Chemical engineering
Print ISSN : 0375-9253
Volume 37, Issue 12
Displaying 1-7 of 7 articles from this issue
  • Shinzo Ohkado
    1973 Volume 37 Issue 12 Pages 1205-1211,a3
    Published: December 05, 1973
    Released on J-STAGE: October 07, 2010
    JOURNAL FREE ACCESS
    Theoretical melting rate V is obtained using many approximations. For a flat wall, the relation between non-dimensional melting rate Vγ=0 and non-dimensional pressure P/μc is
    where N is a coefficient concerned with temperature dependence of viscosity. For a fin-type wall, correction factor V/Vγ=0 is obtained.
    Regarding melt spinning of plastics, 1) pressure and viscosity have little effect, 2) wall temperature has a large effect, 3) interval of outlet grooves and index of temperature dependence of viscosity have medium effect, 4) wall speed moving across the direction of pressure has no effect, 5) thickness of molten plastics film is about 0.1 mm, and nearly constant in several types of melters, 6) optimal fin shape can be decided for a pair of V and heat conductivity of wall metal, 7) for example, “I. C. I.-type pressure melter” with aluminum wall, optimal shape is nearly an isosceles triangle of height double the base, and even then V is only 1.6 times Vγ=0.
    Download PDF (2187K)
  • Equations of rate of condensation over a wide range of vapor concentration
    Tsuyoshi Munakata, Nobuyuki Hirai, Katsuo Yokoyama
    1973 Volume 37 Issue 12 Pages 1212-1217,a3
    Published: December 05, 1973
    Released on J-STAGE: October 07, 2010
    JOURNAL FREE ACCESS
    Rate of condensation of vapor from vapor-gas mixture flowing in a tube under reduced pressure was analysed numerically and measured experimentally. Under the condition of laminar flow of gas phase, two equations for the rate of condensation are proposed. One of them, to be applied when vapor concentration is high, is formulated from the result of numerical calculation performed with the aid of Baasel's simplification of the basic transport equations. For low concentration of vapor, another equation is derived by applying Hausen's equation of the average heat transfer coefficient to mass transfer. Experimental results obtained for the three systems C2H5OH-air, n-C3H7OH-air and n-C4H9OH-air over a wide range of vapor concentration are in good agreement with these two equations.
    Download PDF (1916K)
  • Saburo Yashima, Yoshiteru Kanda, Toru Sasaki, Masayoshi Iijima, Fumio ...
    1973 Volume 37 Issue 12 Pages 1218-1226,a3
    Published: December 05, 1973
    Released on J-STAGE: October 07, 2010
    JOURNAL FREE ACCESS
    Two kinds of glassy samples and six kinds of rock samples were used in measuring of mechanical properties. From compression tests, the following results were obtained. 1) The compressive strength and Young's modulus of all kinds of cylindrical specimens increase with increasing strain rate, while Poission's ratio decreases with increasing strain rate.
    From compression tests of spherical specimens under dynamic loading rate the following results were obtained. 2) The sphere compressive strength and new surface produced increases with increasing loading rate, but the fracture surface energy has a tendency to decrease with increasing loading rate. Their values were on the order of 104ergs/cm2. 3) T he size distribution of fractured products of spherical specimens was represented by the Gaudin-Meloy-Harris size distribution equation.
    Download PDF (2651K)
  • Nobutoshi Tanaka, Kazutaka Makino, Koichi Iinoya
    1973 Volume 37 Issue 12 Pages 1226-1234,a3
    Published: December 05, 1973
    Released on J-STAGE: October 07, 2010
    JOURNAL FREE ACCESS
    The annual cost of an air filter is formulated in terms of the fixed and power costs of a fan, the fixed cost of an air filter, and the renewal cost of a filter medium. For an automatic renewal-type air filter, in particular, the cost of a medium is estimated considering the merit of a partial renewal operation. For several typical media, the optimal filtering velocity and the operating pressure drop (final value in a panel-type, and average value in an automatic renewal-type) are then calculated for various of flow rate and dust concentration. The values of various coefficients for computations were practically decided by inquiring of several makers and users, Approximate optimal solutions are analytically derived and the sensitivity of various parameters on the optimal solutions is discussed.
    For example, it is concluded that the optimal conditions are remarkably affected by dust concentration, or the pressure drop characteristics of a medium, but hardly at all by flow rate. In an automatic-renewal type, it is shown that 20% cost reduction at most is obtained by a partial renewal operation.
    Download PDF (2439K)
  • Tadashi Shirotsuka, Hideo Arakawa
    1973 Volume 37 Issue 12 Pages 1234-1241,a3
    Published: December 05, 1973
    Released on J-STAGE: October 07, 2010
    JOURNAL FREE ACCESS
    This report discusses how to estimate the time constant of a gas absorption plate column for gas and liquid flow change.
    The time constant of the N-th plate is approximately calculated as NT+T3 in the case of m<1 or large mass-transfer rate compared to liquid rate, where m is the slope of gas-liquid equilibrium, T is hydraulic time constant and T3 is mass transfer time constant per unit plate.
    The estimated time constants agree within ±20% accuracy with experimental responses of five plates in a gas absorption column.
    Download PDF (2158K)
  • Takeo Yano, Toshiro Aratani, Noboru Kinoshita, Naoyoshi Kawakami
    1973 Volume 37 Issue 12 Pages 1241-1247,a3
    Published: December 05, 1973
    Released on J-STAGE: October 07, 2010
    JOURNAL FREE ACCESS
    An extraction tower for which liquids were fed alternately in square wave form was dynamically simulated by simplified mathematical models. The assumptions employed for the simplifications were discussed by comparing experimental responses with computed responses of the models. Fixing flow rates, step response curves were recorded for relatively high concentration inputs at various initial concentrations of both light and heavy phases. Ternary system used in this experiment was Toluene-acetic acid-water system, the distribution coefficient of which heavily depended on the equilibrium concentration. A model assuming pseudo-steady state for dispersed phase was ensured to be sufficient for the dynamic simulation of the tower, when the mean residence time (Holdup/Volume flow rate) of continuous phase was 20 times greater than that of dispersed phase. This made it possible to treat the tower as a series of concentrated constant system. The assumption of averaging the square wave flow rates was also sure to hold in our experimental conditions. A nonlinear model having an adjustable over-all mass transfer capacity coefficient, which was assumed to be function of distribution coefficient, was able to describe the tower dynamics within detectable errors, even, though the distribution equilibrium showed high nonlinearity.
    Download PDF (2098K)
  • 1973 Volume 37 Issue 12 Pages 1247-1257,a1
    Published: December 05, 1973
    Released on J-STAGE: October 07, 2010
    JOURNAL FREE ACCESS
    Download PDF (1973K)
feedback
Top