Study on the Improvement of RELAP5 Post-Critical Boiling Heat Transfer Model for the Submerged Cooling Process of Rectangular Channel

Abstract RELAP5 has some shortcomings in calculating the submerged cooling process of rectangular channels, especially in the post critical heat transfer model. Based on the experimental data of submerged cooling in rectangular channel, the droplet flow precursor cooling heat transfer model, transition boiling model and minimum film boiling temperature model suitable for the submerged cooling process in rectangular channel are obtained in this paper. The secondary development is carried out on the basis of RELAP5 program, and the droplet flow precursor cooling heat transfer model, transition boiling model and minimum film boiling temperature model obtained in this paper are implanted. Through the comparative analysis of program calculation results and experimental data, the results show that the calculated values of this model are in good agreement with the experimental data, and compared with the existing calculation models, this model has good applicability to calculate the submerged cooling process of rectangular channel.