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ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

MECHANISTIC MODEL FOR NUCLEATE BOILING CRISIS AT DIFFERENT GRAVITY FIELDS

Get access (open in a dialog) DOI: 10.1615/IHTC10.4790
pages 189-194

摘要

According to the mechanistic model discussed the nucleate boiling crisis is connected with sharp expansion of dry patches area at the heated wall. It occurs when the surface - averaged heat flux becomes equal to maximum heat flux per one dry patch. The latter is defined by liquid influx to the liquid meniscus boundary which in its turn depends on the liquid properties and mean thickness of liquid macrofilm which exists under vapor blanket before boiling crisis. The mean dry patch size is supposed to be proportional to vapor bubble departure diameter. The proposed model is applicable both to pool and flow boiling and satisfactorily describes experimental results by Gambill et al who investigated boiling crisis at swirl flow in tubes. In this case the effective centrifugal acceleration is used in the correlation for pool boiling CHF instead of standard gravitational one. For high subcooling conditions the flow boiling CHF correlation based on Reynolds analogy was developed. In the case of swirl flow of subcooled liquid the critical heat flux value is chosen as a maximum one of two predictive magnitudes.