Performance comparison of axial fan and fan-filter unit (FFU) type clean rooms by CFD

The operational characteristics of two types of unidirectional clean room recirculation systems (i.e., an axial type clean room and a fan-filter unit (FFU) type clean room) were investigated and compared numerically. The fan performance curves and the flow resistance curves of system components were directly incorporated into the computational fluid dynamics (CFD) analysis in this study. Thus, the system operation was calculated without need of iterations for the airflow and the pressure within the enclosure to match the fan's characteristics. The fan energy was similarly incorporated into the model in order to determine the power consumption. The results show that the performance of the FFU system is generally superior to that of an axial fan system when considering factors such as uniformity of the ULPA (ultra low penetration air) filter face velocity, deflection angle of airflow in the working zone, and energy consumption.