L.Yu. Levin, Dr. Sci. (Eng.), Deputy director A.V. Zaitsev, Cand. Sci. (Eng.), Sector head E.V. Kolesov, engineer, kolesovev@gmail.com GI UroRAN, Perm, Russia «ГИ УрО РАН», Пермь, Россия S.V. Butakov, Director OOO NPO AeroSfera, Perm, Russia
From the analysis of the literature, three stages of the evaporation process are noted at depressurization of air conditioning system and large Freon spills. The first stage — rapid, almost instantaneous boiling in the volume of liquid due to liquid transfer to the superheated state. After this, liquid acquires the boiling point at the atmospheric pressure. The second stage — liquid boiling due to heat of the soil, which decays in the first minutes after spillage. As a result of cooling the soil temperature decreases and its upper layer begins to act as a heat-insulating layer, which prevents heat supply from the lower layers of the soil. The third stage — nonstationary evaporation from the liquid surface, which depends on its physicochemical properties, temperature and air flow mobility. This process is carried out with decrease both in temperature of the liquid surface layer and its intensity.
In the paper the speed and time of Freon emergency outflow from air conditioning system through a small aperture were estimated, the concentration of the instantly evaporated Freon during the first stage of evaporation due to liquid transfer to the superheated state was calculated, the process of spreading the cloud of the instantly evaporated Freon R-407C through the underground mining working of Mine № 3 of Taimyr mine of PAO GMK Norilsk Nickel using the AeroSet software package was simulated, the recommendations were given related to safe operation of Freon refrigerating machines in the underground air-conditioning systems — to take into account additional cases of Freon accidental leakage when developing the general plan of actions on localization and liquidation of accidents consequences.
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