1) Summarizing the data obtained from the experiments on the mass, heat and momentum transfer relative to the pulsed flow from the inside tube wall, the authors propose to represent the fractional increments of pulsed J-factor and pulsed friction factor vs. the values of the steady flow by the following non-dimentional equations:
for mass transfer
for heat transfer,
for momentum transfer,
2) In the case of momentum transfer, however, analogical relationship of the mass and heat transfer do not show good agreement. To investigate the discrepancy. the fractional increment of friction factor was calculated from the velocity distribution of pulsed flow in the tube, resulting in the follwing qeuation.
3) From the above results, it may be concluded that the peculiar effect of pulsation on the mass and heat transfer is caused by the break in the boundary layer of the flow.

View full abstract

Performance data are given for a packed extraction-pulse column on the systems of ethylether-uranyl nitrate-water and benzene-acetic acid-water. Considering the relationship between the capacity factor and holdup of the column, the results obtained are summarized as follows:
1) Proportion of the free holdup to the total holdup is represented by the following equation, Apparent contact area is calculated from the above Xf value and dispersed drop size. The contact area increases with the increase in intensity of pulsed condition, until it attains a saturated value. The saturated point is in the vicinity of a_mX_f=25-30 [m/hr].
2) The effect of pulsation on the over-all mass transfer coefficient is much smaller than that on the cotact area.
3) The effect of column height on the over-all capacity factor depends mainly on the abnormally large valae of the over-all mass transfer coefficient of the fresh surface at the bottom of the column.

View full abstract

Studies were made on a batch vacuum crystallizer with water and aqueous solutions of Na₂CO₃·10H₂O and Na₂SO₄·10H₂O.
Exhausting rate of the rotary vacuum pump was found to follow the equation,
S=a ln P+b (1)
and the time required to reduce the pressure from P1 to P2 by a rotary vacuum pump was determined
by,
(2)
The time required to cool the solution frorn tl to t2 was fbund to be practically equal to that calculated by the following equation,
(3)
In Eq. (3), (Δt)' l.m. is to be L.M.T.D. in the temperature range of cooling water and vapor, but not so in that of cooling water and solution. This is because there exists a thermal resistance between the surface of the solution and its body.
From these considerations, the coefficient of heat transfer was obtained by the dimentional analysis, as follows:
(4)
Using Eq.(3), difference between vapor temperature and liquid temperature was obtained, and the time required for cooling the solution was determined by the use of Eqs.(3) and (4). Under certain assumptions, Equation (3) may be simplified as,
(5)

View full abstract

In computing the flow rate of Newtonian fluid in a circular pipe, the mean velocity u is calculated by the following equation:
But it takes much trouble to calculate u at a comparatively low Reynolds' number, because the discharge coefficients C or C0 have to be determined by the trial and error method. Therefore using the method of dimensional analysis the authors have derived the following relations:
Making use of the dimensionless groups mentioned above, the authors have rearranged the data published by Tuve5) and Asao, 1) and have drawn Figs.2 and 5 for DIN standard orifices, and have derived Experimental Equations (12)-(17), where D=1-6" for Equations (12), (14), (16), (17), and D=1-11/2" for Equations (13) and (15).
The authors have found that it is easier to calculate the flow rate of Newtonian fluid by Fig. 5 or Equations (12)-(17) than by using discharge coefficients.

View full abstract

Equilibrium moisture content of soap was measured under various conditions.
From these tests the following points were made clear:
i) Humidity has little influence on the drying rate of soap up to 60% relative humidity or so, but beyond this point the drying rate slows down until finally the soap begins to absorb moisture from the outside.
ii) "Milling" seems to have some influence on the binding of moisture, which shows that the vapor pressure is high.
Soap flakes were dried under various conditions and the influence of some factors were investigated. From these results it was concluded that, contrary to the common belief for drying of soap, the thinner flakes, having larger surface areas show more remarkable drying than others, in. the first drying period before the second period in which the drying rate slows down.
The so-called "case-hardening" was found to occur at relatively low humidity. In our experiments the drying time was inversely proportional to the square of the thickness, and the drying rate increased with the temperature rise, but were affected by the changes in the phase of soap.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract