A non-Newtonian fluid does not have a specific viscosity and remains constant, but changes with the heat energy and shear force applied to it. These fluids are characterized by the study that is done when they are deformed, which occurs through the application of force. These components appear when there is a relationship between stress and stress. Therefore, they work under various flow conditions, such as those of shear type stress. Next, we will see what non-Newtonian fluids are.
Meaning of non-Newtonian fluids
The viscosity of a non-Newtonian fluid is not fixed, since it changes when temperature and shear stress are imposed on it. Instead, the viscosity of a Newtonian fluid is based on temperature and is described as a function of pressure, without the aid of additional forces. Unlike Newtonian fluids, non-Newtonian fluids lack a constant value and viscosity.
A non-Newtonian fluid is a homogeneous substance in its composition and undergoes deformation continuously, this occurs when a force is applied. They are usually substances do not have a unique shape and take the shape of the container in which they are found. There are different types of non-Newtonian fluids, such as the following:
- The plastics.
- Fluids influenced by viscosity and time.
- The viscoelastics.
- The fluids that follow the power law.
What are the characteristics of non-Newtonian fluids?
The following features are essential to define a non-Newtonian fluid:
- A static non-Newtonian fluid behaves like a liquid but if force is applied to it, its viscosity increases. By imposing force on its surface, the added stress causes a rearrangement of the atoms, resulting in increased viscosity and the ability to momentarily behave like a solid.
- It is homogeneous consistency.
- Does not have a viscosity value constant nor fixed.
- presents endurance.
- liquids have the ability to change your behavior depending on the voltage applied to them.
- viscosity generally depends on the weather.
- Also it depends on the temperature.
- The fluid is characterized by its viscosity.
- Your behavior It is influenced by the applied force.
- Time is another factor relevant to their behavior.
What is the difference between non-Newtonian and Newtonian fluids?
There are various differences between Newtonian and non-Newtonian fluids. Next, we will mention the distinctive characteristics of Newtonian fluids:
- They do not have elastic elements or unreal.
- They are liquid.
- They are based on Newton’s law. on viscosity, which implies a linear relationship between strain rate and shear stress.
- do not present flow resistance.
- They have a viscosity definite and constant.
- viscosity remains constant under stress.
- viscosity does not depend on the application time of the effort, but yes of the temperature and the pressure.
- viscosity decreases as it increases temperature.
- They can contain various elements in its composition, depending on the case.
Some examples of Newtonian fluids are: air, water, wine, gasoline and mineral oils. Here are the distinctive features of non-Newtonian fluids:
- have a consistent and homogeneous substance.
- They do not have a viscosity definite or constant.
- They can behave as both solids and fluidsand are not based on any Newton’s law.
- Its resistance to flow is variable and depends on time and applied force. The effort causes changes in viscosity.
- may include biological fluids.
- HE used in the production of soapsfood, natural substances, among others.
Examples of Non-Newtonian Fluids
Some examples we can mention are:
- Mayonnaise: It is a cold emulsion made from blended vegetable oil and egg.
- Paint: It is the prime example of non-Newtonian fluids and is composed of solvents, pigments, and binders.
- Varnishes: They are formed by solvents, such as oils or resins.
- Jams and jellies: They are cooked fruit preserves based on sugar and are made up of starch.
- Polymer Solutions: They are liquid compositions that contain small solvent molecules and are used to specify the structure of polymers. They are also used to control rheological properties in foodstuffs, paints, and pharmaceuticals.
- Butter: It is a substance derived from milk that is obtained by beating, kneading and leaving the cream to ferment. It is used in the manufacture of butter.
- Caramel sauce: It is a very popular milk-based preparation in Latin America. It has a caramelized consistency and is used in numerous desserts such as cakes, waffles, pastries, etc.
- Honey: It is a sweet, viscous liquid produced by bees, especially domesticated bees of the genus Apis, from the nectar of flowers or from secretions of plants or animals that feed on flowers.
- Sauces: It refers to liquid or thick preparations that have a specific flavor. Recipes for making sauces are found in cookbooks.
- Molasses: Also known as honey or blackstrap, they are produced by crystallizing sugar and obtained by cooking sugar cane.
- Solutions of water with clay and soap: They are important examples, and their consistency will depend on the amount of water added, which will determine their thickness.
- Human blood: In biology, blood is one of the most important non-Newtonian fluids. It flows through veins, arteries, and capillaries in vertebrates. Red blood cells contain hemoglobin, a pigment that gives them their characteristic red color.
- Magma and lava.
- Cement and mud.
- biological science: Saliva, synovial fluid, and mucosa are also examples of non-Newtonian fluids.
Some applications of non-newtonian fluids in hydraulics include:
- Vibration dampers: Some non-Newtonian fluids, such as magnetorheological fluids and electrorheological fluids, are used in vibration damping systems. These fluids can change their viscosity in response to magnetic or electric fields, allowing vibration damping to be adjusted and controlled in real time.
- Flow control: Non-Newtonian fluids can be used to control flow in hydraulic systems.
- Sealing and lubrication: Some non-Newtonian fluids, such as lubricating gels and pastes, are used for sealing and lubrication in hydraulic systems.
- Transport of solids: Non-Newtonian fluids are also used in applications where it is necessary to transport suspended solids, such as slurries, concrete mixes, and mineral slurries.
How to make a non-Newtonian fluid?
An example can be given of how a fluid of this type is made. In this case, we can use cornstarch. To prepare it, follow these steps:
- take a big bowl.
- Pour a full glass of water in the bowl.
- add the cornstarch little by little until a thick texture is obtained.
- Knead the mix gradually.
Once the mass is homogeneous, you will be able to observe the behavior of the fluid. If you leave it at rest, you will see that the mass behaves like a liquid, it may even seem to melt when held in your hand. Also, it will start to move and even drip. However, when you hit it hard, you will notice that it behaves like a solid, being hard and not staining your hands. Other examples of processes to obtain non-Newtonian fluids are:
- soapy solutions.
- Toothpaste.
- sludge.
- Yoghurt.
- Butter.
- Cement.
Unlike non-Newtonian thixotropic and rheopectic fluids, dilatant liquids change their viscosity as a function of applied energy, not time. The harder you hit the fluid, the more viscous it will become.
The results of this study can be used to develop proper operating procedures with the aim of improving productivity. This system could be a hydraulic system thermodynamic that works with water at high pressure and flow to control the flow and pressure.
