An application of the heat transfer enhancement effect of the self-induced vibration of superfluid helium to the space observation enquipment

本研究的主要结果如下：(1)在He II的强过冷状态下，蒸汽层非常薄，并且蒸汽层的行为相对稳定。随着He II熔池压力的降低，蒸汽层的行为逐渐增强，相对稳定区逐渐缩小。在He II的弱过冷状态下，蒸汽层厚度随熔槽压力的减小而增大。在压力接近λ压力的情况下，证实了沸腾状态由稳定沸腾变为不稳定沸腾。这一边界在压力大于1压力时得到了证实。2) He II的过冷和无声膜沸腾是相同的沸腾模式，这些膜沸腾模式与普通流体中发生的正常膜沸腾相同。He II中的噪声膜沸腾是一种大规模的不稳定现象，它会在加热器温度和传热系数上产生较大的振荡，是He II的特征沸腾模式。3)He II中的弱过冷和噪声膜沸腾之间的边界存在于λ压力以上。该边界随着He II温度的降低或热通量的增加而增大。

The main result of this research would be arranged as follows1) In the strongly subcooled state of the He II, the vapor layer was very thin and the behavior of the vapor layer was relatively stable. As pressure of the He II bath was decreased, the behavior of the vapor layer was intensified gradually and the relatively stable area was diminished. And in the weakly subcooled state of the He II, the thickness of the vapor layer was increased as the decrease of the pressure of the bath. In the case of the pressure adjacent to λ-pressure, it was confirmed that the boiling state changed from stable boiling to unstable boiling. This boundary was confirmed in the pressure higher than 1-pressure.2) The subcooled and the silent film boiling in the He II are the same boiling mode and these film boiling modes are identical to the normal film boiling that occurs in common fluids. And the noisy film boiling in the He II is a kind of large-scale unstable phenomenon that generates the large oscillation in the heater temperature and the heat transfer coefficient, and it is the characteristic boiling mode in He II3) The boundary between the weakly subcooled and the noisy film boilings in He II exists just above λ-pressure. This boundary increases as the He II temperature decreases or the heat flux increases.