02-12: A Flexible Blade-to-Hub Connecting System Opposed to a Rigid Element

Abstract: Axial fans are subjected to significant loads and vibrations generated in the blade sections and transmitted to the power transmission equipment through the hub-to-blade connecting elements. In the standard configurations fan blades are rigidly clamped to the hub; in this solution high stress levels occur in the connecting elements and, generally, in all fan components. In this paper the influence of the flexibility degree of the connecting element on the reduction of loads and vibrations is discussed. Two different solutions are proposed and compared with standard solution and the results of comprehensive tests on a large fan are reported.