SU1504506A1 - Method of determining sizes of through-going microcapillari - Google Patents

Abstract

This invention relates to a measurement technique and can be used to control end-to-end ultramicrocapillaries in partitions. The purpose of the invention is to determine the number and radii of ultramicrocapillaries. On the one hand, the partitions fill in the light boiling liquid wetting it and create pressure, and on the other hand, the flow rate of the liquid penetrating the controlled ultra-microcapillaries is determined by the composition of the gaseous medium. The number of stepwise increases in fluid flow is taken as the number of ultramicrocapillaries, and their radii are calculated based on experimental dependencies taking into account the ratio of pressure drop across the septum at the time of stepwise flow rate growth and at the beginning of the linear dependence of flow rate on the pressure drop and liquid.

Description

The invention relates to a measurement technique and can be used to determine the number and radii of through ultramicrocapillaries with a cross section of less than 0.1 µm in partitions made of metallic and nonmetallic materials separating a light boiling liquid and a gaseous medium, such as ultramicrocapillaries in body parts. containers made by casting or composite materials.

The purpose of the invention is to determine the number and radii of ultramicrocapillaries.

The cavity, located on one side of the controlled partition, is filled with an easy boiling wetting

liquid, and from the cavity on the other side of the septum, gas flow is determined by gas analysis through the septum. The liquid fills the ultramicrocapillaries and elastic forces arise between its particles and the surface of the partition in the boundary layer, preventing the liquid from flowing from the liquid into the gas cavity. Therefore, only boiling liquid vapor penetrates through the burnout by diffusion.

Then smoothly draw the pressure of the fluid. When the pressure drop across the septum between the liquid and gas cavities exceeds the elastic force acting in the ultramicroc

SP

Od

31

The largest flow area through this channel begins the flow of the gash, which is plotted on the graph of the flow rate versus pressure drop as a stepwise increase in flow rate at a definite pressure drop.

Continuing to increase the pressure of the fluid, other pressure drops are recorded at the moments of the onset of a stepped increase in the flow rate of the fluid, which indicates the beginning of the flow of fluid through the ultramicrocapillaries of smaller and smaller flow sections. The number of ultramicrocapillaries is equal to the number of stepped increases in liquidity expenses. Upon reaching the linear dependence of the flow rate of the liquid on the pressure drop, the differential pressure is set to DFd. The calculation of the radii of the capillaries is determined from the experimentally found ratio

G., .S-1-.P ;.

where g; - radius of the 1st capillary; S - thickness of the boundary layer

liquids; LR | - pressure differential between

liquid and gaseous medium at the moment of i-ro step and tjaToro growth of fluid flow; URd - pressure drop between

liquid and gaseous medium at the time of the beginning of the linear dependence of the liquid flow rate on the pressure drop

The thickness S of the boundary layer of the liquid is determined experimentally from the ratio given with a known radius of the capillary.

For example, nitrous oxide is used as a light boiling liquid, and orthotolidine reagent is used as a gas analyzer. The ultramicrocapillaries with a radius of 0.03 μm and 0.05 μm in a partition of stainless steel 12X18H10T were controlled. Liquid nitrogen tetroxide is poured on one side of the nepes-town, and indicator paper is periodically applied to the other side, which under the action of nitrogen tetroxide changes color. The nitrogen tetroxide consumption is determined by the area of the color spot. The pressure of nitrogen tetroxide and the graphical dependence of its flow rate on pressure drop are increased. The graph shows a stepwise increase in flow rate at a pressure drop of 6 atm and 12 atm and the beginning of a linear dependence of nitrogen tetroxide flow on a pressure drop at a drop of 21 atm. It was established experimentally that the thickness of the boundary layer of liquid nitrogen tetroxide on the surface of stainless steel is 0.07 microns.

The calculation of the radii of ultramicrocapillaries for the proposed dependence confirms the acceptable accuracy of the proposed method.

Thus, determining the sizes of ultramicrocapillaries from the pressure drop across them at the time of the stepwise increase in flow rate allows us to establish the number of ultramicrocapillaries and their radii.

Formula of invention

The method of determining the sizes of the through ultramicrocapillaries in the partitions separating the light boiling liquid and the gaseous medium, the pressure of the liquid is measured, the flow through the partition is measured, and the size of the ultramicrocapillary is determined by it. informativity due to the determination of the number and radii of ultramicrocapillaries; in the process of pressure increase, pressure differences between the liquid and the gaseous medium are recorded at times of stepwise

the growth of fluid flow and the onset of linear dependence of fluid flow on pressure drop, take the number of ultramicrocapillaries equal to the number of stepped ages, the flow rates of the fluid, and the capillary radii are determined from the ratios

55

G;

8-.- I- Р.

where g; - i-ro radius of capillary; S is the thickness of the boundary layer of the liquid;

515045066

AR; - pressure drop between 4Rd - pressure drop between

liquid and gaseous ec-liquid and gaseous medium

doi at i-ro time

a partial increase in the flow rate of the liquid-dependence of the fluid flow rate} of the bone on the pressure drop.

Claims (1)

Claim The method for determining the size of through ultramicrocapillaries in the partitions separating the low-boiling liquid and the gas medium, which consists in increasing the pressure of the liquid, measuring its flow rate through the baffle, and determining the size of the ultramicrocapillaries, which is characterized in that, in order to increase the information content by determining the number and radii of ultramicrocapillaries, in the process of increasing pressure, pressure drops are recorded between the liquid and the gas medium at the moments of a stepwise increase in the liquid flow and at the time of and the linear dependence of the fluid flow on the differential pressure takes the number of ultramicrocapillaries equal to the number of stepwise increases in fluid flow, and the radii capillaries are determined from the ratios ^g '“ ⁵ yR _l where r; - radius i-ro capillary; 8 - boundary layer thickness liquids; pressure difference between the liquid and the gaseous medium at the moment of i-ro stepwise increase in the liquid flow rate; & R _D - pressure drop between the liquid and the gas medium at the time of the start of the linear dependence of the fluid flow on the pressure drop