What is glass capillary viscometer?
A capillary viscometer is an instrument used to measure the viscosity, or thickness, of a liquid by measuring how long it takes the liquid to flow through a small-diameter tube, or capillary.
How does a glass capillary viscometer work?
#2 — Capillary viscometers They’re straight-forward and simple to use, consisting of a U-shaped glass tube with two bulbs (one higher and one lower). Fluid passes from the higher bulb to the lower bulb through a capillary, and viscosity is measured by timing how long it takes the fluid to pass through the tube.
What is the drawback of capillary viscometer?
The shear stress and shear rate at the wall are no longer constant, the shear stress decreasing and the shear rate increasing as the liquid flows down the capillary. As a result, the calculation of even an apparent viscosity gives a value that has questionable meaning.
What are the examples of capillary viscometer?
Usage Examples Capillary viscometers are used to measure the viscosity of a wide range of diverse fluids. Common examples include petroleum products, lubricants, adhesives, and sealants.
What is SI and CGS unit of viscosity?
The SI unit of dynamic viscosity is the newton-second per square meter (N·s/m2), also frequently expressed in the equivalent forms pascal-second (Pa·s) and kilogram per meter per second (kg·m−1·s−1). The CGS unit is the poise (P, or g·cm−1·s−1 = 0.1 Pa·s), named after Jean Léonard Marie Poiseuille.
How do viscometers work?
Viscometers usually work by comparing a stationary object and a fluid flow, or vice versa. Hence, a viscometer could be placed in a fluid flow or moved through a stationary fluid. The flow must have a Reynolds number in the laminar region in order to record accurate values.
What is capillary viscosity?
Viscosity is generally temperature dependent, so the capillary viscometer is usually used in a controlled-temperature water bath set to a specific temperature. Viscosity may be thought of as the internal friction of a liquid, or its tendency to resist flowing. Viscosity is thus an important property of fluids.
What are the types of viscosity?
There are two types of viscosity: dynamic viscosity, measured in pascal seconds, and kinematic viscosity, measured in metres per second squared. Viscosity is used as a way to predict when volcanoes erupt.
What is capillary rheometer?
Capillary Rheometer. The capillary rheometer (or viscometer) is the most common device for measuring viscosity. Gravity, compressed gas or a piston is used to generate pressure on the test fluid in a reservoir. A capillary tube of radius R and length L is connected to the bottom of the reservoir.