A new interpretation of data from LIFT (Lateral ignition and flame transport) apparatus and modifications for creeping flame spread

摘要

A reinterpretation of the measurements and results in the LIFT (Lateral Ignition and Flame Transport) apparatus shows that one of the parameters deduced from the existing protocol is not a material property but it is affected by the external heat flux applied at the front during the test. To reach this conclusion, a new energy balance is used to determine the creeping flame spread. By using theoretical analysis and numerical and experimental data, it is found that this energy balance properly accounts for the dual effects of external heat flux on creeping flame spread which are a) preheating of the solid ahead of the front and b) increasing the pyrolysis rate at the front. Two creeping flame spread parameters are necessary to characterize the physics in normal gravity conditions. A test apparatus simpler than LIFT is also proposed for obtaining the basic creeping flame spread properties.