1988 Volume 14 Issue 1 Pages 114-117
    Published: January 10, 1988
    Released: October 21, 2009
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    An attempt was made to produce an inner fin-type tubular reactor for methanol decomposition. Raney nickel alloy catalyst was attached to the surface of the inner wall and fin. The reaction and heat transfer performance of this type of reactor were compared with those of the packed-bed reactor. The reaction performance of the reactors was found to be controlled. by the heat transfer rate. The overall heat transfer coefficient for the inner fin-type reactor was about 20 times larger than that for the packed-bed reactor. It was suggested that the former reactor is effective for on-board reforming, which requires excellent dynamic characteristics and compact reactor size.
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  • Mamoru Ishida, Masayuki Horio
    1988 Volume 14 Issue 1 Pages 117-120
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    To establish a relationship between the bubble flow distribution and the radial distribution of large floating bodies in a fluidized bed, the behavior of float tracer (polypropylene tablet, 8 mm φ × 4 mm thick) in fluidized beds (0.3 m in diameter, and 0.12 and 0.24 m in height) were observed. by a video camera from the top of the bed. The validity of the video method was confirmed by direct measurement of the tracer concentration based on solid sampling. A clear proportionality was found between the excess gas velocity distribution and the absence index of float tracers.
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  • Ikuho Yamada, Setsuro Hiraoka, Tsutomu Aragaki, Yoshihito Kato
    1988 Volume 14 Issue 1 Pages 120-122
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    A numerical method is proposed for solving the steady one-dimensional diffusion problem described by Pe-1 yy′-f (y) =0 under the boundary conditions given by Danckwerts, y′=Pe (y-yF) at x=0 and y′= 0 at x=1. In this method the central finite difference equation is used for calculating yj and yj (0≤ jN-1), where j=0 and j=N denote x=0 and x=1, respectively. However, the feature of this method is to use the following finite difference equation, which gives the relationship between y N-1 and yN.
    yN-1-yN-Peh2/2Peh+4 {f (y N-1) +f (yN)} =0
    This equation is derived by using yN-1 = (ΔyN-1 + ∇yN) /2 and yN-1 = (ΔyN-1 + yN) /2 with the boundary condition yN=0 where the symbols Δ and show the forward and backward difference operators. The proposed method provides a stable solution at large Pe number as illustrated in numerical examples.
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  • Toshiro Murase, Hideo Nakakura, Hidetoshi Mori, Tadashi Ogura, Mompei ...
    1988 Volume 14 Issue 1 Pages 123-126
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    A method is presented for calculating the drained liquid volume in gravitational drainage by applying an empirical correction, which takes into account the effects of liquid viscosity on film flow, to the author's prior equations for the dewatering of granular beds. It was shown that the dehydration rate of highly viscous Newtonian liquid is strongly affected by the existence of filmwise liquid flow when the modified capillary number is larger than 2.5.
    The predicted results agreed well with the experimental results for packed beds of glass beads and calcium carbonate particles of diameter 1641875 μm, under conditions where the liquid viscosity ranges from 0.001 to 0.76 Pa · s.
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  • Yoshiyuki Bando, Michio Kuraishi, Makoto Nishimura, Kazumi Horii, Koji ...
    1988 Volume 14 Issue 1 Pages 126-130
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Gas entrainment by liquid flowing downward into a downcomer was considered to be applicable as a method of gas transport. By using downcomer s of different diameter and length, the gas entrainment was experimentally examined.
    The flow pattern in the downcomer changed with increasing liquid flow rate : annular flow, slug flow, and mixed flow. The ratio of gas/liquid flow rates showed the maximum during liquid flow rate in the slug flow regime. Under the present experimental conditions, the maximum ratio of gas/ liquid flow rates increased with decreasing downcomer diameter.
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  • Masao Imaeda, Si Chi Ma, Kyoji Hashimoto
    1988 Volume 14 Issue 1 Pages 130-133
    Published: January 10, 1988
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    When a large chage is introduced in a reference value, saturation in a manipulated variable results. This would often happen for the control system which has rapid response. That gives undesirable effects and the response becomes rather oscillatory. In this case a softening filter works effectively. A first-order softening filter for the digital PID control system is discussed in this paper. A simple desing method for the filter is considered. The proposed method may be considered as a practical and effective one to improve control performance.
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