SU646240A1 - Method of measuring particle-ridden gas media electric conductivity - Google Patents

Description

A flat jet of the test gas containing particles is produced in a clean jet of pure gas and a positive electrical conductivity L, the jet of clean gas is created to reduce the effects of expansion of the jet of test gas. Both jets are placed in the field created by the electrodes 1 on the one hand and the electrodes 2.3 on the other, with the potentials + Y and -Y applied to the electrodes 2.3 on fire to the ground. The field strength E, measured by electrostatic transducers 4.5 electrodes of 6.7 at the surface of electrode 1, depends both on the potentials + V and. -V and the geometry of the electrodes 1-3 and the distance between them, and the electrical conductivity of the jet of pure gas and the test gas containing particles,

When the dimensions of the electrodes are much longer than the distance between them, for a stationary distribution, when operating in ohmic mode, you can write:

(one)

EPEI

sh

where E J is the pop intensity measured at electrode 1, Ejj is the field strength created in a flat capacitor formed by electrodes 2.1, at electrode 1, Estimated the field created by the volumetric charge of the gas being studied; The charge may be present in the gas before it enters the instrument or may arise as a result of electrification during the formation of a flat jet. From the constant of current density under steady-state conditions, the slashg

(2)

with

ni

+ Eed $ Y. (3)

 +

% d current Eji eg where J is the density

sex in clean gas | EC - tension in the floor; D. n. J. Ya., Respectively, the conductivity of a frequent gas and CTpynjdj jJj, d «, are the thicknesses of a layer of pure gas and a jet with particles.

It is possible to write polaga j 2 ° 9 2g / s from equations (2) and (3);

Y

.d

(four)

with

Lg

(five)

Iii.

from 7

Hz / E is the density of the volume charge; gas scum with particles.

For the space between electrodes 3 and 1, | you can write

Hj E n- EV ((6)

where E is the field strength at electrode 1, measured by an electrostatic flux meter 7 with sensor 5, by analogy with expressions (4) and (5)

-V

EV (7)

W-iYas E 2Uj3-d

(eight)

Since CEjj.l (Ey), then after subtracting equality (6) from equality (1), it is possible, by eliminating the action of the volume coefficient, to write

 EJ -% 2Ets, (9)

From equations (2) and (3) it follows that

Yag-I,

(ten)

-2

n

eleven

whether using (9)

(L

(eleven)

Thus, the measurement of the field intensity at the indicated points allows one to determine the conductivity of the jet Я s if the conductivity of clean air Я is known. The latter can be determined by devices for measuring the electrical conduction.

To eliminate the electrode effect, the investigated and pure gases are drawn, with a certain speed exceeding the critical one, determined by the well-known formula derived for devices measuring the electrical conductivity of air,

With an increase in the jet velocity, it is possible to increase the useful signal with the help of a corresponding increase in potential and thereby increase the measurement accuracy.

The method allows to measure the electrical conductivity of a gaseous medium containing particles, such as clouds and fogs, when measured in a number of technological productions where powders are poured in the gas, which is not possible when using the scientific research institute for measuring methods used at present. 564 claims The method for measuring the electrical conductivity of a gaseous medium with particles, consisting in measuring the voltage of a capacitor field, into which a test and clean gas with a known conductivity is placed, characterized in the gas is passed inside the clean gas jet, and the field strength is measured at two points where the electric fields have opposite directions. Sources of information taken into consideration during examination 1. „Journal of Technical Physics, t, 20 N9 7, 1957, p. 8O5.