viscosity of a Newtonian fluid is dependent only on temperature but
not on shear rate and time.
Non-Newtonian fluids, time dependent
viscosity of the fluid is dependent on temperature, shear rate and 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.
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:
Sear thinning fluids are also called pseudoplastic and shear thickening fluids are also called dilatant.
Examples of shear thinning fluids:
Examples of shear thickening fluids:
Examples of plastic fluids
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.
|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|