Studies of mechanism of noisy film boiling in He II and its control

He II 中噪声膜沸腾机理及其控制研究

• 批准号: 07455388
• 负责人: MURAKAMI Masahide
• 金额: $ 4.1万
• 依托单位: University of Tsukuba
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455388/
• 关键词: Superfluid helium; Noisy film boiling; Silent film boiling; Loud acoustic noise; Noise induced instability; Subcooled superfluid helium

The objectives of this research are the investigations of the mechanism of loud audible noise generation during noisy film boiling in He II and of the control method of it. Visualization of thermo-fluid dynamic field resulted from boiling and the measurements of the temperature by a superconductive temperature sensor and of the pressure by a pressure sensor are conducted comprehensively for the purpose. The following conclusions are drawn from the present study.(1) There are three modes of film boiling in He II appearing in the order of the hydrostatic pressure level, silent film boiling, noisy film boiling and subcool film boiling. The dependence of the onset condition of noisy film boiling on such parameters as the temperature, the static pressure and the heater size are made clear. The cause of the loud audible noise generation is found to be the explosive evaporation of He II on overheated heater immediately after the crush of a large vapor bubble on a heater surface.(2) It is foun … More d that sinusoidally oscillating thermal disturbance superposed on steady constant heat flux forces to induce the transition from silent to noisy film boiling. This indicates that the transition to noisy boiling is a kind of noise induced instability.(3) The FFT analysis result of the pressure oscillation measurement data is examined to consider the detail of the pressure oscillation caused in three film boiling modes. The high frequency (the order of kHz) components of pressure oscillation in subcool boiling are found to be resulted from the liquid column oscillation of He II in the cryostat.(4) The general feature of the transition from noisy to silent film boillings in weakly subcooled He II is made clear. At the temperatures very close to the lambda-temperature subcool boiling directly turns to silent boiling without passing through noisy boiling mode as the static pressure decreases.(5) The construction of the physico-mathematical model to describe the mechanism of noisy boiling in He II has not been completed, but sufficient amount data are accumulated for this. The control of noisy boiling is reedy to be investigated from the present experimental data. Less

本研究的目的是研究 He II 中噪声膜沸腾过程中大声可听噪声的产生机制及其控制方法，沸腾产生的热流体动力场的可视化以及超导温度的测量。为此目的，对温度传感器和压力传感器的压力进行了综合研究，从本研究中得出以下结论。（1）He II 中存在三种薄膜沸腾模式，按静水压力水平的顺序出现。默片明确了噪声膜沸腾的发生条件对温度、静压和加热器尺寸等参数的依赖性，并找出了产生较大可听噪声的原因。在加热器表面上的大气泡破裂后，He II 在过热的加热器上立即爆炸性蒸发。(2) 发现正弦振荡热扰动叠加在稳定恒定的热量上通量力引起从无声薄膜沸腾到噪声薄膜沸腾的转变，这表明向噪声沸腾的转变是一种噪声引起的不稳定性。(3)检查压力振荡测量数据的FFT分析结果以考虑细节。三种薄膜沸腾模式下压力振荡的结果表明，过冷沸腾压力振荡的高频成分（kHz量级）是由He II在液体中的液柱振荡引起的。 (4) 弱过冷 He II 中从噪声薄膜沸腾转变为无声薄膜沸腾的一般特征在非常接近 lambda 温度的温度下，过冷沸腾直接转变为无声沸腾，而不经过噪声沸腾模式，如下所示。 (5)描述He II噪声沸腾机理的物理数学模型尚未完成，但已积累了足够的数据。从目前的实验数据来看，噪声沸腾的控制亟待研究。

项目成果

Yasuo Katsuki: "Visualization study on the ons-et of film boiling and the transition to a noisy film boiling in He II" Cryogenics. 35-10. 631-635 (1995)

Yasuo Katsuki：“He II 中薄膜沸腾开始和向噪声薄膜沸腾过渡的可视化研究”Cryogenics。

M.Yamaguchi: "The investigation of vapor bubble vibration during noisy film boilimg in superfluid helium" Proc.of 16th International Cryogenic Engineering Conference (ICEC16). (1996)

M.Yamaguchi：“超流氦中噪声薄膜沸腾过程中蒸汽泡振动的研究”第 16 届国际低温工程会议 (ICEC16) 会议记录。

M.Murakami: "Study of the onset condition of noisy film boiling in superfluid helium" Proc.30th Intersociety Energy Conversion Engineering Conf.3. 301-306 (1995)

M.Murakami：“超流氦中噪声薄膜沸腾的起始条件的研究”Proc.30th Intersociety Energy Conversion Engineering Conf.3。

M.Murakami: "Thermo-fiuid dynamic aspect of noisy film boiling phenomena" Adv.Cryo.Engineering. 41A. 257-264 (1996)

M.Murakami：“噪声薄膜沸腾现象的热流体动力学方面”Adv.Cryo.Engineering。

M.Murakami: "The initial thermo-fluiddynamic process of boiling phenomena in He II" Cryogenics. 36-3. 175-181 (1996)

M.Murakami：“He II 中沸腾现象的初始热流体动力学过程”低温学。