INVESTIGATION ON STEADY AND TRANSIENT STATES OF THERMAL-HYDRAULIC CHARACTERISTICS FOR A HELICAL-COILED-TYPE ONCE THROUGH STEAM GENERATOR

摘要

Helical-Coiled-Type once through steam generator (HOTSG) is considered as the first choice for its advantages in compactness and increased heat transfer in Small Modular Reactor (SMR). In this study, mathematical models of void fraction, pressure drop, and heat transfer for different boiling flow conditions in helical coil tube were presented and a computer code (OTSG-TH) for thermal-hydraulic analysis of the HOTSG was developed. Firstly, calculations were carefully validated and verified with steady-state results of ONCESG (Once Through Steam Generator) code and MRX (Marine Reactor X) experiment. Then, postulated scenarios, such as flow rate step changed in secondary side, were also calculated in this study. The results show that helical coiled tubes have higher heat transfer coefficient and fast temperature respon ds. Furthermore, the investigations on steady and transient states of thermal hydra-ulic analysis lay a foun dation for the further study on HOTSG.