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Volume 11, Issue 1
Displaying 1-16 of 16 articles from this issue
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APPLICATION TO ABSORPTION ENHANCEMENT FACTOR AND CATALYST EFFECTIVENESS FACTORTSUTOMU HIROSE1978 Volume 11 Issue 1 Pages 1-6
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSTo correlate a large number of computational results into a compact analytical equation, an improved method is proposed for technical problems which have the two asymptotes y(0)→1 and y(∞)→x. When an analytical solution g(x) for a simple system is obtained, solutions of a family of similar problems can be approximated by the equation
y=G(xj))1/j (A)
in which a parameter j is determined so that Eq. (A) agrees with the exact value at x=1, thus
j=logg(1))/logy(1)
A recently proposed method of Churchill, Usagi and Ozoe is a special case of Eq. (A) with g(x)= 1+x.
The validity of the proposed method is confirmed in an application to simultaneous diffusion-reaction problems for various systems. It is interpreted that Eq. (A) describes a family of figures "similarly transformed" from an original g(x) with a similitude ratio 1/j on a logarithmic scale.
A method of rough but simple estimation of j is also discussed.View full abstractDownload PDF (446K) -
TOHRU NIIDA, TETSUO YOSHIDA1978 Volume 11 Issue 1 Pages 7-12
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSSome features of the viscous flow pattern in an annular sector with clearance are derived from Couette-Poiseuille flow.
The resultant equations can predict such important characteristics as the location of the center, the circulation flow rate of the vortex flow and so on as functions of the net flow rate through the clearance.
The predicted features of the viscous flow pattern are confirmed by the experimental results presented by Trommelen and Beek.View full abstractDownload PDF (453K) -
HAJIME UNNO, ICHIRO INOUE1978 Volume 11 Issue 1 Pages 13-18
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSThe features of oil slick development were studied both theoretically and experimentally. The effect of the initial conditions of the oil and the oil-water interface were taken into consideration. The characteristics of oil film, such as the spreading velocity and the distribution of film thickness, are explained by theoretical solutions.View full abstractDownload PDF (412K) -
MASAMOTO NAKAJIMA, KEISUKE FUKUI, HIROMASA UEDA, TOKURO MIZUSHINA1978 Volume 11 Issue 1 Pages 19-24
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSA theoretical study is presented on the transfer problem subject to developing flow of mixed convection between vertical parallel plates. Present analysis aims to make clear the transfer mechanism for aiding and opposing flow, based upon and developing Leveque''s solution.
Average mass transfer measurements were obtained for both aiding and opposing flow in a vertical annulus by using the electrochemical method, i.e. the reduction of ferricyanide at the cathode in a solution of K4Fe(CN)6-K3Fe(CN)6-NaOH.
Both theoretical and experimental results show that the parameter Grh/Reh is able to express the effect of the buoyancy force in aiding and opposing flows. With increasing Grh/Reh in the case of aiding flow, Nusselt numbers increase, being proportional to (RehPrDh/L)n, and the exponent n decreases. As to opposing flow, the buoyancy effect is more remarkable than in the case of aiding flow. It reduces the velocity in the thermal-boundary layer and promotes rapid transition to turbulent state owing to flow instability.View full abstractDownload PDF (416K) -
HIROSHI KOMIYAMA, HAKUAI INOUE1978 Volume 11 Issue 1 Pages 25-32
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSDepletion of nitrous acid from its aqueous solution is studied over a wide range of experimental conditions. The rate and stoichiometry of this process are determined as a function of mass transfer characteristics of gas-liquid contacting devices. It is found that the depletion of nitrous acid is brought about by three different mechanisms: 1) simultaneous hydration of N2O4 and evolution of NO, both existing in equilibrium with HNO2, 2) desorption of nitrous acid molecules and 3) decomposition of HNO2 into NO and NO2 occurring in the vicinity of the liquid surface. A quantitative analysis is made using the various rate and equilibrium constants with the oxides of nitrogen. The relative importance of the three mechanisms and, hence, the rate and stoichiometry of the whole process vary with the mass transfer characteristics of the gas-liquid contactors. The rate constants of the hydration of N2O4 and of the decomposition of nitrous acid (2HNO2→NO+NO2+H2O) as well as the solubility of N2O4 were established.View full abstractDownload PDF (635K) -
SUSUMU FUKUSHIMA, KATSUHIKO KUSAKA, SADAMITSU ISHII1978 Volume 11 Issue 1 Pages 33-39
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSInterfacial areas and liquid-phase volumetric mass-transfer coefficients were measured from chemical absorption of oxygen into sulfite solution and from physical absorption of carbon dioxide into water, respectively, in the cases of one, two, three and seven strings of touching spheres, and in irrigated columns packed with spheres, Raschig rings and Berl saddles. The columns having seven strings of touching spheres used both open and closed configurations of spheres.
When the number of spheres per string is larger than 10 and the number of strings m is 3 and 7, the empirical equation of interfacial area at for sphere diameter dp is given in terms of liquid Reynolds number Ret(=4ρQl/mπdpμl) and the number of contact points of spheres per sphere q as follows:
atdp=4.8q-1.1Ret(0.27q0.25)t
The equation obtained by replacing at by ap/(1-ε) and Ret by Rep in the above equation is applicable to illustrate the data in irrigated columns packed with spheres, (1-ε) in solid fraction, with an accuracy of ±20%. Suppose q=4.2 for Raschig rings and q=2.8 for Berl saddles, the predicted values agree with the experimental data.
The Sherwood numbers are presented by the same relation for the cases of one, two, three and seven strings, where the number of touching spheres is larger than 10, as follows:
Sht=k*ltdp/DA=7.1Re1/3tSc1/2
The equation obtained by substituting k*lt by k*lp, 7.1 by 27φ(1-ε) and Ret by Rep represents the data for columns with a packing of surface shape factor φ.View full abstractDownload PDF (517K) -
HAKUAI INOUE1978 Volume 11 Issue 1 Pages 40-44
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSBy the analysis of an autothermal reactor using a one-dimensional simple model, it was found that the maximum temperature in the reactor is uniquely defined by the parameters a and ft. The static stability criteria for operation without reactor run-away were derived theoretically for n-th order irreversible and reversible reactions.View full abstractDownload PDF (372K) -
KOHEI OGAWA, SHIRO ITO, HIDEHARU KISHINO1978 Volume 11 Issue 1 Pages 44-47
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSBy using the entropy of information theory, a more reasonable separation efficiency can be defined from the point of view of statistics. This newly defined separation efficiency varies from zero for the case of non-separation, in which the mass fractions of valuable component in both product and residuum take the same values as that in feed, to unity for the case of ideal separation, in which the valuable material and useless material in the feed leave the separator as the product and the residuum, respectively, and has sufficient detection sensitivity for even a small change of mass fraction of components in the product or in the residuum. The newly defined separation efficiency, which satisfies the fundamental requirements described above and has clear physical meaning on the basis of its definition, may be useful to evaluate the performance of separation processes.View full abstractDownload PDF (269K) -
HIDETO YOSHIDA, KENZOU YAMASHITA, HIROAKI MASUDA, KOICHI IINOYA1978 Volume 11 Issue 1 Pages 48-52
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSTo examine the effect of probe diameter on isokinetic sampling errors, experimental studies were conducted using methylene blue-uranine aerosol generated by a spinning disk and lycopodium spores in the small and large inertia regions, respectively. From the results, it is found that the standard deviation of concentration ratio, defined as the ratio of concentration measured by a probe of any diameter to that by a one-cm diameter probe, is larger as the probe diameter decreases. It is also found in the small inertia region that the mean values of concentration ratio measured by smaller diameter probes are different from one another and deviate significantly from unity in some cases.View full abstractDownload PDF (357K) -
MASAAKI SAKURAI, YOSHIO HARANO1978 Volume 11 Issue 1 Pages 53-58
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSCoagulation kinetics of dispersed micro-cellulose in water were studied, using aluminum sulfate as a coagulant.
The coagulation rates in the early stage in a stirred tank were measured in terms of the "waiting time", tp, by using a light transmission measurement.
The coagulation rate constants, KB (by Brownian motion) and KF (by the velocity difference of the particles), were estimated by extrapolating l/tp against the agitation rate to the intercept and the experimental expression of the overall rate constant, K, was determined.
The KB values (obtained) agreed well with Smoluchowski''s equation. The estimated values of KF> were proportional to ε1/20, as expected theoretically, and to μ-1.2, differing from the theoretical dependence, μ-1/2. The latter deviation means a larger temperature dependency of KF in the real system than that in the theory. The order of magnitude of the coalescence efficiency, a, is also discussed.View full abstractDownload PDF (436K) -
TAKEICHIRO TAKAMATSU, YOSHIAKI SHIMIZU, TOSHIRO MURATA1978 Volume 11 Issue 1 Pages 59-66
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSThe characteristic optimal control problem for chemical processes is considered, where control variables appear linearly in system equations and inequality constraints are imposed on state variables.
Since the active constraints limit the admissible control set so as to keep the trajectory on the boundary of the constraints, some components of control variables must take interior controls. It is shown that these interior controls appear as singular controls in the conventional penalty methods and that they coincide within the limit as the parameter of penalty function rk approaches zero.
Since the appearance of singular controls is not insignificant in computation, conventional penalty methods become useless.
A new penalty method is proposed to deal with this kind of problem in general. Its validity is examined through a numerical example of chemical reactor optimization.View full abstractDownload PDF (583K) -
HISAYOSHI MATSUYAMA1978 Volume 11 Issue 1 Pages 66-67
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSDownload PDF (162K) -
VIRENDRA K. MATHUR, JAI D. SINGH, WILLIAM M. FITZGERALD1978 Volume 11 Issue 1 Pages 67-70
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSDownload PDF (330K) -
TORU IMANARA, HIKOJI INAZUMI1978 Volume 11 Issue 1 Pages 71-72
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSDownload PDF (163K) -
MASABUMI NISHIKAWA, YOSHIKAZU YONEZAWA, HIROICHI TOYODA, SHINJI NAGATA1978 Volume 11 Issue 1 Pages 73-75
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSDownload PDF (228K) -
NOBUO MITSUISHI, AKIHIRO YAMANAKA, HIROSHIGE KUMAMARU, HIROSHI KAWAKAM ...1978 Volume 11 Issue 1 Pages 75-77
Published: February 20, 1978
Released on J-STAGE: March 31, 2006
JOURNAL FREE ACCESSDownload PDF (247K)
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