NUMERICAL AND EXPERIMENTAL INVESTIGATION OF THERMAL SIGNATURES OF BURIED LANDMINES IN DRY SOIL

摘要

This paper reports a numerical and experimental investigation conducted to study the surface thermal signature of buried landmines. Numerical predictions are obtained by solving an unsteady three-dimensional energy balance model for heat transport in dry soil with a buried mine using the conservative finite-volume method. The model is validated by comparing generated results against published analytical and numerical data in addition to indoor measurements performed on dry soil inside an environmental chamber. The thermal signatures are observed while cooling takes place after exposing the soil surface to a radiant heat flux for a specified period. Transient temperature profiles produced numerically agree well with thermocouple measurements recorded at shallow soil depths and with surface IR images. The difference between predicted and measured surface temperatures is less than 0.4℃ and the difference in thermal signature is less than 0.3℃. Sit in The numerical model is also used to predict perturbations of the expected thermal signatures that are compared to the real (measured) ones from the IR images. The thermographic analysis shows good promise as a method for detecting shallowly buried land mines where not only the temperature difference or contrast images generated by the thermal signatures are matched between the IR images and the simulation images with high accuracy, but also the absolute temperatures for many images generated at discrete time intervals.