• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.5
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• pp.299-308
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• 2022

This study was conducted to predict the tendency for heat exchange and boil-off gas (BOG) in a liquefied hydrogen tank under sloshing excitation. First, athe fluid domain excited by sloshing was modeled using a multiphase-thermal flow domain in which liquid hydrogen and hydrogen gas are in the saturated state. Both the the volume of fluid (VOF) and Eulerian-based multi-phase flow methods were applied to validate the accuracy of the pressure prediction. Second, it was indirectly shown that the fluid velocity prediction could be accurate by comparing the free surface and impact pressure from the computational fluid dynamics with those from the experimental results. Thereafter, the heat ingress from the external convective heat flux was reflected on the outer surfaces of the hydrogen tank. Eulerian-based multiphase-heat flow analysis was performed for a two-dimensional Type-C cylindrical hydrogen tank under rotational sloshing motion, and an inflation technique was applied to transform the fluid domain into a computational grid model. The heat exchange and heat flux in the hydrogen liquid-gas mixture were calculated throughout the analysis,, whereas the mass transfer and vaporization models were excluded to account for the pure heat exchange between the liquid and gas in the saturated state. In addition, forced convective heat transfer by sloshing on the inner wall of the tank was not reflected so that the heat exchange in the multiphase flow of liquid and gas could only be considered. Finally, the effect of sloshing on the amount of heat exchange between liquid and gas hydrogen was discussed. Considering the heat ingress into liquid hydrogen according to the presence/absence of a sloshing excitation, the amount of heat flux and BOG were discussed for each filling ratio.

• Journal of Ginseng Research
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• v.1 no.1
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• pp.33-50
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• 1976

As a continuation of series of works on the pharmacological actions of Panax ginseng. three kinds of behavioral experiments were carried out using rats and mice. The occurrence of component Posterns of general behavioral activity in rat was examined by visual scanning using the ting sample method in the ad lib. And he hunger deprivated situation. In normal ad lib. situation, the eating behavior of rat treated with 100mg/kg of ginseng saponin was significantly more frequent than that of saline control at the night and throughout the 24 hr period. But grooming was less frequent than the control at the same period. In the hunger situation followed by 90~120 hrs of feed deprivation, the locomotive activity and rearing awe significantly more often and sleeping was less frequent in the two dosage g roups of ginseng saponin (10 and 100 mg/kg) than in the saline group though out the observation period. Training of avoidance conditioning in rats was done in a two-way shuttle box. The number of conditioned response (CR) in which the animal avoided sucessfully an electric shock by running in to the other compartment of the hex was regarded as an index of learning performance. Ginseng saponin in doses of 2.5 mg/kg Produced a significantly increased CR in total avoidance tria1s compared with the control. Although other dosage groups of ginseng saponin (5.0, 50mg and 100 mg/kg) showed no significant statistical difference from the normal control, it tended to increase in CR in the ginseng groups than in the control. An aggressive behavior in mice was observed in n shock-generating fighting box. The occurrence of reflexive fighting between two animals induced by an electric shock applied to the feet war checked as an index of aggression. The occurrence of reciprocal fighting episode immediately after the onset. Of the shock was significantly decreased in the dosage group of 400 mg/kg ginseng saponin, but it did net differ in the 100 mg/kg group of ginseng saponin from the control group. The dose, 400 mg/kg of ginseng saponin, inhibited fighting behavior in more than 80% of the Pairs. but 100 mg/kg of ginseng did inhibit it in less than 20% of the pairs.