Abstract: In this paper, the variation of the prediction accuracy of the semi-empirical model of pool fire radiation with the diameter of gasoline pool fire was analyzed. The error between the calculated radiant heat flux of each combination model and the experimental has been analyzed by MATLAB value. The optimal combination model was screened out. The result verified that the prediction accuracy of classical solid flame model can be improved by using the new formula of radiative fraction ηrad presented here，and the combination of classical solid flame model and the formula of the radiative fraction presented here is optimal to predict the radiant heat flux of gasoline pool fire. When the diameter of the pool fire ranges from 0.3 to 22.3 m, the normalized mean square error between the predicted value and the experimental value is less than 0.05, the updated combination model can provide more accurate prediction than other semi- empirical models, such as Mudan model and Shokri-Beyler model.

Key words: pool fire, thermal radiation, solid flame model, radiative fraction