Virtual four sensor fast response aerodynamic probe (FRAP®)

This paper introduces the new fast response aerodynamic probe (FRAP®), which was recently developed at ETH Zurich. The provides time-resolved, three-dimensional flow measurements using virtual four sensor technique. Two probes work in tandem, being comparable to a pair of pneumatic needle probes. first probe, yaw angle sensitive, is positioned three circumferential positions. second pitch sensitive brought into exactly same position as probe. resulting set phaselock-averaged one specific rotor trigger position. Then reduced data sets are combined calibration coefficients, then further processed determine unsteady vector. results consist and angles well total static pressure. outer diameter cylindrical head miniaturized 0.84mm, hence blockage effects dynamic lift reduced. shape optimized view manufacturing process considerations. optimum geometry for sensitivity found be surface with axis perpendicular shaft. internal design led cavity eigen frequency 44 kHz 34kHz steady characteristics were measured free jet facility laboratory. full surfaces given. Data acquisition done fully automated traversing system, moves within test rig samples signal PC-based A/D-board. An error analysis implemented reduction routines revealed acceptable accuracy pressures many turbomachinery flows. Depending on application accurate ±0.35° ±0.7°. Finally, comparison time averaged five hole discussed.