Fire simulation in large compartments with a fire model 'FDS'. Part 1. Survey of applicability for analyzing air-temperature profile in compartments

The applicability and the input parameter effects of a representative fire model, FDS, were investigated for temperature rising due to a fire in large-scale compartments under ventilation-controlled conditions in a nuclear power plant. The comparison with existing experimental results and the numerical results was made with variety of model parameters of compartment geometry, ventilation condition, heat release rate, combustion model, and grid spacing, which showed that almost all the results of the simulation agree with the experimental results within 15% deviation in terms of temperature rise. However, the difference between simulated temperatures and measured temperatures tended to be large in cases where oxygen drastically decrease in compartments or ventilation conditions are unrealistic, suggesting that the effects of the uncertainty of the model parameters of heat release rate and ventilation were larger than the effects of other model parameters such as grid spacing. Moreover, the uncertainty of the model parameter related with heat transfer on walls also largely affects numerical results, since the ratio of heat transfer on walls is high in energy balance between inside and outside of a compartment. (author)