Fabrication, calibration and proof experiments in hypersonic wind tunnel for a novel MEMS skin friction sensor

Abstract

MEMS skin friction sensor, used to measure skin friction and its distribution, possesses smaller volume, higher sensitivity, better stability and other merits, and is very important for air vehicles. As we all know, normal load is much larger than skin friction measured in hypersonic flow field, thus MEMS skin friction sensor applied in hypersonic conditions presents higher requirements. Basing on MEMS technologies in existence and hypersonic flow field traits, a novel skin friction measuring method and meso-scopic sensor-head microstructure, which adopt that floating element even with measured wall and signal output microstructure being isolated from hypersonic flow field, are presented. Sensor-head design, weak capacitance signal detection, MEMS process technology, static calibration and proof experiments in hypersonic wind tunnel for sensor prototypes are implemented. The results of prototype tape-out and proof experiments indicate that: the process technology scheme that meso-scopic sensor-head being divided, fabricated separately and integrated by micro-assembly is feasible, the repeatability precisions of static calibration for prototypes are better than 1.5%; sensor prototypes present stable output, better return-to-zero, higher sensitivity, and repeatability precision better than 2% in proof experiments, and provide a preliminarily feasible experimental research method for skin friction measuring in hypersonic wind tunnel.