液滴室内的氢液滴超冷条件下的结晶(英文)
Nucleation of Hydrogen Droplets in Supercooling Condition in Droplet Formation Chamber
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摘要: 液滴室内超冷现象的存在使得氢微球在自身温度低于其三相点温度的情况下依然处于液态。这可能导致液滴在真空注入过程中发生碎裂。结合液氢的超冷知识， 对液滴室内的氢液滴进行了热力学模拟， 理论上提出了利于氢液滴尽快冷却成固体小丸的最佳实验条件， 即保持液滴室内氦背景气体和氢蒸汽的压强尽可能低， 并将液滴室长度延长到6 cm以上。Because of the existence of supercooling in a droplet formation chamber, the hydrogen microspheres are still in liquid phase even though their temperature is lower than the triplepoint temperature. This may cause the droplets to shatter in the vacuum injection capillary. Based on the knowledge about supercooling of liquid hydrogen, we have done a thermodynamic simulation of the droplets in the droplet formation chamber, and theoretically suggested the optimal working conditions under which the droplets will most properly nucleate to solid pellets. The suggested working conditions are that the heliumgas pressure and the hydrogen vapor pressure in the droplet formation chamber are kept as low as possible, and the droplet formation chamber should be noless than 6 cm in the length.Abstract: Because of the existence of supercooling in a droplet formation chamber, the hydrogen microspheres are still in liquid phase even though their temperature is lower than the triplepoint temperature. This may cause the droplets to shatter in the vacuum injection capillary. Based on the knowledge about supercooling of liquid hydrogen, we have done a thermodynamic simulation of the droplets in the droplet formation chamber, and theoretically suggested the optimal working conditions under which the droplets will most properly nucleate to solid pellets. The suggested working conditions are that the heliumgas pressure and the hydrogen vapor pressure in the droplet formation chamber are kept as low as possible, and the droplet formation chamber should be noless than 6 cm in the length.
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