The 45~# Steel Interaction With The DF Laser Beam In Different Gas Flow

In this thesis, with experimental measurement and numerical simulation, the irradiation effects of DF laser upon 45#steel is studied in different gas flow.Firstly, experimental measurement is employed to study the effects of the DF high-power laser irradiation on 45#steel in different gas flow; by analyzing the surface picture and measuring the temperature history. The experimental results show that the gas flow cools the target when the target temperature is below the melting point. Melt removal occurs when the target temperature is upon the melting point, and combustion plays an important role in heating the material in the air flow.Then, according to the experimental results, a numerical model is established for simulating the irradiation effects of high power density laser on steel targets in different gas flow. In the case of nitrogen flow, the effects of coupling coefficient, heat conductivity, and the forced-convection heat transferring coefficient on simulation results are analyzed and then compared with experimental results to find the most favorable parameters in simulation. The method of Element birth and death is employed to simulate the ablation effects of laser on steel targets in airflow, where the effects of heat releasing by oxidation are included.