氦气鼓泡法获取液氢过冷度的传热传质研究

关键词:氦气鼓泡；液氢；制冷；过冷度；传热传质

关键词:  氦气鼓泡  液氢  制冷  过冷度  传热传质

Key words:  Helium gas injection  Liquid hydrogen  Refrigeration  Supercooling degree  Heat and mass transfer

摘要:

为了更好地理解氦气鼓泡获取液氢过冷度的冷却行为，优化设计冷却系统，基于集总参数法，建立了氦气鼓泡冷却系统的热力学模型，考虑了气泡界面能和压力对系统冷却效果的影响，分析了氦气注入液氢内时瞬时传热传质过程，讨论了各个影响因素。与液氢试验数据对比，热力学模型的计算值与实验值吻合良好，表明该模型可精确预测氦气鼓泡冷却液氢的热力学过程。研究了相关因素对过冷度的影响，结果表明:采用氦气鼓泡方法可将液氢过冷至三相点处；在额定工况下，氦气消耗量基本上是液氢消耗量的7倍；增加氦气鼓泡速率、降低氦气鼓泡温度、减少环境热侵、减小贮箱气枕压力，均可有效改善液氢过冷度。

Abstract:

In order to further understand cooling behaviors of helium gas injected into liquid hydrogen to optimally design cooling system，based on the lumped parameter method，a thermodynamic model for the cooling system of helium gas injection considering with effect of bubble interface energy and pressure was established，the instantaneous heat and mass transfer process of helium gas injected into liquid hydrogen was analyzed，and various influencing factors were discussed. Comparing with the experimental data of liquid hydrogen，it is verified that the calculated results of the thermodynamic model are in good agreement with the experimental results，which fully reflects that this model can accurately predict the thermodynamic process of helium gas injected into liquid hydrogen. The influence of relative factors on the supercooling degree is investigated. The study shows that the helium bubbling method can be used to cool liquid hydrogen to the triple point. Under rated conditions，helium consumption is basically 7 times that of liquid hydrogen consumption. It can effectively improve the supercooling degree of liquid hydrogen to increase the injection rate of helium，reduce the injection temperature of helium，decrease the environmental leakage heat，and diminish ullage pressure.