Viscosity Measurement

Abstract

The most significant mechanical difference between materials classified as “fluids” and those classified as solids is in their reaction to shear stresses. This chapter begins by discussing the units by which viscosity is measured. Then the distinction between the larger field of rheology and its subfield viscometry is made in the context of differentiating between the so‐called Newtonian and non‐Newtonian fluids. The chapter provides a brief theoretical and mathematical overview of viscosity. It provides detailed and practical information on methods for measuring viscosity. The chapter develops the mathematical formulations governing viscosity, and explains the roles and relations between “shear” viscosity and “bulk” viscosity. It focuses on the use of laboratory‐type viscometers; however, some information is included on the use of process viscometers. The ASTM viscosity standards come in two types: (a) standards focused on methods (method standards) and (b) standards based on materials (material standards).

Non-Destructive Evaluation Device for Monitoring Fluid Viscosity

“…In the healthcare industry, monitoring blood viscosity is crucial for the treatment of some diseases, such as vascular-related diseases [7]. Standard laboratory viscometers, such as capillary tube and rotating ones, need long measurement times and a large volume sample [8]. Besides, rotating viscometers can be costly and require specialized training [1,8,9], and they are unable to measure viscosity in real-time continuously [1,3].…”

“…Standard laboratory viscometers, such as capillary tube and rotating ones, need long measurement times and a large volume sample [8]. Besides, rotating viscometers can be costly and require specialized training [1,8,9], and they are unable to measure viscosity in real-time continuously [1,3]. Thus, there is an increasing need for accurate, real-time, and low-cost viscosity measurement devices.…”