How Rheometers Can Do More Than Just Go With The Flow

There are many industries and professions in which it is essential to monitor the quantity and characteristics of the flow of liquids or forces, from the petroleum industry to medical practices. In these instances, rheometers are incredibly helpful. While today's rheometers are intended for highly specific tasks, the word has meant different things throughout the course of history, and has evolved greatly from its origins into what we know of as a rheometer today.

The word rheometer is derived from Greek roots, and means simply a device to measure flow. This classification was originally incredibly broad, referring not only to liquids, but also indicating the flow of electricity. As time passed and fields evolved, specific types of rheometers gained their own unique names. Eventually rheometers measured only the flow of liquids and, upon the coining of the word rheology, were finally used only to describe the characteristics of a liquid's flow rather than its quantity.

Rheology is the study of the ways in which matter flows. In many instances, the properties of this flow are well understood. We can, for instance, predict the flows of substances such as oil or pure water reasonably well. When additional variables are introduced however, such as impurities in the water or a material of unknown or unusual composition, the characteristics of this flow simply cannot easily be known.

To help in modeling the flow, it is essential to discover certain characteristics of the substances involved. For instance, viscosity has a rather large impact on how materials flow, determining whether a given substance attains a smooth surface or maintains changes over long periods of time. Understanding these variables is key to creating models of how materials of different composition will flow, and rheometers are the primary instruments by which these are discovered.

In general, these products create flows of liquids using known mechanisms and in known environments. In other words, they don't simply make one liquid flow through another and study the results. Rather, they place some quantity of liquid in anenvironment of known size and, often by rotation or some other well-measured means, try to make the liquid flow.

One type, the capillary rheometer, forces fluids through a pipe of known dimensions at an established pressure. By doing so and observing the results, this type of product can discover the sheer rate or sheer stress of a liquid being tested.

Other types of rheometers rotate liquids in two cylinders. An inner cylinder contains the liquid itself, while the outer cylinder is empty. The force of the liquid rotating within the inner cylinder exerts a certain amount of force to rotate the outer cylinder, creating torque. This, in turn, can be converted into sheer stress, one of many variables that can help model the liquid's flow.

Rheology has many applications in a variety of industries. It can help to discover the best types of drilling fluids to use when working on oil wells, or to model the flow rate and quality of oil through other substances. It is used in studies of the magma layer beneath the earth's surface, or in medical laboratories. Rheology plays a vital role in each of these areas, and rheometers are at the forefront of both groundbreaking research and everyday practical solutions.