Development, Validation, and Application of the Turbulent Combustion Model for 3D CFD Code CYCAS

Abstract

The CYCAS code is a 3D CFD code developed independently by the China Nuclear Power Research Institute, aiming at hydrogen safety analysis in containments. In order to equip the CYCAS code with the capability of combustion analysis, a combustion model is screened and developed, and validated with two cases from International Standard Problems. Then a combustion analysis is conducted with a containment to demonstrate the capability of CYCAS to evaluate the pressure and thermal load of combustion. Firstly, the mature and widely-used combustion model, i.e., the Burning Velocity Model (BVM) with Zimont correlation is developed for the CYCAS code in this study. Thereafter, the lamiar flame speed correlation for CYCAS is screened based on the containment atmospheric condition during the accidents. Then, two cases from the THAI facility are calculated to validate the model. The results show that the combustion model in CYCAS manages to have reasonable prediction on the slow deflagration for the gas mixture both with and without steam. Finally, a containment combustion analysis is conducted with the initial hydrogen distribution calculated from a postulated accident. The analysis shows that the CYCAS manages to calculate the pressure and thermal load of the combustion to evaluate the influence of the combustion on the containment integrity and equipment survivability.