Demonstration of leakage flow distribution of an axial fan inside the tip clearance gap

The tip leakage flow and its associated losses one of the key parameters influence the performance of the axial turbomachines. In this paper, the tip leakage distribution of an axial industrial fan was demonstrated for different stagger angles, tip clearance, and volumetric flow rates. In all stagger angle cases, the demonstration of the tip leakage flow confirmed that there is a part of the leakage flow moves from the blade suction side to the pressure side. The negative leakage zone becomes bigger and more intense as the stagger angle increase. This zone became stronger and more obvious in the bigger stagger angle cases. Furthermore, for both stagger angle cases, the leakage flow had a peak zone located inside the tip clearance gap. The bigger stagger angle cases had the largest and most intense peak leakage zone compared to the other stagger angle cases. Moreover, in all cases, there was a low-velocity zone near the blade tip surface is known as leakage separation zone. The size and strength of this zone varied significantly based on the operation condition. The demonstration of the leakage flow at the tip clearance has given a clear demonstration of the leakage flow structure distribution for different flow rates, tip clearances, and stagger angles.