Water droplets irradiated by a pulsed CO_2 laser: comparison of computed temperature contours with explosive vaporization patterns

Abstract

The theoretical basis of a method which allows the computation of time-dependent temperature distributions within aerosol droplets irradiated by a laser pulse is given. The laser pulse irradiance can be time-dependent, and the temperature dependence of the droplet's conductivity, density, and specific heat is included. The algorithm is used to compute isothermal temperature contours at 305 degrees C within metastable water droplets, and these contours are compared to patterns of explosive vaporization shown in photographs of disintegrating water droplets. This comparison indicates that disintegration patterns can be explained by resistance heating if the temperature dependences of material properties are considered.