Fast Response Aerodynamic Multihole Probe – Mechanism for Calibration and Possibilities for Measurements
摘要
Simultaneous measurements of 3D velocity field and pressure is of great importance. Complex air flows exist in nature, as well as in numerous technical systems. These flows exhibit high levels of turbulence, requiring high sampling rates for accurate measurement. Analyzing such flows is possible using optical methods (laser Doppler velocimetry or particle image velocimetry), hot-wire anemometry or spatial probes. The advantage of multihole probes is simultaneous measurement of 3D velocity field and pressure. The problem with optical methods is that they require laboratory conditions and they are not often used, except in special well prepared cases, on-site.Their advantage lies in non-invasiveness, high sampling rates and precision. On the other hand, standard spatial multiholeprobes are not suitable for measuring flows with high levels of turbulence. Newer generations of the multiholeprobes are capable of these measurements with fewer drawbacks. Integrating fast pressure transducers into the probe handles has enabled high sampling rates. These probes are known as FRAP (Fast Response Aerodynamic Probe). In this paper is presented five hole FRAP, mechanism and installation for its calibration. The developed half-automatic mechanism for pitch-yaw calibration in the Laboratory of the Hydraulic Machinery and Energy Systems Department, at the University of Belgrade, Faculty of Mechanical Engineering is introduced. Calibration is performed by placing the probe in a known flow field in the nozzle of the wind tunnel with low level of turbulence (less than 2%). Specified pitch-yaw calibration angles should cover all the angles of attack that will encounter during application.