HEAT TRANSFER CORRELATION FOR BOILING FLOWS IN VERTICAL RECTANGULAR NARROW CHANNEL

摘要

In view of the practical significance of a correlation of heat transfer coefficient in the aspect of such applications as engineering and predictive, some efforts towards correlating flow boiling heat transfer correlation for vertical rectangular narrow channels have been made in this paper. Based on analyses of existing general correlations for flow boiling heat transfer, it is found that general correlations are not suitable to predict heat transfer coefficients in narrow channels. By considering the suppression factor S and two-phase pool boiling heat transfer coefficient h_(nb) , introducing boiling number Bo and two-phase friction multiplier Φ_(tt)~2, the Chen correlation has been modified to be used for narrow channels. The flow boiling heat transfer was the function of boiling number Bo and two-phase friction multiplier Φ_(tt)~2 , the coefficients have a regular change with the increase of boiling number Bo or two-phase friction multiplierΦ_(tt)~2. A comparison of the newly developed correlation with the existing data for narrow channels shows a satisfactory agreement. The heat transfer coefficient of the narrow channel was well predicted by the new correlation and the deviation within ±20%.