Thermodynamic Units and Properties Flashcards
What are the two systems of measurement in the United States?
American Engineering System, also known as English Engineers System; and International System of Units (SI), also known as Metric System
What is a conversion factor?
A conversion factor is ratio of two equivalent physical quantities that are expressed in different units
What is a system?
A system is general term that describes quantity of matter or space that is separated from its surroundings by system boundaries
What is a working fluid?
Fluid in which energy can be stored and removed
What are properties?
Properties of substance are measurable characteristics used to describe substance
Explain the difference between intensive and extensive properties.
An intensive property is independent of mass and does not depend on how much of substance is present. 4. An extensive property depends on mass (or how much of substance is present).
State the definition of Mass.
The mass of a body is a measure of the amount of material present in that body.
State the definition of Specific Volume.
The specific volume of a substance is the volume occupied by a unit of mass of the substance.
State the definition of Density.
The density of substance is its total mass divided by its total volume. Density is reciprocal of specific volume
State the definition of Specific Weight.
Specific weight is weight per unit volume of substance.
State the definition of Specific Gravity.
The specific gravity of fluid is ratio of fluid density to density of water at 40°F (62.4 lbm/ft3).
State the definition of Temperature.
Temperature is measure of random motion of molecules of system
State the definition of Pressure.
Pressure is force per unit of area that substance exerts on its surroundings
Explain the difference between absolute and relative temperature scales.
Relative scales (F & C) are based on boiling and freezing points of water at standard atmospheric pressure. The scales provide only relative thermal energy content. Analysis of system thermodynamic properties requires absolute temperature scale with reference point corresponding to zero energy content. Both common temperature scales (F & C) have corresponding absolute temperature scales (Rankine and Kelvin)
Convert from Fahrenheit to Rankine.
Add 460 to F