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International Journal of Rotating Machinery
Volume 2014, Article ID 503579, 14 pages
http://dx.doi.org/10.1155/2014/503579
Research Article

Experimental Study of the Effect of Radially Distorted Inflow on a Contrarotating Fan Stage

Department of Aerospace Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India

Received 31 December 2013; Accepted 27 February 2014; Published 26 March 2014

Academic Editor: J.-C. Han

Copyright © 2014 Chetan Mistry and A. M. Pradeep. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The paper reports results of a detailed study of hub- and tip-strong radial inflow distortion on the performance of a low speed, high aspect ratio (3.0) contrarotating fan stage. The distortion screen (placed upstream of the first rotor) covers 1/3 of the span of the blade near the hub and the casing for hub-strong and tip-strong inflow distortions, respectively. The performance of the contrarotating fan was investigated under both the radially distorted inflows and compared with the clean inflow conditions under different speed combinations of rotor-1 and rotor-2. The hub-strong radial distortion reduces the overall performance (pressure rise and efficiency) as well as the operating range by about 2 to 4% under the different speed combinations. On the other hand, it is interesting to observe that the tip covered radial distortion not only improves the pressure rise, but also increases the overall operating range by about 6 to 8%. There was, however, a 6 to 8% decrease in efficiency in this case as compared to 12 to 15% for hub-strong radial inflow distortion. The results reveal the physics of the effects of radial inflow distortion on the overall performance of the contrarotating fan stage.