Theoretical Research on DNB-type Critical Heat Flux with Non-Uniform Axial Heat Flux Distribution

Based on the liquid sublayer dryout mechanism, an improved mechanistic DNB-type critical heat flux（CHF） model has been developed for non-uniform axial heat flux distribution. In this DNB-type critical heat flux model, the non-uniform heat flux in axial is taken into account of upstream memory effect on thermalhydrlics characters at boiling crisis point; the boiling crisis is triggered when the liquid sublayer underneath vapor blanket is completely dried out by the local heat flux on the wall; and the position of boiling crisis is confirmed by comparing the CHF predictions at each potential boiling crisis points. The prediction results of the present CHF model and empirical correlations with correction factors are verified by non-uniform heating CHF experimental results, which are obtained with inlet-peak, center-peak and outlet-peak power profiles. The comparisons show the present model has more reasonable capability on predicting DNB-type CHF and boiling crisis position under non-uniform heating condition than the correction factor method.