On the scaling of convective boiling heat transfer coefficient

Abstract

Flow boiling has been widely used during the last century, but the key mechanisms controlling the heat transfer process still remain elusive. In the particular case of convective flow boiling inside a heated pipe, most of the existing correlations have been proposed assuming an enhancement factor to the liquid Reynolds number. In this work, we show that during convective boiling heat transfer, the vapor Reynolds number plays a dominant role which has been overlooked. By comparing experimental data in this work and from the literature, we show that the enhancement factor to the liquid Reynolds number does not appropriately correlate the heat transfer coefficient. Further, it can be shown that most of the proposed enhancement factors can be re-written in terms of the explicit contribution of the ReV. In particular, at high qualities, the influence of ReL becomes negligible.