焊接转子去应力热处理过程的数值模拟

Numerical simulation on stress relief heat treatment for welded disc turbine rotor

在焊接转子焊后去应力退火过程中，由于转子尺寸大、传热慢，转子内外温差较大，转子内部实际的温度场难以测试，热处理工艺参数，如加热速率、均温和保温时间、冷却速率等的制订没有可靠依据。采用扩展求解域的耦合换热计算模型，把热处理工件和热处理炉作为一个计算整体，把炉内的流体和固体都作为计算对象建立几何模型，同时考虑热处理炉内的辐射、对流和传导等换热方式，应用Fluent软件计算了热处理炉内气体和焊接转子的温度场，实现了热处理全程温度场的预测，获得了关键点的温度．时间曲线，模拟计算结果与实测结果吻合。焊接转子去应力热处理过程的模拟计算为热处理工艺设计和热处理炉控制参数的设定提供了依据。

During the stress relief annealing process for the welded disc turbine rotor, the temperature difference between inside and outside is large because of the large size and slow heat transfer of the rotor. It is difficult to measure the actual temperature field of the interior, thus it is lack of a reliable basis for design of the heat treatment process parameters such as heating rate, temperature homogenization time, holding time and cooling rate, etc. By adopting the coupled heat transfer model by extending the solution domain, taking the heat treating workpiece and furnace as a whole and all the fluid and solid in the furnace as the computation object to set up a geometric model, and considering concurrently the radiation, convection and conduction inside the furnace, the temperature fields of the welded disc turbine rotor and the gas flow in the furnace were computed by using the Fluent software, then the temperature fields of whole heat treatment process and corresponding temperature-time curves at critical points were predicted. The results show that the simulation agrees well with the measurement, and the numerical simulation on stress relief annealing for the welded disc turbine rotor provides the basis required for heat treatment process design and furnace control.