ISSN Online: 2379-1748
ISBN Flash Drive: 978-1-56700-469-4
ISBN Online: 978-1-56700-470-0
Second Thermal and Fluids Engineering Conference
SPECTRAL ABSORPTION OF NEAR-INFRARED LASER IRRADIATION IN WATER DROPLET
Abstract
Employing the Monte Carlo method, the spectral absorption characteristics of water droplet with different
diameters under near-infrared laser irradiation is numerically investigated. The typical wavelength of the
incident laser beam is 980 nm and 1985 nm, and the laser beam is regarded as collimated radiation, and the
radiant energy is considered as two forms, Gaussian distribution and Uniform distribution. After verifying the
computation method with literature on one dimension radiation absorption, the total absorptivity and internal
absorption characteristic of the water droplet are obtained. The total absorptivity of the water droplet is low at
980 nm, with the radius from 0 to 2.0 mm. Due to the high spectral absorption coefficient, the total absorptivity
of the water droplet at 1985 nm is different from that of at 980 nm, which increases sharply when the radius
changes from 0 to 0.3mm, and maintains about 0.93 when the radius is larger than 0.3 mm. The transport
direction of the incident laser beam with parallel direction changes after entering the water droplet, and the
concentration phenomenon appears. The absorbed radiant energy mainly locates at the opposite direction where
the near-infrared laser enters into the droplet at 980 nm, and exists in the entrance at 1985 nm.