Chemical engineering
Print ISSN : 0375-9253
Volume 17, Issue 7
Displaying 1-7 of 7 articles from this issue
  • General Consideration
    Y. Oyama, K. Endou
    1953 Volume 17 Issue 7 Pages 256-260
    Published: July 01, 1953
    Released on J-STAGE: July 09, 2009
    JOURNAL FREE ACCESS
    Some physical interpretation is made in connection with the basic consideration of the flow of liquid on the rotating disk, in order to make clear the method of application of formula given for the determination of maxium drop-size.
    To investigate the mechanism of atomization, especially in the determination of the type of dropsize distribution, some assumption is introduced from the view point of surface energy increase in breaking up of the droplet. The result obtained is the type of Pearso's No. 5 distribution. Thus we find we can explain the physical aspect of the type of distribution presented by Tanasawa.
    Next the general trend of the method of calculation has been studied in order to determine the trajectory of droplets, Substituting the molecular viscosity of surrounding air for the turbulent viscosity affected by the mutual effect of Karman's voltex, we introduced a basic assumption for the mutual effect of falling droplets. From this inference, we see, the first approach can be made in accordance with the data presented by Marshall and in our own experimental work.
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  • The Generalized Correlation of Loading Velocities
    T. Otaka, M. Kimura
    1953 Volume 17 Issue 7 Pages 261-268
    Published: July 01, 1953
    Released on J-STAGE: March 08, 2010
    JOURNAL FREE ACCESS
    Although the loading velocity is generally used in industry as the limiting criterion for tower operation, considerably few correlations as are available for flooding velocities have been proposed on loading conditions.
    In this paper, the results obtained by previous investigators concerning loading velocity in packed towers are analyzed and the generalized correlation of loading velocities based on those data is presented.
    The results are shown in Fig. 6, as a dimensionless plot, where the ordinate is (ug2/2gd)(dL/μl)-0.15(4.8/a·d)2.50, and the abscissa is the ratio of superficial gas velocity to liquid, (ug/ul).
    The advantage of the form presented here over the usual Sherwood correlation of flooding velocities is that the correction of liquid viscosity effect is made by the dimensionless group, (dL/μl)-0.15 and Lobo's packing constant which considerably varies with packing procedure is not included. The proposed correlation enables one to predict, without any experimental work, the loading velocity of any liquid for most of the common types of packings.
    Nomenclature:
    d: nominal diameter of packing
    g: accelaration due to gravity
    L mass velocity of liquid
    ug: superficial gas velocity
    ul: superficial liquid velocity
    μl: viscosity of liquid
    (a·d): Fujita's characteristic constant of packing.
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  • Y. Oyama, M. Eguti, K. Endou
    1953 Volume 17 Issue 7 Pages 269-275
    Published: July 01, 1953
    Released on J-STAGE: July 09, 2009
    JOURNAL FREE ACCESS
    The experimental studies reported in this paper were undertaken to investigate the relationship between drop-size distribution and the principal factors operating a centrifugal disk atomizer. Discs used are of diameter from 6cm to 14cm., and are rotated at the rate of less than 9000 rev./min.
    Results obtained are summarized as follows:
    (1) The average drop-size on the surface are given in our experiments:
    (2) The maximam drop-sizes are expressed experimentally:
    (3) In most of our experiments the distribution of droplets were remarkably affected by the rate of rotation. With the increase of spinning speed, the distribution types tended to give single modal, while when discs were operated at the rate of less than 6000rev/min., distribution types were found to be multi-modal. Log-Probability distribution mostly proved satisfactory in single modal types, as shown in the resultant data.
    In the above equation:
    a: Average drop-size based on the surface cm.
    d: Maximum drop-size cm.
    D: Diameter of disk cm.
    N: Rate of rotation rev./min.
    q: Feed rate of water c.c./sec.
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  • VIII Experiments on the cases of various packings
    S. Maeda, K. Kawazoe
    1953 Volume 17 Issue 7 Pages 276-283
    Published: July 01, 1953
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    Theoretical equations of heat transfer between the gas flowing through granular solids and the cylindrical wall, has already been studied and checked by experiments, using cylindrical catalysts both. with and without chemical reaction. (Rep. I-VII) The present paper deals with the experiments on various types of packings.
    Hot air (ca. 200°C) was passed through a cylindrical packed tower whose wall was kept at constant temp. by boiling water, and the axial temp. distribution within the layer as well as the average temps. of the gas at the inlet and the outlet were measured. The turbulent conductivity (effective cond.) λ, the film coeft. based upon the true film temp. of the wall h' and that based upon the average temp. h were calculated. The experimental ranges were as follows (length in mm):
    From, these the following results were obtained.
    1) In regard to these packings, the observed temps. of the average tm and the center tc at the exit of the packed layer varied appreciably according to some incidental changes of the packed condition, and λ/k, 1/b, and hD/k, could not be satisfactorily correlated by any nondimensional formula but what are given in Table 8·2 and eq. (48) (length in [m]). 2) Assuming D is constant, λ/k and hD/k have the maximum value for an optimum value of dk/D. These values of dk/D are 0.227-0.325 for λ/k and 0.13-0.273 for hD/k. 3) dk/D, the wall effect, has an effect upon hD/k, 1/b and also upon λ/k (which was not effected in the case of cylindrical packing).
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  • [in Japanese]
    1953 Volume 17 Issue 7 Pages 284-286
    Published: July 01, 1953
    Released on J-STAGE: July 09, 2009
    JOURNAL FREE ACCESS
  • [in Japanese]
    1953 Volume 17 Issue 7 Pages 287-289
    Published: July 01, 1953
    Released on J-STAGE: July 09, 2009
    JOURNAL FREE ACCESS
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  • [in Japanese]
    1953 Volume 17 Issue 7 Pages 292
    Published: July 01, 1953
    Released on J-STAGE: July 09, 2009
    JOURNAL FREE ACCESS
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