Fluid-viscosity and mass-flow sensor using forward light scattering

A novel technique of measuring liquid viscosity and air mass flow using forward light scattering from an optical fiber is being presented. The sensing principle is based on the fact that the frequency response of a partially submerged vibrating fiber probe is sensitive to viscosity and mass flow of the fluid. The viscosity and mass flow are determined by measuring the vibration of a sinusoidally excited taunted optical fiber under different flow conditions. The sensor is found to exhibit an excellent sensitivity for measuring other viscosity (liquid approximately 0.1 cP) and flow (air approximately 0.1 m/s). The sensor is also found to exhibit a high S/N ratio (> 50 dB) and stability without having any signal amplification or feedback in the system.