Abstract: The effects of a longitudinal air flow ranging in speed from quiescent to 395 m/s on the burning rate of square ethanol pools ranging in size from 4 cm×4 cm to 9 cm×9 cm were studied experimentally in a low-turbulence wind tunnel. Based on the experimental results, the mechanism of how the burning rate is affected by the air flow was discussed. The results show that for all pools tested when the flow speed is quiescent the burning rate of ethanol per unit area was basically constant. And the burning rate increased monotonically with the increase of flow air speed. The main reason for ventilation to speed up the burning rate of ethanol pool fires is that it enhances the heat feedback to the pool, which plays a far more important role than ventilation speeding up the evaporation rate by forced convection. With the increase in air flow speed, the heat feedback to the fuel surface plays an increasingly dominant role in the burning rate than that to the downward side wall of the pool.

Key words: ethanol pool fire, longitudinal air flow, burning rate, heat feedback