Response Surface Modeling of Aerosol Release Fraction in Sodium Pool Combustion

Abstract

A response surface model has been proposed to evaluate an aerosol release fraction during sodium pool fire in a liquid metal fast reactor (LMFR). Air containing aerosols are radiative and they influence the allocation of combustion heat from the flame to atmospheric gas or sodium pool. Hence, the aerosol release fraction needs to be quantified based on the behavior of the aerosols and physics of mass and heat transfer. However, the aerosol release fraction is one of user-specified parameters of computer codes for the sodium fire safety analysis of the LMFR. In the present study, a response surface model of the aerosol release fraction has been developed based on numerical experiments of aerosol dynamics. For developing the model, aerosol dynamic equation has been solved coupled with thermal-hydraulics and chemical reaction. The authors obtained good agreement of the aerosol release fraction between the numerical experiments and the past experiments. Therefore, the aerosol behavior model has been validated with regard to the pool combustion phenomena and is reasonably applicable to the numerical experiment. Three influential variables on the release fraction are identified as pool temperature, gas temperature and oxygen molar fraction in the air. The proposed response surface model is a quadratic expression of the influential variables and can be easily employed in the sodium fire analysis code.

KEYWORDS:

• sodium pool combustion
• aerosol release fraction
• response surface
• liquid metal fast reactor
• numerical experiment safety evaluation