Abstract

In closed vessels with a cryogenic liquid, the heat gain from the environment leads to increase in the pressure in the vessel and self-heating of the liquid in the vessel. This problem is topical in storage and transportation of liquefied natural gas (LNG), for start-up refueling facilities of space rocket, and for a number of other applications of cryogenic liquids. A characteristic feature of these systems is the presence of significant temperature stratification in the upper layers of the cryogenic liquid volume. An experimental study was made of the dynamics of liquid nitrogen evaporation in a closed vessel under conditions of pressurization with helium gas up to a pressure of 0.35 MPa. The experiments were carried out in a cylindrical vessel with a height of 650 mm and an inner diameter of 213 mm at a filling of 82%. The study has shown that the stage of pressurization with helium intensifies the convective heat transfer between the interfacial surface and the vapor-gas medium in the upper part of the vessel. At the stage of subsequent heating of the liquid, two modes of heat transfer from the heat-generating walls of the vessel to the liquid are realized sequentially: with a high heat transfer coefficient at the first stage and with a significantly lower heat transfer rate at the second stage. As a result, at the stage of change of these heat transfer regimes, a sharp decrease in the intensity of liquid nitrogen evaporation is observed.

中文翻译：

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氦加压气体在密闭容器中的液氮动力学

摘要

在装有低温液体的密闭容器中，从环境中获得的热量会导致容器中的压力增加和容器中的液体自热。这个问题在液化天然气 (LNG) 的储存和运输、太空火箭的启动加油设施以及低温液体的许多其他应用中都是热点问题。这些系统的一个特征是在低温液体体积的上层存在明显的温度分层。对氦气加压至 0.35 MPa 压力条件下密闭容器中液氮蒸发动力学进行了实验研究。实验在一个高度为 650 毫米、内径为 213 毫米、填充率为 82% 的圆柱形容器中进行。研究表明，氦加压阶段加强了容器上部界面表面与蒸气-气体介质之间的对流热传递。在液体后续加热阶段，依次实现容器发热壁向液体的两种传热模式：第一阶段传热系数高，第二阶段传热速率明显降低。第二阶段。结果，在这些传热方式的变化阶段，观察到液氮蒸发强度急剧下降。从容器的发热壁到液体的两种传热模式依次实现：第一阶段传热系数高，第二阶段传热率明显降低。结果，在这些传热方式的变化阶段，观察到液氮蒸发强度急剧下降。从容器的发热壁到液体的两种传热模式依次实现：第一阶段传热系数高，第二阶段传热率明显降低。结果，在这些传热方式的变化阶段，观察到液氮蒸发强度急剧下降。