Air Damping Analysis of a Micro-Coriolis Mass Flow Sensor

• Published in: Sensors (Basel, Switzerland) Vol. 22; no. 2; p. 673
• Main Authors: Zeng, Yaxiang, Sanders, Remco, Wiegerink, Remco J, Lötters, Joost C
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.01.2022; MDPI
• Subjects: air damping; Amplitudes; Analysis; Atmospheric pressure; Coriolis force; Coriolis mass flow sensor; Damping; Mass flow; mechanical dissipation; Pressure effects; Q factors; resonant sensors; Sensors; Signal to noise ratio; Silicon; Vibration; Netherlands; mechanical dissipation; air damping; resonant sensors; Coriolis mass flow sensor
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s22020673

A micro-Coriolis mass flow sensor is a resonating device that measures small mass flows of fluid. A large vibration amplitude is desired as the Coriolis forces due to mass flow and, accordingly, the signal-to-noise ratio, are directly proportional to the vibration amplitude. Therefore, it is important to maximize the quality factor Q so that a large vibration amplitude can be achieved without requiring high actuation voltages and high power consumption. This paper presents an investigation of the Q factor of different devices in different resonant modes. Q factors were measured both at atmospheric pressure and in vacuum. The measurement results are compared with theoretical predictions. In the atmospheric environment, the Q factor increases when the resonance frequency increases. When reducing the pressure from 1 bar to 0.1 bar, the Q factor almost doubles. At even lower pressures, the Q factor is inversely proportional to the pressure until intrinsic effects start to dominate, resulting in a maximum Q factor of approximately 7200.