Leitradlose Axialventilatoren mit verbessertem statischen Druckrückgewinn

• Antragsteller: Dr.-Ing. Christoph Bode; Professor Dr.-Ing. Jens Friedrichs
• Fachliche Zuordnung: Strömungs- und Kolbenmaschinen
• Förderung: Förderung seit 2026
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 576225047

The subject of the proposed project are rotor-only axial fans in free discharge configurations, which are used extensively in ventilation and air conditioning systems, in almost all areas of cooling technology from IT to large vehicle applications, as well as in tunnel and mine ventilation. A characteristic feature of these fans is the static pressure recovery, which takes place in the free environment in the wake of the fan. Since the mixing of the discharge flow with the surrounding air must be considered as part of the energy conversion process of the machine, static pressure recovery must also be taken into account when evaluating the aerodynamic efficiency of the fan. Accordingly, the definition of static efficiency according to ISO 5801 for installation categories A and C explicitly includes static pressure recovery by defining the ambient pressure as back pressure. In the currently available literature, the static pressure recovery has been investigated comprehensively and is usually neglected in the optimization of fan design, resulting in the minimization of the kinetic energy of the fan discharge flow (i.e., the exit loss) as a design goal. However, it is to be expected that higher exit velocities and thus higher exit losses due to a modified vortex design and hub-to-tip ratio can be expected, as these can be compensated to a certain extent by the static pressure recovery. This results in significant potential for increasing static efficiency. The aim of this project is to contribute to a comprehensive and fundamental understanding of the static pressure recovery in order to quantify this potential for efficiency improvement. For this, theoretically optimal preliminary designs are generated based on an analytical description of the static pressure recovery in a first step in order to determine the theoretical (i.e., ideal) potential for an increase in efficiency compared to the state of the art. Following this, the corresponding designs will be comprehensively examined numerically and experimentally in order to determine realistic potential for improvement by taking pressure recovery into account in the fan design. Based on these results, corresponding guidelines for fan design can be derived and evaluated in relation to the current state of research.

• DFG-Verfahren: Sachbeihilfen