SU510668A1 - Method for determining phase contact surface in mobile gas-liquid structures - Google Patents

Description

the bottom point ii reference electrode1, g, rpstavl / sweat point electrodes at a distance not exceeding the minimum size of gas inclusions, and periodically after 10-12 MCS compare the electrical conductors between each of the point and reference electrodes, and the surface of the contact phase is calculated by the formula

2; /;

but

g-1

where, П1 - the number of facts of inequalities of electrical conductivities between each of the point and reference electrodes; Z is the number of N-IU comparisons;

I is the distance between the electrodes, at this point the total number of such comparisons and the number of facts of the inequalities of the electron conductivities are calculated and from these data the surface of the phases is calculated.

To measure the surface contact of the mobile gas-liquid structure, two point elec- trodes 1 (Fig. 1), two thin wires of 0.15 mm diameter, electrostatically insulated and bare only at the ends, introduced into the monitored structure, and one non-insulated reference electrode are introduced into it. 2 "land The distance between the point electrodes is taken as a secant (appearing in the theory of the method of random secant), which can randomly in the process of chaotic movement of the gas-liquid structure be at the intersection of the contact of the phases or outside of it, while the point electrodes are arranged so that There is no more than the smallest gas inclusions, which need to be considered, in the opposite case such a situation is possible, when in determining the fact of intersection of the gas intersecting with the surface of the contact A new switch will occur between the point electrodes and, despite the intersection of the segments with the surface of the coil, it will not be registered.

For the foam layer, this distance is not taken, for example, to be 1 mm.

Since the gas phase is in a chaotic motion, the second moves freely relative to the structure under study. At the same time, if one of the point electrodes is at some random time in the liquid phase, and the other is in the gas phase, then the phase boundary passes between the point electrodes (the secant intersects the phase boundary) if liquid or gas, then there is no such intersection. The electrical conductivity between the point electrode, and the liquid in the liquid, and the reference electrode differs sharply from the electrical conductivity between the point electrode, which is at the same time in the gas phase, and the same reference electrode.

Thus, by the difference in electrical conductivity between each of the point electrodes and the on-electrode one, it is possible to judge whether the phase boundary between the electrodes is present or not. For this, the point electrodes are connected through a preliminary electronic amplifiers 3 and 4, which increase the sensitivity of the measurements, to a comparative electronic unit 5, which forms an electrical signal (+ 5), in the presence of a difference in electrical conductivities between each of the point and reference electrodes.

To record the fact of the intersection of the secant with the interfacial surface in random positions relative to the structure under study, and also to exclude the movement of gas inclusions relative to the electrodes at the time of such fixation by the electronic switch 6, the electronic counter 7 pulses

registering and counting the electrical nmnulses formed by the equalization unit 5, periodically connect to it in a very short period of time. For this layer, this time is 10–12 µs.

In such a short period, gas inclusions remain practically immobile with other electrodes. So, at the maximum speed of the gas plume in the foam layer, equal to 5 m / s, for 10 µs

it moves the entire ligament at 0.05 mm, which is a static condition. In the period of the connected state of the pulse counter 7 to the comparative block 5, with the help of a counter, the fact of finding the phase separation between the electrodes (if any) is recorded and summed up with other facts.

Electronic counter 8 produces an account of the total number of keys produced

for the measurement period.

Then, in formula (1), the number of calculated intersections and the number of facts of electrical conductivities between each of the point and reference points is replaced.

electrodes t, the length of the secant I by the product of the number of comparisons made 2 and the distance between the electrodes L, M. The specific surface of the contact phase is calculated by the formula

a, -, (2}

Z-LМФ Ор м у л and 3 is found and

The method of determining the phase contact surface in mobile gas-liquid structures, which consists in measuring the conductivity between the measuring and on-electrode electrodes placed in a gas-liquid structure, characterized in that, in order to accelerate the measurement process and reduce the labor intensity, from 10 to 15 microseconds, the conductivity between each

from the point and reference electrodes, and the contact phases are calculated from the form 2m

but

Z.I

where t is the number of facts of inequality

the conductance between each of the point and on-electrode electrodes; - the number of comparisons made; f is the distance between the electrodes.

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