Determination of the Viscosity by Means of the Optical Methods Utilizing the Bend Loss of the Vibrating Fiber

摘要

The systematic theoretical investigation of the optical viscometer utilizing the bend loss of fiber is carried out. The physical and mathematical model of the vibrating fiber submerged in a viscous fluid has been put forward. The impact of the viscosity and density on the resonance frequency shift has been elucidated. Based on the solution of the model simple ways of the viscosity extraction from maximum vibrational amplitude, bandwidth and the resonance frequency shift have been proposed. The theoretically achievable resolution of the viscosity sensing from a half-amplitude bandwidth with the instrumental error 2 Hz is 0.04 mPa·s for high viscous 72% glycerol-water solution.