Syasev V. O., Seleznova I. V., Rusakova A. V.
Oles Honchar Dnipropetrovsk National University
THE INVESTIGATION OF GAS FLOW REGIMES IN MICRO-LEAKS
In connection with constant industrial development importance, the problem of reliable sealing of the numerous installations, units and objects that are stored for a long time and work with aggressive environments or under deep vacuum, is of great importance. It is know that while operating with various facilities and structures give some, the prolonged contact with aggressive or toxic substances can leak through micro-leaks in welded or detachable joints, as well as in main material. Evaporation of aggressive substances, penetrating through the micro-leaks can lead to gas pollution of the production area environment, acceleration of the corrosion process and failure of devices and units in technological equipment, as well as health danger to the working staff .
It arises the need to study the causes and main regularities of the currents in the elements of constructions, development of reliable methods of control and improvement of technologies manufacturing of welded and detachable joints. Importance of such research lies in the impossibility of accurate measurements of the size and structure in micro-leaks, as well as various physical and chemical environment properties that affect flow regimes, and consequently, probable costs.
The leakproofness check of the gas control is used for the quantitative determination of the liquid leakage or its vapor through different micro-defects, with the help of calculating method in case of the existence coefficient transition from the magnitude of the gas flow to the liquid. Helium is usually used flow gas control .
It has been established that the loss of gas through the micro-leak affected by the pressure in the micro-leak channel, the environmental pressure, the gas physical properties and the gas leakage mode.
There aren’t any direct methods of micro-leaks determination without destroying the material. The equivalent size of micro defect can be calculated if you know the amount of flow and pressure of gas in the duct. To complete this task, the limits of flow regimes must be known .
So there were carried out numerous calculations in order to determine the boundaries of gas-flow regimes of helium, methane and nitrogen through micro ducts of different sizes. The boundaries of transition from one flow regime to another depending on the magnitude of the leak have been defined.
The list of references:
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