How do you determine co-efficient of viscosity of pure liquid?

Answer 1

First of all, you have to break it apart. What is Viscosity?=thickness, stickyness, how it moves. To measure the thickness, you can either slide something down a slanted platform, or drop a marble into each jar of the liquids that you are comparing. To measure the stickyness, it would be a good idea to put cardboard on the two sides of the liquid, and stretch them apart, and see what happenes. Lastly, to measure how it moves: try and poor the liquids you are trying to compare down a slanted platform, and see how it moves.

There isn't really something that can measure exact levels of viscosity.

In conclusion, you can't get exact measurements of viscosity, but you are able to find out which liquid has the most viscosity, and which one has the less.

Viscosity is the measure of fluidity a liquid exhibits - meaning how thick or how thin it is.

Viscosity of liquid newtonian substances can be measured by measuring the time a liquid moves in a graduated tube from Point A to Point B at a given temperature usually 20oC

Collodial substances can be measured using a graduated cup. The time taken for the liquid to drain out of the cup. the end time taken when the liquid stream breaks.

In dilute solutions, an Ubhellode Tube is used. Here again, the time taken for a volume of liquid to pass from Point A to Boint B.

In polymer melts, viscosity (melt viscosity) is done by measuring the torque of a synchronised stirrer in the molten polymer at a certain temperature. Example by using the Broofield Melt Indexer

Thanks

Sachinder Paruth

Tekmation Training Institute

Jacobs

South Africa

Answer 2

consider two layers of fluid from a fixed layer. Then according to Newtons Law of viscosity, the viscous force(F) acting tangentially is directly proportional to the area of the layer(A) and is also directly proportional to dv/dx.

F directly proportional to A..................(1)

F directly proportional to dv/dx...................(2)

therefore from (1) and (2)

F directly proportional to Adv/dx

removing proportionality sign, we get

F=coefficient of viscosity multiplied by Adv/dx

hence,

coefficient of viscosity =Fdx/Adv

Answer 3

In general, in any flow, layers move at different velocities and the fluid's viscosity arises from the shear stress between the layers that ultimately opposes any applied force.

Isaac newton postulated that, for straight, parallel and uniform flow, the shear stress, τ, between layers is proportional to the velocity gradient, ∂u /∂y, in the direction perpendicular to the layers.

Here, the constant μ is known as the coefficient of viscosity, the viscosity, the dynamic viscosity, or the Newtonian viscosity.

This is a constitutive equation (like Hooke's law, Fick's law, Ohm's law). This means: it is not a fundamental law of nature, but a reasonable first approximation that holds in some materials and fails in others. Many fluids, such as water and most gases, satisfy Newton's criterion and are known as Newtonian fluids. Non-Newtonian fluids exhibit a more complicated relationship between shear stress and velocity gradient than simple linearity.

Answer 4

From Wikipedia:

Viscosity coefficients can be defined in two ways:

Dynamic viscosity, also absolute viscosity, the more usual one (typical units Pa·s, Poise, cP);

Kinematic viscosity is the dynamic viscosity divided by the density (typical units m2/s, Stokes, cSt).

Answer 5

The coefficient of viscosity of a pure liquid can be determined by measuring the force required to move a plate through the liquid at a constant speed, and then calculating the ratio of shear stress to shear rate. This can be done using instruments such as a viscometer or a rheometer. The coefficient of viscosity is a measure of the liquid's resistance to flow.

Answer 6

Viscosity is the state of a material when it is thick and sticky and does not flow easily.

Answer 7

BY viscous flow through a capillary tube or by Stoke's method.

Answer 8

The viscosity of materials is not calculated but measured with some instruments, especially viscosimeters.

Answer 9

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