Numerical Simulation of Non-Premixed Diffusion Flame and Reaction Product Aerosol Behavior in Liquid Metal Pool Combustion

Abstract

In the present study, a numerical methodology has been developed to solve a non-premixed diffusion flame under natural convection. The methodology has been applied to the calculation of the liquid sodium pool combustion experiment at various pool temperatures and oxygen molar fractions. The authors have proposed expressions of aerosol dynamics, radiation heat transfer and evaporation of liquid sodium that are applicable to sodium combustion phenomena. The computations reproduce the experimental observations concerning burning rate, flame temperature and flame height, consistently. The aerosol release fractions are also in good agreement with the measurement. Dominant mechanisms of the mass and heat transfer are identified through the numerical simulation. An intrinsic feature found in the present study is that the liquid sodium pool combustion is self-limited and a negative feedback mechanism is at work. Interaction among the thermal-hydraulics, chemical reaction and aerosol dynamic behavior plays an important role in the phenomena and it has been successfully analyzed by the numerical simulation. The present method can be used to understand sodium combustion phenomena and applied to the modeling of sodium pool combustion for safety analyses of liquid metal fast reactors. The numerical simulation is a useful tool because it can easily employ various conditions by changing parameters.

KEYWORDS:

• sodium combustion
• numerical simulation
• liquid metal reactor
• aerosol dynamics
• diffusion flame
• thermal-hydraulics
• gas radiation