What is rheological Behaviour of fluid?
Rheology is defined as the study of the deformation and flow of a fluid. It is an important property of a molten polymer; it relates the viscosity with the temperature and shear rate, and is consequently linked to polymer processability.
How does a non-Newtonian fluid behave?
A non-Newtonian fluid is a fluid that does not follow Newton’s law of viscosity, i.e., constant viscosity independent of stress. In non-Newtonian fluids, viscosity can change when under force to either more liquid or more solid. Ketchup, for example, becomes runnier when shaken and is thus a non-Newtonian fluid.
What is the difference between Newtonian and non-Newtonian rheological behavior?
Newtonian fluids obey Newton’s law of viscosity. The viscosity is independent of the shear rate. Non-Newtonian fluids do not follow Newton’s law and, thus, their viscosity (ratio of shear stress to shear rate) is not constant and is dependent on the shear rate.
Is the most common type of time independent non-Newtonian fluid Behaviour?
The most common type of time-independent non-Newtonian fluid behavior observed is pseudoplasticity or shear-thinning which is characterized by an apparent viscosity that decreases with increasing shear rate.
What is Newtonian rheology?
Newtonian fluids can be characterized by a single coefficient of viscosity for a specific temperature. Rheology generally accounts for the behavior of non-Newtonian fluids, by characterizing the minimum number of functions that are needed to relate stresses with rate of change of strain or strain rates.
What is the importance of rheology?
The importance of rheology Rheology refers to the flow behaviour of materials. It depends on its properties, primarily viscosity. It is an important measurement, with some companies designing entire factory processes around single viscosity readings.
Why is rheology important in pharmacy?
Rheology is therefore crucially important as it will directly affect the way a drug is formulated and developed, the quality of the raw and finished product, the drug efficacy, the way a patient adheres to the prescribed drug, and the overall healthcare cost.
What causes a non-Newtonian fluid?
Non-Newtonian behavior of fluids can be caused by several factors, all of them related to structural reorganization of the fluid molecules due to flow. In polymer melts and solutions, it is the alignment of the highly anisotropic chains what results in a decreased viscosity.
What are Newtonian and non-Newtonian fluids with examples?
Products fall into two categories – Newtonian fluids and Non-Newtonian fluids….The Importance of Newtonian and Non-Newtonian Fluid Dynamics in Processing.
| Newtonian Fluid Examples | Non-Newtonian Fluid Examples |
|---|---|
| Motor Oil | Toothpaste |
| Water | Cosmetics |
| Gasoline | Butter |
| Cheese |
What are different types of rheological fluids?
Figure 1, non-Newtonian fluids are classified into three types: shear-thinning, viscoplastic, and shear- thickening. Characteristics of shear-thinning fluid viscosity are indicated by a decrease due to higher shear-rate. …