CONDENSATION HEAT TRANSFER COEFFICIENT CORRELATION BASED ON SLIP RATIO MODEL IN A HORIZONTAL HEAT EXCHANGER

摘要

Over the past few decades, there have been many experimental and analytical researches for predicting the horizontal condensation heat transfer and numerous models have been proposed. However, the proposed models that were based on the limited database, showed a considerable deviation against the experimental data, depending on authors, working fluids and flow conditions. Furthermore, since the PAFS (Passive Auxiliary Feedwater System) is a unique passive safety system adopted in the APR+ (Advanced Power Reactor Plus), conventional models showed inaccurate prediction capability on the condensation heat transfer coefficient. Experimental investigation of the condensation heat transfer and natural convection phenomena in the PAFS was experimentally investigated at KAERI (Korea Atomic Energy Research Institute). It was found that a thermal hydraulic system analysis code, MARS-KS (Multi-dimensional Analysis of Reactor Safety), underestimated the condensation heat transfer coefficient compared to the experimental data. The current study suggested a condensation heat transfer coefficient correlation using the slip ratio to model the heat transfer phenomenon inside the horizontal condensation heat exchanger. In this study, the modified correlation using the analytic slip ratio model was evaluated with the experimental data. The proposed model showed an improved prediction performance having around 8% of the error. To increase the prediction capability of the condensation heat transfer coefficient correlations developed in this study, more experimental data in the wide ranges should be compared as the further study.