A study on heat transfer feature and burning-decontamination rate of porous media bed soaked by combustible liquid

•The burning rate increases rapidly at first and then decreases gradually.•Dominant mechanism of heat transfer is altered (from convection-radiation to conduction), as liquid level drops.•Αn model for burning rate of porous media soaked by combustible liquid is established.•Μodel predictions agree well with the experimental measurements to some extent. This work experimentally and theoretically investigated the heat transfer feature and burning-decontamination rate of porous media environment soaked (contaminated) by leaked combustible liquid. A series of fire tests were performed employing typical combustible liquid and porous media materials. The burning rate, temperature distribution, and flame appearance, etc., were measured and identified. Results show that the variation of burning-decontamination rate of porous media bed soaked by combustible liquid can be divided into two characteristic stages, and as liquid level drops, burning rate increases rapidly and then decreases gradually. In rapid growth stage, flame thermal feedback directly could affect the burning features of top-layer combustible liquid, while in the attenuation stage, the isolation of dry porous media layer to the direct effect of flame thermal feedback and the increasing surface heat loss collectively make the burning rate attenuate. This stage-variation characteristic represents the variation of the dominant mode of heat transfer. Based on the theoretical analysis of heat transfer process in different burning stages and the empirical fitting of flame height, an explicit prediction model for burning rate is established, and the model prediction results are in reasonableagreement with most of the experimental measurements within an acceptable error range. This work provides basic data and some references for burning-decontamination technology of porous media environment (e.g., soil, sand) contaminated by combustible liquid and corresponding fire safety issues. [Display omitted]