Viscosity Chart

Newtonian Fluids

The viscosity of a Newtonian fluid is dependent only on temperature but not on shear rate and time.
Examples:

* Water
* Milk
* Sugar solution
* Mineral oil

Non-Newtonian fluids, time dependent

The viscosity of the fluid is dependent on temperature, shear rate and time.
Depending on how viscosity changes with time the flow behaviour is characterised as:

* Thixotropic (time thinning, i.e. viscosity decreases with time)
* Rheopetic (time thickening, i.e. viscosity increases with time)

Thixotropic fluids are quite common in chemical as well as in food industry. Rheopectic fluids are very rare.

Note: some fluids show time thinning behaviour due to breakdown of structure. This phenomenon is somtimes known as rheomaiaxis.

Examples

* thixotropic: yoghurt, paint
* rheopectic: gypsum paste

Non-Newtonian fluids, time independent

The viscosity of a Non-Newtonian time independent fluid is dependent not only on temperature but also on shear rate.

Depending on how viscosity changes with shear rate the flow behaviour is characterised as:

* shear thinning - the viscosity decreases with increased shear rate.
* shear thickening - the viscosity increases with increased shear rate.
* plastic - exhibits a so-called yield value, i.e. a certain shear stress must be applied before flow occurs.

Sear thinning fluids are also called pseudoplastic and shear thickening fluids are also called dilatant.

Examples of shear thinning fluids:

* Paint
* Shampoo
* Slurries
* Fruit juice concentrates
* ketchup

Examples of shear thickening fluids:

* Wet sand
* Concentrated starch suspensions



Examples of plastic fluids

* Quark
* Tomato
* Tooth paste
* Hand cream
* Some ketchups
* grease

Viscosity: A measure of the resistance of a fluid to flow.

Thixotropic: Describes materials that are gel-like at rest but fluid when agitated.

Centipoise: Water is the standard at 1 cps.


MATERIAL APPROXIMATE VISCOSITY
(in centipoise)
Water @ 70 F 1 to 5
Blood or Kerosene 10
Anti-Freeze or Ethylene Glycol 15
Motor Oil SAE10 or Mazola Corn Oil 50 to 100
Motor Oil SAE30 or Maple Syrup 150 to 200
Motor Oil SAE40 or Castor Oil 250 to 500
Motor Oil SAE60 or Glycerin 1,000 to 2,000
Karo Corn Syrup or Honey 2,000 to 3,000
Blackstrap Molasses 5,000 to 10,000
Hershey Chocolate Syrup 10,000 to 25,000
Heinz Ketchup or French's Mustard 50,000 to 70,000
Tomato Paste or Peanut Butter 150,000 to 250,000
Crisco Shortening or Lard 1,000,000 to 2,000,000
Caulking Compound 5,000,000 to 10,000,000
Window Putty 100,000,000