The works on two-phase flow were continued to investigate the liquid hold-up, flow patttern and pressure drop.
The experiments were conducted in vertical glass pipes of 8, 10.25, 12.5 and 17.5mm. i.d., employing air and various liquids under substantially isothermal condition.
The amount ratio of liquid hold-up in each pipe can be expressed by the same equation as proposed in the previous paper³⁾, and are found to be nearly independent of pipe diameter. For technical use, the following equation may be applicable within the experimental error.
Pressure gradients are almost linear at the test section, and pressure drop may be correlated with two different equations for mist and unsteady flow ranges, respectively.
For mist flow range;
For unsteady flow range;
The criteria for the transition between the above two flow ranges are roughly designated by the apparent gas velocity of 23 meters per second.

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The stress produced in a purely plastic Bingham body can be regarded as a resultant of the yield stress produced in a purely elastic body and the stress produced in a purely viscous Newtonian lipuid. From this assumption, a general differential equation for purely plastic flow has been derived, and to prove its appropriateness, a problem of plastic flow through concentric double tube has been successfully solved. The result obtained is represented as follows;
where Q: volume rate of flow,
P: pressure difference,
R₁, R₂: radius of the inner and outer tube,
l: length of the tube,
η: plastic viscosity of the material,
K: yield shearing stress,
D is a comlicated function of these variables. When using the following three non-dimensional terms,
and an equilibrium condition of solid part, it can be expressed simply as a function of a and α. Fig. 9 shows the relation between these new variables and D.
Material constants K and η were measured by the method of pulling up a long cylindrical rod slowly through the plastic material. In the method, the theoretical relation is valid,
where V and F are pulling up velocity and force, respectively.
Fig. 4 and Fig. 5, by which K and η will be easily determined, are presented, using two coupled values V₁F₁, V₂F₂, Which can be determined through experiments, and introducing non dimensional terms.
These theoretical results were proved by simple experiments.

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Experimental data on the flooding velocities in liquid-liquid countercurrent packed columns, in which aluminium Lessing rings, porcelain Raschig rings or Berl saddles are used as packings and water and three oils as liquids, are pressented.
In order to obtain a general correlation applicable to both liquid-liquid and gas-liquid systems, the results are correlated by dimensionless groups, referring to the previous literatures and the dimensional analysis. In conclusion, the pressent data and the Uchida-Fujita's data on gas (air)-liquid systems are fairly well correlated by the plot of and on a semi-log paper as shown in Fig. 1 and Fig. 2. Average line shown in these figures is experessed as follows: Y=0.60e^-2X. Fig. 3 and Fig. 4 show the comparison between the above equation and the recalculated data by the several previous investigators. It is noticed that in the calculation of gas-liquid systems the gas is always treated as the continuous phase and the liquid the dispersed phase.

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(1) The power consumption of two-blade paddle agitator is studied under varying inclination of paddle blade, depth of liquid, position of baddle and paddle size. The equation (9) bas been obtained.
(2) At Re>10⁵, the power number N_p is independent of Re unless the boss emerges out of liquid surface.
(3) When only the depth of liquid h' is variable, then N_p∞ is linear to h'.
(4) The direction of axial flow cacused by paddle inclination has no influence on the power, whether it be upwards or downwards.
(5) When the height of paddle h becomes greater than a certain value h*, the value of the power mostly remains the same, as:
h=h*
(6) The experiments are carried on only in the water.

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[in Japanese]

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