Abstract: Based on FEM numerical analysis, the flow field in atmosphere-controlled sealed box furnace with different stirring fans was simulated, and by using transient and steady-state methods, the flow velocity, static pressure and dynamic pressure changes inside the controlled atmosphere furnace were analyzed under the conditions of a four blade stirring fan (Fan4) and a six blade stirring fan (Fan6). The airflow path inside the Fan4 furnace is relatively uniform, and they are all located in the upper non-working area of the furnace. The airflow path inside the Fan6 furnace is prone to forming vortices, which have a significant impact on the uniformity of furnace temperature and atmosphere. The dynamic pressure cloud diagrams inside Fan4 and Fan6 furnaces are basically similar, and the difference in dynamic pressure within the working area is relatively small. The static pressure inside the Fan6 furnace is generally higher than that of Fan4, and under the same conditions, a six blade fan will cause the furnace pressure to be too high.

Key words: atmosphere-controlled sealed box furnace, stirring fan, flow field, numerical analysis