Current status of CHF predictions using CFD modeling technique and review of other techniques especially for non-uniform axial and circumferential heating profiles

Trusted predictions of critical heat flux (CHF) value are essential for safe operation of boilers, steam generators and nuclear power reactors. Prediction techniques are numerous but they are mostly limited to uniformly heated tubes. There are separated effects on CHF, such as axial and radial heat flux distributions that have not been taken much attention. These effects are encountered during operation of boilers/steam generators and nuclear reactors. The present work is aimed at providing detailed analysis for experimental and numerical techniques used in CHF predictions focusing on non-uniform axial and circumferential heating profiles. For this purpose, heat transfer characteristics in case of CHF and heat transfer and wall boiling modeling are also clearly described. In addition, a detailed description of numerical models used in the predictions of the two phase flow characteristics is also presented followed by addressing most of the numerical work done for predictions of CHF in literature. Due to new challenges presented by the non-uniform heating in axial and circumferential directions, research work pertaining to analysis of CHF predictions in real systems for non-uniform heating profiles in both axial and circumferential directions is also presented.