FLUIDS MECHANICS AND FLUID PROPERTIES
Bilal Ahmad Malik
Department of Mechanical Engineering, Techno Global University, Meghalaya.
Email: bilalmalik15@gmail.com
Introduction
What is fluid mechanics? As its name suggests it is the branch of applied mechanics concerned with the statics and dynamics of fluids – both liquids and gases. The analysis of the behavior of fluids is based on the fundamental law of mechanics which relate continuity of mass and energy with force and momentum together with the familiar solid mechanics properties.
Objectives Define the nature of a fluid. Show where fluid mechanics concepts are common with those of solid mechanics and indicate some fundamental areas of difference. Introduce viscosity and show what Newtonian and non-Newtonian fluids are. Define the
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colloidal substances like clay, milk and cement. Dilatant substances: Viscosity increases with rate of shear e.g. quicksand. Thixotropic substances: A Viscosity decrease with length of shear force is applied e.g. thixotropic jelly paints. Rheopectic substances: Viscosity is increases with length of time shear force is applied. Viscoelastic materials: Similar to Newtonian but if there is a sudden large change in shear they behave like plastic.
There is also one more – which is not real, it does not exist – known as the ideal fluid. This is a fluid which is assumed to have no viscosity. This is a useful concept when theoretical solutions are being considered – it does help achieve some practically useful solutions.
Liquids vs. Gasses Although liquids and gasses behave in much the same way and share many similar characteristics, they also possess distinct characteristics of their own. Specifically, A liquid is difficult to compress and often regarded as being incompressible. A gas is easily to compress and usually treated as such – it changes volume with
Mixing sodium polyacrylate and water resulted in in a thick, clear gel that resembled ice or snow. It was sticky and wouldn’t form a shape if you held it in your hand and molded it. Adding heated water and sprinkling in poly(vinyl alcohol) to the surface of the water produced another sticky
The general chemical characteristic of gas equilibriums is when the concentrations of reactants and products do not change with time. This is known as the state of reversible reaction. At this state, pressure, density, colour and concentration can be recognised. At equilibrium, both the forward and backward reactions are still continuing because the rates of the forward and backward reactions are equal. This leads to the general physical characteristic of gas equilibriums which is the concentration of each substances become constant and the system is said to be at dynamic equilibrium. The equilibrium can be established in physical equilibrium and in chemical equilibrium.
In a phenomenon termed the “hydrophobic effect”, 4 surfactants act the way they do in
The range of application of the original Boltzmann equation has grown way beyond just dealing with a rarefied gas with one constituent and as a result, several generalizations of the Boltzmann equation have been developed and this includes the reactive Boltzmann
When a substance undergoes a triple point change, then it goes through all three of the states of matter: solid, liquid, as well as gas. When all three matters exist at the same time, it is extremely rare and an interesting sight to experience. A triple point is defined, specifically, as “ the temperature and pressure at which the solid, liquid, and vapor phases of a pure substance can coexist in equilibrium” (1). An excellent example of a substance that has the ability to obtain a triple point would be dry ice. Dry ice is solid CO2. Dry ice has many uses, which include keeping items frozen for a long period of time. This is because dry ice is simple to freeze, stays cold, and has a temperature of “-109.3°F or -78.5°C” (2).
Oil- Is a liquid at room temperature and is generally comes from a plant origin.
On earth, substances tend to exist in one of three phases; either a solid, liquid, or gas. While solids and liquids have defining factors such as volume, and for solids only, a shape, gases exhibit neither of these. Gases naturally take the shape of and expand into the volume of the container, and change when placed in different surroundings. As gases are constantly moving around and colliding with the walls, they exert a force, or pressure, on the walls of its container. Pressure is one of the characteristic behaviors that gases exhibit, but due to their nature, various factor effect the pressures that a gas can exert. Towards the end of the eighteenth century, scientist began to stumble upon these various factors that affect gases, especially
The task of this lab is to create and analyze hypotheses of the different relationships between the properties of gasses. These properties include temperature, pressure and volume. The ideal gas law is the source for many of these hypotheses and are tested through the various known laws of gasses. Such laws include Lusaacs Law, Charles Law and Boyles Law. The data, gathered from the results of the experiments mentioned above, was then graphed to show the relationship between the properties that gasses inhibit. The data provided was also utilized to derive a proportionality constant, k. Pressure rises when temperature rises, pressure rises when volume falls and volume rises when temperature rises. All of these outcomes were observed during the
The shear viscosity is a transport coefficient for momentum in inhomogeneous flows. This transport coefficient, which is widely used to describe both plasmas and fluids, relates two hydrodynamic quantities: shear stress and shear rate. The shear stress Pxy is the off-diagonal element of a pressure tensor, and the shear rate γ is the transverse gradient of the flow velocity u. For a flow in the y direction,
The viscosity of pure liquids affects on temperature, pressure, density, and surface tension (Dutt et al, 2007). When the temperature drops the particles slow down and come closer together, the forces of attraction between them will increase and so make it harder for them to flow past each other. Thus, Dynamic viscosity of liquids increases with decreasing temperature (Binder et al, 2007).
This form of Henry’s Law can be used up to a pressure of about 200 kPa and liquid concentrations of 1 mol% (Carroll, 1991). This shows that at low partial pressures a plot of mole fraction of a compound vs. partial pressure of the compound in the g...
The comparison between the vapour compression and vapour absorption systems are given in Table 1
Ultrasonic is the universally accepted technique to study the physico-chemical properties of the liquids, liquid mixtures, electrolytic solutions and polymeric solutions. Liquids, liquid-mixtures and solutions find wide applications in medical, pharmaceutical, chemical, lather, textile, nuclear and solvent, solution related industries. The study and understanding of the thermodynamic properties of liquid mixtures and solutions are more essential for their applications in these industries. The measurements of ultrasonic velocity in the combination of density and viscosity have been used to study the molecular interactions in liquid mixtures and solutions.
Surface Tension: The contractive tendency of a liquid that allows it to resist an external force. This is measured in Newton.