直接金属粉末激光烧结温度场的数值模拟研究

初步建立了用于模拟直接金属粉末激光烧结过程中传热行为的数学模型，该模型考虑了诸如传导、辐射和对流等与烧结有关的热现象。给出了固相、液相和气相共存的金属粉末烧结体系导热系数的计算方法。考虑到激光束的持续移动，采用了坐标原点位于光斑中心的动坐标系来简化方程的求解计算。在绝热边界条件和热物性参数恒定的假设下，求得了在基模高斯光束近似作用下热传导方程的解析解。运用FORTRAN语言编写了运算程序．并对铜粉激光烧结的温度场进行了数值模拟，模拟结果与初步实验结果较为吻合。

NUMERICAL SIMULATIONS OF TEMPERATURE FIELD IN DIRECT METAL LASER SINTERING PROCESS

A mathematical model is developed for simulating the heat transferring behavior in a direct metal laser sintering process. The model considers the thermal phenomena involved in the process, including conduction, radiation, and convection. A formula for the calculation of the heat conductivity of a sintering system containing solid phase, liquid phase, and gas phase is given. Due to the continuous movement of the laser beam, a local coordinate system centered on the laser beam is used to simplify the analytical calculation. Assuming that it is approximately a Gaussian laser beam, the heat conduction equation is resolved based on the assumption of the thermal insulating boundary conditions and the fixed thermal physical parameters. The FORTRAN language is employed to compile the program to simulate the temperature field in the direct copper powder sintering process. It shows a good agreement with the preliminary experimental results.