An experimental study on the effect of CO₂ laser powers on melting characteristics of ice with trapped air bubbles under vertical irradiation

Icing occurs frequently and plays negative effects in natural and industrial fields. Air bubbles are always trapped in the ice during freezing, and then affect the thermal and mechanical properties of ice. As a typical non-contact and high-efficiency deicing method, laser deicing technology is tested on melting ice with trapped air bubbles, under vertical CO₂ laser irradiation and natural convection, with the laser power varied at a range of 20 ∼ 60 W. As resulted, the axial melting rate tends to increase and then decrease with increasing laser power. The maximum values of average and instantaneous axial melting rate at 40 W are 5.46 mm/s and 12.32 mm/s, respectively. At 40 ∼ 60 W, the higher the laser power, the larger the average melting length after stabilization. At 40 W and 60 W, the average melting length are 3.60 mm and 5.59 mm, respectively. It is found little correlation between the melting angle and laser power. At 30 W and 50 W, the maximum melting angles in the front view are 2.49° and 1.15°, respectively. During the whole melting process, the highest energy efficiency is maintained at 20 W, and the maximum energy efficiency is 69.1%. Results of this study could provide a reference for the application of laser deicing technology.