An improved dual-phase-lagging (DPL) model which reflects size effects caused
by nanostructures is utilized to investigate the two-dimensional thermal
conduction of nano silicon films irradiated by ultrafast laser. The integral
transformation method is used to solve the conduction governing equation
based on the improved DPL model. The variation of the internal temperature
along the thickness direction and the radial direction of the thin film is
analyzed. We find that the temperature increases rapidly in the heated
region of the film, and as time goes by, the energy travels from the heated
end to another end in a form of wave. Although both the improved DPL model
and the DPL model can obtain similar thermal wave temperature fields, the
temperature distribution in the film obtained by the improved DPL model is
relatively flat, especially for high Knudsen number. Under the same Knudsen
number, the temperature obtained by the two-dimensional improved DPL model
is higher than that obtained by the one-dimensional model, and the
temperature difference becomes larger and larger as time elapses.