ANALYSIS OF THE INSULATION EFFECT OF CRYOGENIC VESSELS BEFORE AFTER THE FORMATION OF FILM CONDENSATION OF WATER VAPOR

The insulation failure seriously affects the economic and safe operation of cryostats. The formation of the film condensation is the direct representation of the insulation failure. A method using the comparison of the temperature of the cryogenic vessel outer surface with the drew point temperature of the air to judge the effectiveness of the cryogenic vessel vacuum is proposed. The heat transfer mechanics before and after the film condensation formation was analyzed theoretically. Experiments were carried out on a high vacuum and multiliayer insulation cryogenic vessel. The surface temperature and evaporation rates of liquid nitrogen before and after the film condensation formation were measued and analyzed. The validity and practicability of this method in judging the insulation effect is proved by results of the theoretical analysis and experimental study.