Criteria and comparison of thermal stratification between PRHR HX heating and ADS spraying process in IRWST based on a down-scaled experimental facility

摘要

The overall scaled-down separate-effects IRWST&PRHR HX&ADS test facility has been built to simulate the thermal hydraulic behavior of the passive residual heat removal system under accident conditions. The measured 3-D temperature and velocity results show obvious thermal stratification in IRWST. The Richardson number (Ri) could be used to predict the occurrence of possible thermal stratification, and the Stratification number (Str) to evaluate the thermal stratification extent. Both dimensionless parameters provide criteria for thermal stratification and experimental references for the design and operation of engineering equipment.