A seven hole pressure probe measurement system and calibration method utilizing error tables

Abstract

A calibration method for seven hole pressure probes has been developed which allows simple realtime data processing and provides accuracies better than those associated with Zilliac's calibration method. The significance of the interpolation process, which is integral to Zilliac's method, has been reduced. This leaves the inherent uncertainty in the pressure transducers as the most significant factor influencing overall uncertainty in measurements. The effects of various flow conditions on the accuracy of measurements are examined. Differences in Reynolds number between a calibration and subsequent measurements are found to have an effect on accuracy. However, this effect as well as influences due to velocity gradients and turbulence intensity, are small enough that the probe can be reliably used in turbulent flows.