E-catalog        

Here we develop a mathematical model for evaporation of an explosive thin film. Such an objective stems from the problem of trace explosive detection by techniques based on explosive vapor recording. In particular, we have previously devised an instrumentation system for standoff trace explosive detection by the active spectral imaging method. To determine the applicability limits of remote trace explosive detection methods, one should understand the regularities of evaporation dynamics of an explosive thin film, depending on explosive properties, film geometry (thickness, surface area), and ambient conditions. The mathematical model relies on the Hertz-Knudsen- Langmuir equation for evaporation rate and allows for heat exchange between the surface and ambient gas and for heat loss due to evaporation. The fact that phase transition temperature in a thin film is lower than that in a large volume of an explosive was also taken into account. The parametric study of the model was performed. The basic parameters and their variation range affecting the film evaporation rate were identified. Estimations were done for the substance mass in air during the evaporation of explosive thin films within a wide range of the parameters used. Conclusions were made on the applicability limits of trace explosive detection optical methods.