Second sound wave heat transfer, thermal boundary layer formation and boiling: highly transient heat transport phenomena in He II
✍ Scribed by T. Shimazaki; M. Murakami; T. Iida
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 913 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0011-2275
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✦ Synopsis
Highly transient heat transport phenomena in He II are experimentally investigated. High sensitivity temperature measurements are carried out by means of a superconductive temperature sensor. It is found that the waveform of a thermal pulse in the second sound wave mode loses its dependence on heating time in the case of strong heating. Only a limited, small amount of thermal energy is transported in this mode. In such a situtation, dense quantized vortices are generated and accumulate in the vicinity of the heating surface to form a thermal boundary layer which has a large temperature gradient. The time variation of the temperature distribution in the thermal boundary layer is measured. Boiling in the layer is usually observed in the case of strong heating and the heat transport phenomena seem to be governed by boiling. The rest of the energy which is not transported in the second sound wave mode is slowly transported in a diffusive process or is consumed upon phase transition of the He II.