Glossary
to accompany
Thermodynamics: An Engineering Approach, 5th edition
by Yunus A. Çengel and Michael A. Boles3well as other losses such as heat losses to unheated areas and start-up and cool-down
losses.
Apparent gas constant of a mixture is the universal gas constant divided by the apparent
molar mass of the mixture.
Apparent molar mass of a mixture can be expressed as the sum of the products of the
mole fraction and molar mass of each component in the mixture.
Atmospheric air is the air in the atmosphere, which normally contains some water vapor
(or moisture).
Autoignition is the premature ignition of the fuel that produces an audible noise, which
is called engine knock.
Average gas constant (see apparent gas constant)
Average molar mass (see apparent molar mass)
Average velocity is the average value of the normal velocity across an entire flow cross
section and if the velocity were the average velocity all through the cross section, the
mass flow rate would be identical to that obtained by integrating the actual velocity
profile.
Back pressure is the pressure applied at the nozzle discharge region.
Back work ratio is the ratio of the compressor work to the turbine work in gas-turbine
power plants.
Bar is the unit of pressure equal to 10
5
pascal.Barometer is a device that measures the atmospheric pressure; thus, the atmospheric
pressure is often referred to as the barometric pressure.
Beattie-Bridgeman equation of state is one of the best known and is a reasonably
accurate equation of state. It is given by
where the constants for various substances are found in Table 2-4.
Benedict-Webb-Rubin equation of state is one of the more recent and very accurate
equations of state. It is given by