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

本研究的目的是探讨He II沸化过程中产生大可听噪声的机理和控制方法。为此，对沸腾产生的热流体动力场进行了可视化，并对超导温度传感器的温度和压力传感器的压力进行了全面的测量。从本研究中得出以下结论。(1) He II的膜沸腾有三种模式，依次为静水压力水平、无声膜沸腾、噪声膜沸腾和过冷膜沸腾。明确了温度、静压和加热器尺寸等参数对噪声膜沸腾发生条件的影响。发现产生巨大可听噪声的原因是在加热器表面的大气泡被压碎后立即在过热加热器上发生He II的爆炸蒸发。(2)发现，在稳定的恒热通量力的叠加下，正弦振荡热扰动引起了膜沸腾从无声到有噪声的转变。这表明向噪声沸腾的过渡是一种噪声引起的不稳定。(3)对压力振荡测量数据的FFT分析结果进行了检验，考虑了三种膜沸腾模式下压力振荡的细节。研究发现，低温沸腾过程中压力振荡的高频分量（kHz数量级）是由低温恒温器中He II的液柱振荡引起的。(4)明确了弱过冷He II由噪声沸腾向无声膜沸腾转变的一般特征。在非常接近λ温度的温度下，随着静压的降低，过冷沸腾直接变为无声沸腾，而不经过嘈杂沸腾模式。(5) He II中描述噪声沸腾机理的物理数学模型的构建尚未完成，但积累了足够的数据。从目前的实验数据来看，噪声沸腾的控制是值得研究的。少

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.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.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, T.Iida, T.Shimazaki, Y.Katsuki and T.Sato: "The initial thermo-fluid dynamic process of boiling phenomena in He II." Cryogenics. 36-3. 175-181 (1996)

M.Murakami、T.Iida、T.Shimazaki、Y.Katsuki 和 T.Sato：“He II 中沸腾现象的初始热流体动力学过程。”

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。