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This paper describes research involving an in-service failure of a "variable pitch in motion" fan's blade bearing. Variable pitch in motion fans rotate at a constant speed, with the changing blade angle varying the load. A pitch-change mechanism facilitates the change in blade angle. A blade bearing supports each blade enabling it to rotate. The author observed that as the fan aerodynamic stage loading progressively increased, so did the rate of blade-bearing wear. The reported research addressed two separate, but linked, needs. First, the ongoing need to increase fan pressure development capability required an increase in fan loading. This increase was within the context of an erosive operating regime which systematically reduced fan pressure development capability. The second need was to identify the root cause of blade-bearing failures. The author addressed the linked needs using a computational analysis, improving the rotor inflow aerodynamic characteristics through an analysis of the inlet box and design of inlet guide vanes to control flow nonuniformities at the fan inlet. The results of the improvement facilitated both an increase in fan-pressure-developing capability and identification of the root cause of the blade-bearing failures. [ABSTRACT FROM AUTHOR]

In this work a simple method is developed to evaluate the design parameters of a horizontal-axis wind turbine (HAWT). The method applies the available data of an axial fan to a HAWT for the same arc profile blade in both machines. The method is illustrated by a numerical example with a complete design procedure in which the pitch angle and the chord of the blade are calculated. These calculated results agree with the measured data of a commercial HAWT blade. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Initially in this research, effects of blade inlet and outlet angles on the performance were considered by measuring performances. Twelve impellers with various blade angles were used for the measurements. The most suitable inlet and outlet angles and the inclination angle were acquired. Then, measurements on the inlet and outlet flows and their axial and circumferential distributions were taken for various operating conditions at the various measuring positions. The turning angles through the blade were calculated from these measured results. The inlet and outlet flows of the sirocco fan are not uniform around the circumference. The distributions of the flow have some relations with the development of flow in the inlet part and in the casing. Discussions were made on the flow to have a improved performance. [ABSTRACT FROM AUTHOR]