Study ofNon-linear Wave and Quantum Phase Transition Phenomena in Superfluid Helium Performed in Superfluid Shock Tube Facility

超流激波管装置中超流氦非线性波和量子相变现象的研究

• 批准号: 11305068
• 负责人: MURAKAMI Masahide
• 金额: $ 21.7万
• 依托单位: Institute of Engineering Mechanics, University of Tsukuba
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11305068/
• 关键词: Shock Wave; Superfluid Hilium; Lambda Phsase Transition; Superfluid Shock Tube Facility; Isentropit Process; Shock Compression; Thermal Shock Wave; Khalatnikov Theory; λ-相転移; 断熱変化; エントロピ生成; 衝撃波管; λ相転移; 固体ヘリウム; 超高レイノルズ数流れ; 圧縮衝撃波; 超臨界状態; 量子; Shock Wave; Superfluid Hilium; Lambda Phsase Transition; Superfluid Shock Tube Facility; Isentropit Process; Shock Compression; Thermal Shock Wave; Khalatnikov Theory; λ-相転移; 断熱変化; エントロピ生成; 衝撃波管; λ相転移; 固体ヘリウム; 超高レイノルズ数流れ; 圧縮衝撃波; 超臨界状態; 量子

The quality of the compression nand thermal shock waves generated in the superfluid shock tube facility was found to be satisfactorily high enough for general shock wave researches. It was found that the temperature dropped in a compression shock wave and the intensity of thermal shock waves were very strong compared with those generated by pulsed heating in HeII.The velocity of the uniform flow behind a compression shock could be calculated from the visualization image with the ultra high speed video. The Reynolds number of the flow was extremely high, as high as the order of 107. This result indicates that the facility may be an alternative to the super fluid wind tunnel.The physical state of the shock compressed state at a shock front generally obeys an isentropic process in the case when the initial state of liquid helium is far from the lambda point. It is, however, found that considerable entropy production is induced in the vicinityofthe lambda line in the case where the initial equilibrium state of liquid helium is close to the lambda point. The excess entropy production was roughly in proportion to the temperature difference from the lambda point temperature.It is found from the high speed pictures that a strong density fluctuation was induced behaind a compression shock while crossing the lambda line.Some experiments are/conducted toward the experiments for solidification of He II.

发现在超流体冲击管设施中产生的压缩NAND热冲击波的质量在一般冲击波研究中足够高。发现与HEII中的脉冲加热产生的温度在压缩冲击波中降低，热冲击波的强度非常强。可以根据超高速度视频的可视化图像计算出均匀流的速度。流量的雷诺数非常高，高达107级。该结果表明该设施可能是超级流体风隧道的替代方案。当震动锋处的冲击压缩状态的物理状态通常在液体氦气远离Lambda Point的情况下，在液态氦气的情况下服从等质过程。但是，在液态氦的初始平衡状态接近Lambda点的情况下，在Lambda线附近诱导了相当大的熵产生。过量的熵产生与lambda点温度的温度差大致成比例。从高速图片中可以发现，在越过lambda线时引起了强密度波动的诱导。有些实验是/进行了用于固化HE II的实验。