• Multihole Pressure Probe;
  • Calibration System;
  • LabVIEW;
  • Reynolds Number


The multihole pressure probes are widely used to determine flow velocity vectors and pressures in the fluid machinery fields due to their robustness, convenience, and economy in flow measurement. Accuracy and fast calibration of a multihole pressure probe is very important. In this article, a multihole pressure probe automatic calibration system is developed. The hardware device mainly consists of computer, motion control equipment and data acquisition (DAQ) equipment, and the software program is developed using the G-language based on LabVIEW platform. The fundamental theory and method of multihole pressure probes is reviewed, as well as about how to take into account the compressibility effect of the fluid. The developed system can be easily integrated by engineers in research institutes or industries, without requiring more expertise in programming or multihole probe measurement method. Furthermore, the system is used for a five-hole probe's calibration and measurement, satisfactory results are obtained. 0.5° is the maximum uncertainty for the flow angles and 1.7% is for the velocity magnitude. The measurement biases being caused by the effect of Reynolds number are investigated. In the Reynolds number range of 1.06 × 104 to 4.29 × 104, the measurement biases of velocity vector are presented.