Experimental And Model Study On The Spread And Burning Behaviors Of Continuous Liquid Spill Fires

The study of continuous liquid spill fires has a great significantce to ensure the safty of liquid fuel storage and transportation.In our work,the experimental method and model analysis were used to study the mechanism of spread and burning behaviors.A burning rate model and a spread model of spill fires were developed to assess the heat flux distribution in spill fire accidents.Then a framework of quantitative risk assessment for continuous spill fires was provided.The main content is as follows:The large-scale spill fire experiments on a rectangular fireproof glass surface were conducted to study the spread process.And the entire spread process in experiments was divided into five phases: burning fuel layer spread phase,burning fuel layer shrink phase,quasi-steady burning phase,burning fuel layer boiling phase and burning extinguishment phase based on the burning area variation.The small-scale experiments of source leakage spill fires were conducted to study the burning behaviors.It is observed that the heat convection between burning spread layer and the substrate resulted in the lower burning rate,compared to that of pool fires under the same burning diameter for ethonal spill burning.For gasoline and heptane spill burning,the heat transfer between burning spread layer and the substrate,and radiative penetration were mainly responsible for the lower burning rate.The thin-layer burning experiments were conducted to study the radiative heat feedback and thermal radiative penetration through liquid layer.The result showed that the radiative heat feedback from the flame independed on the burning size in the experiments.According to the absorption characteristics,the radiative heat feedback was divided into two parts: absorption part and non-absorption part.The radiative transfer process of absorption part in liquid layer accorded to the Lambert-Beer law and the non-absorbed part could penetrate fuel layer directly.A fitting function was developed by the experimental data to calculate the radiative penetration under the different thicknesses.Based on experimental results,the burning rate model and the spread model of continuous spill fires were developed.In the burning rate analysis,the burning rate model of pool fires was modified by considerding the heat loss of liquid layer and then the burning rate model of spill fires was built.In the spread model,the burning rate was introuduced to calculate the burning amount.Then the maximum burning area could be determined for the continuous discharge.The models were then verified by the conducted experiments and the results showed the predicted values were closely to the experimental values.In the end,a framework of quantitative risk assessment was provided based on the maximum burning area and the steady burning area,which could be used to assess the personal risk for continuous discharge spill fires.Therefore,some useful information can be provided for the spill fires firefighting and the emergency rescue.