The Effect of Temperature on Resonant Viscosity Sensors

Miniaturized viscosity sensors are attractive devices for condition monitoring applications involving fluid media. Most recently introduced devices utilize vibrating resonant mechanical structures interacting with the fluid where the resonance frequency and the quality factor are affected by the fluid’s viscosity. The viscosity of a liquid shows a signif- icant dependence on temperature. Thus, besides a precise determination of the liquid’s temperature, the temperature dependence and stability of the sensor’s resonance characteristics and a thorough understanding and knowledge of the latter are prerequisite for accurate viscosity measurement. This contribution discusses different design approaches with respect to temperature-stable resonators.