Flow boiling—the ‘apparently nucleate’ regime

This paper re-examines the nucleate boiling term in the Chen correlation (ASME Paper 63-HT-34 (1963)) for the heat transfer coefficient in flow boiling, which he derived from a correlation then current for pool boiling. The re-examination employs all available data published for water, with results of a recent simplified analysis of pool boiling which used reduced pressure (Advances in Heat Transfer, Vol. 16, pp. 157–239 (1984)), and also employs additional data from flow boiling experiments at Oxford, in which the ‘apparently nucleate’ regime can be distinguished with some confidence. It is concluded that a term based on the new pool boiling analysis would probably be better as well as simpler, but, in view of the extremely wide scatter present in these and all other nucleate boiling data, there is no strong case for altering existing calculation methods based on the term derived by Chen.