Contactless Pneumoelectric Fluid Viscosity Measurement Device

Abstract

We review a variety of contactless techniques for fluid viscosity measurement. We discuss contactless aero-hydrodynamic techniques capable of providing high-accuracy viscosity measurements for non-homogeneous and non-transparent fluids over the range 2–100 Pa·s. We describe a very promising approach in need of additional work–a contactless aero-hydrodynamic technique that involves using a pulsed gas jet to distort the surface of the fluid being measured and determining the viscosity based on the time required to reach a specified deformation level after the gas jet comes on. We have developed a contactless aero-hydrodynamic device with a laser triangulation detector to measure the range to the surface of the liquid; this viscosity measurement device supports full automation, while providing a significant increase in measurement accuracy. We studied four possible options for implementation of the device, and selected the best option to improve the measurement accuracy and reduce the sensitivity of the device to external effects. We describe the design and operating principle for the device, and describe how device design parameters affect systematic and random measurement error. The relative measurement error in fluid viscosity was 2% or less over the entire range from 2 to 100 Pa·s. This contactless aero-hydrodynamic device will be useful for measurement of viscous fluids in a wide variety of industrial fields.