A novel five-wire micro anemometer with 3D directionality for low speed air flow detection and acoustic particle velocity detecting capability

Abstract

In this paper, a novel five-wire micro-fabricated anemometer with 3D directionality based on calorimetric principle is proposed, which is capable of measuring low speed airflow. This structure is realized by vertically bonding two different dies, which can be fabricated on the same wafer resulting in a simple fabrication process. Experiments on speed lower than 200 mm s−1 are conducted, showing good repeatability and directionality. The speed of airflow is controlled by the volumetric flow rate. The measured velocity sensitivity is 9.4 mV · s m−1, with relative direction sensitivity of 37.1 dB. The deviation between the expected and the measured directivity is analyzed by both theories and simulations. A correction procedure is proposed and turns out to be useful to eliminate this deviation. To further explore the potential of our device, we expose it to acoustic plane waves in a standing wave tube, showing consistent planar directivity of figure of eight. The measured velocity sensitivity at 1 kHz and 120 dBC is 4.4 mV · s m−1, with relative direction sensitivity of 27.0 dB. By using the correction method proposed above, the maximum angle error is about ±2°, showing its good directionality accuracy.

Design and applications of MEMS flow sensors: A review

“…The sensitivity of the sensor was determined to be 14 V/ • . In addition, Li et al developed a five-wire micro-fabricated anemometer with 3D directionality based on the calorimetric principle to detect low flow velocities and flow directionality [96]. They could achieve a velocity sensitivity of 9.4 mV/sm, with a relative direction sensitivity of 37.1 dB.…”

Three‐hot‐wire acoustic particle velocity sensor with improved detection capability

“…4 e are two key procedures which not only reduce the impact of lithography deviation on the fabrication of the ultra‐fine wires but also accelerate the lateral under‐etching of silicon under each beam by TMAH shown in Fig. 4 h [4].…”

Wall Shear Stress Sensors Based on Carbon Nanotube Pillars

“…8−10 Flow sensors further complement other measurement equipment available in experimental fluid mechanics research. 11 Arrays of miniature, surface-mounted sensors could enable time-resolved mapping of surface shear stress distributions over small geometrical features or over aircraft during operation to improve aerodynamic performance or identify turbulent, or separated flow for feedback control.…”

“…Flow sensors are widely used in process monitoring and experimental investigations of fluid dynamic phenomena, with progressive miniaturization expanding their utility to increasingly complex devices. − Reduced weight and power are essential for integration in microscale aerial and underwater autonomous vehicles to guide navigation and enable object identification. ,− Microfluidic devices require simple, reliable, microscopic flow sensors compatible with sometimes sensitive biological fluids. − Flow sensors further complement other measurement equipment available in experimental fluid mechanics research . Arrays of miniature, surface-mounted sensors could enable time-resolved mapping of surface shear stress distributions over small geometrical features or over aircraft during operation to improve aerodynamic performance or identify turbulent, or separated flow for feedback control.…”