Numerical modeling of radiation heat transfer from combusting droplets for a sodium fire analysis

Aoyagi, Mitsuhiro ; Takata, Takashi  ; Uno, Masayoshi*

This study aims to model radiation heat transfer from combusting droplets numerically. In the modeling, radiation energy transport on the combusting area around a sodium droplet is formulated considering emission, absorption and scattering as interaction with surrounding gas radiation. Radiation energy from the combusting droplets is added to the source term of the radiation transport equation in the 6-flux gas radiation model for the multi-dimensional sodium fire analysis code AQUA-SF. Direct radiation heat transfer from combusting droplets can be simulated by this improved model. The improved model is tested through the verification analyses of single droplet combustion and the benchmark analysis on the upward sodium spray combustion experiment. The results of the test analyses show increase in heat transfer to the walls due to the droplet radiation. As the result, the sodium fire analysis becomes more reasonably by the improved model.