Yoshiro Inoue

Osaka University, Suika, Ōsaka, Japan

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Publications (36)27.69 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Mixing time and pattern in the impeller-agitated vessel with two-bladed paddle were investigated at various mixing Reynolds numbers by use of two chemical reactions: ordinary decolorizing experiment with iodine and sodium thiosulfate and Beloousov–Zhabotinskii (BZ) periodical reaction experiment. The periodical steady color-variation in BZ reaction system remained after the sufficient time required for the complete decolorization (that is, ordinary mixing time). The sequential spatial color-patterns obtained in steady periodical variation process were similar to the transitional color patterns observed in the decolorization process. The color-patterns obtained in BZ periodical reaction were consistent with the outline of partially mixed regions where the exchange of substance is relatively slow in the vessel and they depended on mixing Reynolds number. The phase of periodical concentration oscillation in each partially mixed region was shifted with one another in spite of the same period of oscillation. Whether the period and/or phase synchronize or not in each partially mixed region would depend on the relative speed between the exchange of substance and the synchronization of periodical oscillation of concentration there. The periodical reaction could become an available tool for the visualization of distribution of those partially mixed regions containing well and bad mixing regions in impeller-agitated vessel.
    Chemical Engineering Science 10/2012; 80:30–38. DOI:10.1016/j.ces.2012.05.053 · 2.61 Impact Factor
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    ABSTRACT: The authors reviewed the correlations of power consumption in unbaffled and baffled agitated vessels with several kinds of impellers, which were developed in a wide range of Reynolds numbers from laminar to turbulent flow regions. The power correlations were based on Kamei and Hiraoka's expressions for paddle and pitched paddle impellers. The calculated correlation values agreed well with experimental ones, and the correlations will be developed the other types of impellers.
    International Journal of Chemical Engineering 01/2012; 2012. DOI:10.1155/2012/106496
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    ABSTRACT: The slurries-containing tetra-n-butyl ammonium bromide (TBAB) solution and its semiclathrate hydrate have attracted a lot of interest as latent heat transport media. These hydrate slurries contain some microparticles of crystal, and the size and shape of these hydrate particles could affect the mobility of slurries. Hence, it is essential to investigate the efficient hydrate-slurry preparation methods and the effect of hydrate particles on the fluid property of slurries for the application to latent heat transport media. In the present study, the effect of agitation on particle size distribution and aggregation of particles was studied to prepare easily flowing TBAB hydrate slurries that were suitable for fluid transport. First of all, the effects of impeller rotational speed and impeller type on the particle size and frequency of aggregation were investigated. The results suggested that the particle size distribution and the frequency of particle aggregation are strongly affected by the intensity of shear rate and its uniformity, which was controllable with impeller type and its rotation speed.
    International Journal of Chemical Engineering 01/2012; 2012. DOI:10.1155/2012/856120
  • Journal of chemical engineering of Japan 01/2012; 45(6):444-451. DOI:10.1252/jcej.11we227 · 0.61 Impact Factor
  • KAGAKU KOGAKU RONBUNSHU 01/2012; 38(4):191-202. DOI:10.1252/kakoronbunshu.38.191 · 0.39 Impact Factor
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    ABSTRACT: Enhancement mechanism of mixing with baffle in agitated vessel using rotated two-bladed paddle impeller was investigated under a laminar condition. In mixing pattern, the toroidal isolated mixing region in the baffled vessel becomes distortive and much smaller than that of unbaffled vessel. From the visualization of streak cross-sections in the baffled vessel, interestingly, the renewed streak folds (streak lobes) are generated at the vicinity of baffles in both the vertical and horizontal cross-sections. These behaviors of streak are unlike the unbaffled case that the streak stretches straightforwardly. The streak lobe is known as the mixing template that its number and size are key factor for laminar mixing in agitated vessel. The results suggest that baffles can effectively transform the circumferential flow to vertical and/or radial flows. Consequently, in the baffled vessels, not only the vicinity of vessel wall but also the tip of baffles can become the origination of streak lobe formation, and folds of streak in the vertical and circumferential directions are further enhanced with baffles.
    Chemical Engineering Science 10/2011; 66(20):4690-4701. DOI:10.1016/j.ces.2011.06.032 · 2.61 Impact Factor
  • Kagaku kōgaku ronbunshū 01/2011; 37(6):490-495. DOI:10.1252/kakoronbunshu.37.490
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    ABSTRACT: The three-phase equilibrium (pressure−temperature) relation of the difluoromethane + water binary system containing gas hydrates was measured in the pressure range from (0.20 to about 11.0) MPa and temperature range from (275.15 to 300.15) K. On the basis of each three-phase equilibrium curve, the quadruple point which consists of gaseous and liquid difluoromethane, water, and hydrate was determined as 1.45 MPa and 293.16 K. The in situ Raman spectroscopy under the three-phase (gas, water, and hydrate) equilibrium conditions showed that the crystal structure of difluoromethane gas hydrate was structure-I, where both small and large cages were occupied by the difluoromethane molecule. The overall hydration enthalpy of simple structure-I difluoromethane gas hydrate under the three-phase equilibrium conditions was evaluated by means of the Clapeyron equation.
    Journal of Chemical & Engineering Data 08/2010; 55(8):2764-2768. DOI:10.1021/je9009859 · 2.05 Impact Factor
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    ABSTRACT: The three-phase equilibrium (pressure−temperature) relations were measured for the hydrofluorocarbon (HFC) (1,1,1,2-tetrafluoroethane (-134a), pentafluoroethane (-125), or 1,1,1-trifluoroethane (-143a)) + water binary systems containing gas hydrate. The measurements were performed in the pressure range up to 10.0 MPa and the temperature range of (273.15 to 295.15) K. The invariant quadruple points (gaseous HFC, liquid HFC, aqueous, and hydrate phases) were located at 283.19 K and 0.416 MPa (HFC-134a), 283.95 K and 0.930 MPa (HFC-125), and 283.33 K and 0.838 MPa (HFC-143a), respectively. The enthalpies of hydrate dissociation to gaseous HFC and water were calculated with the Clapeyron equation, and the value was about 140 kJ·mol−1 for all HFC hydrate systems.
    Journal of Chemical & Engineering Data 08/2010; DOI:10.1021/je100528u · 2.05 Impact Factor
  • KAGAKU KOGAKU RONBUNSHU 01/2010; 36(1):57-63. DOI:10.1252/kakoronbunshu.36.57 · 0.39 Impact Factor
  • KAGAKU KOGAKU RONBUNSHU 01/2010; 36(1):1-16. DOI:10.1252/kakoronbunshu.36.1 · 0.39 Impact Factor
  • Yoshiro Inoue, Shunsuke Hashimoto
    KAGAKU KOGAKU RONBUNSHU 01/2010; 36(4):355-365. DOI:10.1252/kakoronbunshu.36.355 · 0.39 Impact Factor
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    ABSTRACT: Isolated mixing region in agitated vessel with rotated two-bladed paddle impeller and no baffle was visualized experimentally and its structural property was investigated in detail. A set of thin filaments spirally wrapping around the core of the toroidal isolated mixing region is observed under low Reynolds number conditions, which is smaller than 60. Three-dimensional geometrical structure of filament in isolated mixing region depends on the periodical perturbations caused by the rotating impeller. We have succeeded in the determination of three-dimensional geometrical structure of filament in isolated mixing region based on relation between the movement of fluid particle and filament numbers and/or wire turns. Interestingly, the wire turns of filaments are opposite to movements of fluid particles.
    Chemical Engineering Science 12/2009; 64(24):5173-5181. DOI:10.1016/j.ces.2009.08.024 · 2.61 Impact Factor
  • Source
    Yushi Hirata, Takahiro Dote, Yoshiro Inoue
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    ABSTRACT: Measurements of power and mixing time were conducted in particle suspensions by using a mixing system with a disk impeller reciprocated up and down in a cylindrical vessel. In a dilute suspension of particle volume fraction, φ, less than 0.2, the power number was almost the same as that in mixing homogeneous liquids but the time required for fluid mixing was decreased with increasing φ. In the suspension of φ equal to 0.01, the mixing time was well correlated with the gravitational settling velocity of the suspended particles. In a dense suspension of φ larger than 0.3, the power number increased appreciably and longer time was required for fluid mixing. From the variations of mixing time with the power input per suspension volume, it has been confirmed that the energy required for fluid mixing in a dilute suspension of φ less than 0.2 is smaller than that for mixing without particles. This suggests that the gravitational potential energy can be utilized for enhancing fluid mixing by the particle motion relative to the fluid motion.
    Chemical Engineering Research and Design 05/2009; 87(4):14-17. DOI:10.1016/j.cherd.2008.12.022 · 2.28 Impact Factor
  • KAGAKU KOGAKU RONBUNSHU 01/2009; 35(2):201-210. DOI:10.1252/kakoronbunshu.35.201 · 0.39 Impact Factor
  • KAGAKU KOGAKU RONBUNSHU 01/2009; 35(3):265-273. DOI:10.1252/kakoronbunshu.35.265 · 0.39 Impact Factor
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    ABSTRACT: A new type of demountable plate static mixer composed of σ-shaped elements was developed, which was designed to perform multi-lamination of two fluids through systematic splitting and inverse recombination. Its flow and mixing characteristics have been investigated by conducting the decolourisation reaction of iodine with sodium thiosulfate and CFD analysis. Visualized mixing patterns demonstrate that splitting and inverse recombination progress as designed in the flow of Re less than 10, where the number of mixing elements required for complete mixing increases with Re. At Re>10, secondary flows are generated due to the two- and three-dimensionally curved portion in the mixer, distorting the systematic splitting and recombination. They contribute to accelerating mixing progress through the deformation and elongation of the interfaces between the fluids to be mixed. The number of elements for complete mixing becomes maximum at Re of 10–20 and then decreases with further increasing Re. Mixing progress in the flow direction and cross-sectional mixing patterns obtained by CFD analysis show that splitting and inverse recombination do not perform satisfactorily in a shallow channel, which suggests that the aspect ratio of the mixer channel should be set around one if heat transfer is simultaneously taken into account. Based on the CFD velocity data, fluid particles disposed on the inlet cross-section at a time were traced in the mixer with the aspect ratio of one. Distributions of travelling or residence time of fluid particles reveal that the overall flow behaviour in the mixer approaches the plug flow with increasing Re as well as the number of mixing elements. The friction factor, which was obtained by applying the calculated pressure loss to the Fanning's equation, varies in inverse proportion to Re at Re
    Chemical Engineering Research and Design 12/2008; 86(12):1447-1453. DOI:10.1016/j.cherd.2008.09.004 · 2.28 Impact Factor
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    ABSTRACT: Thermodynamic stability and hydrogen occupancy on the hydrogen+tetra-n-butyl ammonium fluoride semi-clathrate hydrate have been investigated by means of phase equilibrium (pressure–temperature) measurements and Raman spectroscopic analyses for two mole fractions, 0.018 and 0.034 (stoichiometric for the cubic structure) of tetra-n-butyl ammonium fluoride aqueous solutions. In the case of higher concentration (0.034), the stability boundary curve of hydrogen+tetra-n-butyl ammonium fluoride semi-clathrate hydrate locates at about 23 K higher temperature than that of hydrogen+tetrahydrofuran mixed gas hydrate. The storage capacity of hydrogen in the cubic structure for the hydrogen+tetra-n-butyl ammonium fluoride semi-clathrate hydrate is smaller than that of hydrogen+tetrahydrofuran mixed gas hydrate. In the case of hydrate prepared from the lower concentration (0.018) of aqueous solution, the Raman spectra and phase behavior reveal that the cubic structure of semi-clathrate hydrate is changed to a different one at about 9 MPa and 299.2 K. The new structure can entrap larger amount of hydrogen than the cubic one. The stability boundary curve of hydrogen+tetra-n-butyl ammonium fluoride semi-clathrate hydrate obtained in the aqueous solution of lower mole fraction (0.018) is shifted to slightly low-temperature or high-pressure side from that of higher mole fraction (0.034).
    Chemical Engineering Science 12/2008; 63(24-63):5789-5794. DOI:10.1016/j.ces.2008.08.026 · 2.61 Impact Factor
  • Takako Shiba, Yoshiro Inoue
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    ABSTRACT: Mixedness and mixing ability are two kinds of quantitative indexes to evaluate fluid mixing, Mixedness is an index of spatial distribution uniformity of particular species in fluid. On the other hand, mixing ability is an index of kinematic intensity of mixing fluid motion. In this study, the new quantitative index to express kinematic mixing ability is proposed based on an information measure corresponding to a relative entropy, known as Kullback-Leibler information. The regions essentially dominating the fluid mixing motion strongly depend oil the geometric structure of Birkhoff pattern on a Poincare section, In this pattern, there are a chaotic sea and many islands enclosed by KAM curves. The new mixing ability proposed in this paper accurately expresses the potential mixing ability intrinsic to the flow field. In other word, this index coincides with the potential mixing ability predicted from Birkhoff pattern. Furthermore, there is an advantage that this index hardly depends oil the number of virtual test particles used in this calculating procedure.
    KAGAKU KOGAKU RONBUNSHU 05/2008; 34(3):313-320. DOI:10.1252/kakoronbunshu.34.313 · 0.39 Impact Factor
  • Hideki Hagihara, Yushi Hirata, Yoshiro Inoue
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    ABSTRACT: Appropriate patterning of pH distribution to obtain high conversion and selectivity of the main product was analyzed for series-parallel reactions whose reaction rates strongly depend on hydrogen ion concentration, under laminar flow in microchannels. When pH distribution in the inlet solution is adjusted so as to enhance the main reaction and suppress side reactions, the selectivity increases but conversion decreases. However, by increasing the number of inlet channels, it is possible to raise both conversion and selectivity. In addition, the conditions for obtaining high selectivity by collecting only the partial stream containing a high concentration of the main product at the Outlet of a microchannel were analyzed.
    KAGAKU KOGAKU RONBUNSHU 01/2008; 34(1):57-63. DOI:10.1252/kakoronbunshu.34.57 · 0.39 Impact Factor