Introduction edit
Gas dynamics is the overview of the average value in the distance between two molecules of gas that has collided with out ignoring the structure in which the molecules are contained. The field requires a great amount of knowledge and practical use in the ideas of the kinetic theory of gases, and it links the kinetic theory of gases with the solid state physics through the study of how gas reacts with surfaces[1].
Definition of a Fluid edit
Fluids are substances that do not permanently change under an enormous amount of stress. A solid tends to deform in order to remain at equilibrium under a great deal of stress. Fluids are defined as both liquids and gases because the molecules inside the fluid are much weaker than those molecules contained in a solid. When referring to the density of a fluid in terms of a liquid, there is a small percentage of change to the liquid’s density as pressure is increased. If the fluid is referred to as a gas, the density will change greatly depending on the amount of pressure applied due to the equation of state for gases (p=ρRT). In the study of the flow of liquids, the term used while referring to the little change in density is called incompressible flow. In the study of the flow of gases, the rapid increase due to an increase of pressure is called compressible flow[2].
Real Gases edit
Real gases are commonly referred to as ideal gases. Real gases are characterized by their compressibility (z) in the equation PV=zn0RT. When the pressure, P, is set as a function of the volume, V, where the series is determined by set temperatures, T, P and V began to take hyperbolic relationships that are exhibited by ideal gases as the temperatures start to get very high. A critical point is reached when the slope of the graph is equal to zero and makes the state of the fluid change between a liquid and a vapor (Fig 19 p.50). The properties of ideal gases contain viscosity, thermal conductivity, and diffusion[3].
Viscosity edit
The viscosity of gases is the result in the transfer of each molecule of gas as they pass each other from layer to layer. As gases tend to pass one another, the velocity, in the form of momentum, of the faster moving molecule speeds up the slower moving molecule. As the slower moving molecule passes the faster moving molecule, the momentum of the slower moving particle slows down the faster moving particle. The molecules continue to enact until frictional drag causes both molecules to equalize their velocities[4].
Thermal Conductivity edit
The thermal conductivity of a gas can be found through analysis of a gas’ viscosity except the molecules are stationary while only the temperatures of the gases are changing. Thermal conductivity is stated as the amount of heat transported across a specific area in a specific time. The thermal conductivity always flows opposite of the direction of the temperature gradient[5].
Diffusion edit
Diffusion of gases is configured with a uniform concentration of gases and while the gases are stationary. Diffusion is the change of concentration between the two gases due to a weaker concentration gradient between the two gases. Diffusion is the transportation of mass over a period of time[6].
References edit
- ^ Cercignani, Carlo. Preface. Rarefied Gas Dynamics: from Basic Concepts to Actual Calculations. Cambridge UP, 2000. Xiii. Print.
- ^ John, James Edward Albert., and Theo G. Keith. Gas Dynamics. Harlow: Prentice Hall, 2006. 1-2. Print
- ^ Turrell, George. Gas Dynamics: Theory and Applications. Chichester: J. Wiley, 1997. 45-53. Print
- ^ Turrell, George. Gas Dynamics: Theory and Applications. Chichester: J. Wiley, 1997. 31-33. Print
- ^ Turrell, George. Gas Dynamics: Theory and Applications. Chichester: J. Wiley, 1997. 33-34. Print
- ^ Turrell, George. Gas Dynamics: Theory and Applications. Chichester: J. Wiley, 1997. 34-35. Print