Spherical pressure probe for retrieving freestream pressure and directional data

Abstract

A spherical pressure probe designed to time resolve the total and static pressure and freestream radial and rotational flow angles in turbomachine flow fields was found to produce accurate results for flow angles over a range of 200 in both the radial and rotational directions. Reynolds number based on the probe sphere diameter had negligible effect over the range 14,000 to 92,000. There is a weak Mach number dependence, but the probe is usable up to a Mach number of 0.90. Calibration curves are plotted for M = 0.27, 0.7, and 0.9. These results were found by calibration in steady flow. From the probe dimensions and transducer response it is judged that the probe should have frequency response better than 30 kHz.