| Summary: | Approved for public release; distribution is unlimited === Pool boiling heat transfer of nitrogen from artifical cavities was investigated. Boiling was from circular, one inch diameter horizontal mirror finished copper plates. The single artifical cavity surfaces investigate were: a drilled 0.0043 inch diameter hole, a drilled 0.015 inch diameter hole, and 0.022 nich diameter spark cut cone, and an 0.006 inch diameter spark cut cylindrical hole. The multiple cavity surfaces investigated were: seven 0.015 inch diameter drilled holes, thirteen 0.015 diameter drilled holes, and ninety-seven 0.003 to 0.0045 inch diameter spark cut holes. The depth to diameter ration was about 2.5 for all drilled cavities. The data from a mirror finished surface was compared to that of previous investigations. Exponents for Yamagata's Equation for boiling in the isolated bubble region were determined. The artificial cavities were found to affect the natural convection heat transfer. The size of the cavity appeared to have little effect after incipience of boiling, and larget cavities than previously expected were found to remain active
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