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International Journal of Rotating Machinery
Volume 2014, Article ID 704315, 11 pages
Research Article

Effect of Chamfer Angle on the Calibration Curves of Five Hole Probes

Thermal Turbomachines Laboratory, Department of Mechanical Engineering, IIT Madras, Chennai 600 036, India

Received 30 May 2014; Accepted 28 August 2014; Published 15 September 2014

Academic Editor: Takayuki Matsunuma

Copyright © 2014 Nekkanti Sitaram and Kancherla Srikanth. 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.


Five hole probes are extensively used for measurement of total and static pressures, flow angles, velocity and its components in turbomachinery, and other aerodynamic flows. Their operating range is usually limited to 30–40° depending on the type of the probe head. The chamfer angle of the probe is usually taken around 45°. Recent studies on three hole probes have shown that 30° chamfer angle is desirable for unsteady flow measurements. Hence the present investigation is undertaken to find the optimum chamfer angle of five-hole probes. A special five-hole probe of 9.6 mm head diameter and 3 mm diameter pressure take off tubes was designed and fabricated. The large size of the probe was chosen to minimize machining inaccuracies. The probe chamfer angle was varied from 30° to 60° in 5° steps. For each of the chamfer angles, the probe was calibrated in the range of −30° to +30° in 5° interval and the calibration curves are presented. In addition the sensitivities of the calibration coefficients are determined. It is concluded that five-hole probe with a chamfer angle 30° has large operating range, while five-hole probe with a chamfer angle of 50° has good sensitivity.