| Summary: | 碩士 === 元智大學 === 機械工程研究所 === 86 === Investigations of the effect of the lubricant oil on the pool
boiling heat transfer for a plain tube were carried out in this
study. The working refrigerant is R22 and the lubricant oils are
3GS and 5GS. The experiments were conducted at saturated temperatures
of -5, 4.4 and 20℃, respectively.
The results show that the ratio of the heat transfer coefficients
with the lubricant oil to that without the lubricant oil, hoil/ho,
increases as the content of oil increases at higher saturated temperatures.
However, at low saturated temperature and with low content of oil,
hoil would be greater than ho due to surface tension and bubble forming.
Besides, the effects of other parameters, such as the types of
refrigerants, the types of tube surface, the types and contents of
lubricant oil, saturated pressures and temperatures, surface tension,
and bubble foaming, on the pool boiling heat transfer coefficient
have also been studied in the present work.
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