بخشی از پاورپوینت
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اسلاید 1 :
oTo apply the energy balance to a system of interest requires knowledge of the properties of the system and how the properties are related. The objective of Chapter 3 is to introduce property relations relevant to engineering thermodynamics. We will focus on the use of the closed system energy balance introduce in Chapter 2, together with the property relations considered in this chapter.
اسلاید 2 :
Some Concepts and Definitions
oState principal
oSimple compressible system
op-υ-T surface
o2-phase region
oTriple line
oTriple point
oSaturation state
oVapor dome
o
oCritical point
op-υ diagram
oT-υ diagram
oSubcooled (compressed) liquid
oSuperheated vapor
o2-phase liquid-vapor mixture
oQuality
اسلاید 3 :
For simple, compressible systems, the state principle indicates that the number of independent intensive properties is two.
Intensive properties such as velocity and elevation that are assigned values relative to datum outside the system are excluded from present considerations.
اسلاید 4 :
For a two-phase liquid-vapor mixture, the ratio of the mass of vapor to the total mass of the mixture is call quality, represented as x.
اسلاید 5 :
The specific volume of a two-phase liquid-vapor mixture can be determined by using the saturation tables and the definition of quality.
اسلاید 6 :
In many thermodynamic analyses the sum of the internal energy U and the product of pressure p and volume V appears. Because the sum U + pV appears so frequently, we give this combination a name, enthalpy, and a distinct symbol, H.
