Characterizing Vibrating Cantilevers for Liquid Viscosity and Density Sensing
Sprache des Titels:
Englisch
Original Kurzfassung:
Miniaturized liquid sensors are essential devices in online process or conditionmonitoring. In case of viscosity and density sensing,
microacoustic sensors such as quartz crystal resonators or SAW devices have proved particularly useful. However, these devices
basically measure a thin-film viscosity, which is often not comparable to the macroscopic parameters probed by conventional
viscometers. Miniaturized cantilever-based devices are interesting alternatives for such applications, but here the interaction
between the liquid and the oscillating beam is more involved. In our contribution, we describe a measurement setup, which allows
the investigation of this interaction for different beam cross-sections. We present an analytical model based on an approximation
of the immersed cantilever as an oscillating sphere comprising the effective mass and the intrinsic damping of the cantilever and
additional mass and damping due to the liquid loading. The model parameters are obtained from measurements with well-known
sample liquids by a curve fitting procedure. Finally, we present the measurement of viscosity and density of an unknown sample
liquid, demonstrating the feasibility of the model.