Conduction and Convection of Heat Produced by the Attenuation of Laser Beams in Liquids

Abstract : Mathematical models are used to simulate temperature changes that are induced by the absorption of energy from propagating laser beams in water. Both convective and conductive heat transfer are considered. Thermally insulated surfaces as well as surfaces involving heat transfer with the surroundings are considered. The simulated results demonstrate the importance of thermal convection. In the first part of this report containers with closed surfaces are considered. In the second part of the report free-surface effects are considered: These effects include evaporative heat loss and the occurrence of surface tension produced by temperature gradients at the surface (the Marangoni effect). Evaporative heat loss is simulated and the Marangoni effect is discussed. The quantitative determination of the temperature changes in the water due to the heat transferred by an absorbed laser beam could facilitate the improvement of models involving the optics of laser beam penetration in liquids.