Experimental investigation on heat transfer performance of C-shape tube immerged in a water pool

Abstract The Passive Residual Heat Removal Heat Exchanger (PRHR-HX) is one of the key equipment of the Passive Residual Heat Removal System (PRHRS) adopted in third-generation (GEN-III) nuclear power plants. Heat transfer process of the C-shape tube applied in PRHR-HX is the combination of inside-tube condensation and outside-tube pool boiling, which is complicated and relatively differ from the most previous studies. In this paper, a high temperature and pressure two-phase flow test loop was built to investigate the heat transfer performance of an actual-size C-shape tube immerged in a water pool. The results show that both the pressure and the mass velocity influence the heat transfer characteristics significantly, while the effect of water pool temperature is not remarkable. Temperature stratifications are observed in both the water pool and the C-shape tube. Specifically, an assessment of four pool boiling heat transfer correlations is carried out to predict the experimental results of the outside-tube pool boiling. Based on the summary of the shortages of those correlations, a new correlation for the C-shape tube is developed, and also proved to be reasonable due to the experimental results.