A new heat transfer correlation for saturated flow boiling of water with Prandtl number improvement
A new correlation predicting the heat transfer coefficient (HTC) for the saturated flow boiling of water is presented in this study. The correlation is valid for tubes and annuli having both vertical and horizontal orientations. The fundamental aim of the study is to investigate the likely effect of the Prandtl number on the HTC for saturated flow boiling by adding the Colburn analogy into the derivation. The derivation was ended up with a new dimensionless number, hereafter called as A, and it has been suspected that A may be sensitive to the flow regime. Thanks to the comparison carried out with the flow mapping procedure of the RELAP5/Mod3.3 system analysis code, it was made prudent inference that A is dependent on the two-phase flow regimes. Rigorously evaluation of the proposed correlation makes clear that new correlation possesses admissible accuracy and that predicts the experimental HTC data with 16.6% mean deviation for saturated flow boiling. In addition,1.5% improvement in the mean deviation as per the closest correlation in which the Prandtl number effect is not considered is attributed to the positive effect of the Prandtl number improvement on HTC.
Flow boiling, Correlation, Prandtl number improvement, Flow mapping.
© 2011 Karaelmas Fen ve Mühendislik Dergisi