Ideal Gas Law only for substance "well removed" from phase change boundary
Do not use IGL for mixtures of stages
Do not use IGL when close to phase boundary
DO NOT USE FOR STEAM
DO NOT USE FOR LIQUIDFACTION
DO NOT USE FOR REGFRIGERATION
Processes
Isochoric
Constant Volume
dv=0
Isobaric
Constant Pressure
dP=0
Isothermal
Constant Temperature
dT=0
Isentropic
Constant Entropy
ds=0
adiabatic
reversible
Throttling
dh=0
Adiabatic
a process which takes place without any exchange of heat between a system and its surrounding
dq=0
Adiabatic dT caused by dP with no adding/subtracting of heat
Free Expansion
w=0
Reversible
No dissipative phenomena occur
Ignore viscosity effects
Impossible
Polytropic
any change in the thermodynamic properties of a gas in which its specific heat remains constant
Topic
n is polytropic index
if n = 0, then PV^0 = P = const and it is an isobaric process
if n = 1, then for an ideal gas PV = NkT = const and it is an isothermal process
if n = γ = cp/cV, then for an ideal gas it is an adiabatic process
Entropy
The unavailabilty of a systems internal thermal energy for conversion into mechanical work
Degree of randomness/disorder in the system
Enthalpy
Total heat content in a system
Used for calculating the heat transfer in a reversible process
Stagnation Properties
Quantity when a fluid is brought to rest isentropically
Adiabatically brouhgt to rest without work transfer
Removes affect of kinetic energy vatiation
Topic
Stagnation Enthalpy
Stagnation Temperature
Stagnation Pressure
Stagnation Density
Steady-flow Energy Equations
Use control volume to identify mass
describes work and heat exchange
Topic
Adiabatic -> Q=0
Non-flow Energy Equation
System of fixed mass
q-w=Δu
2nd Law of Thermodynamics
Restricts 1st Law
Entropy of an insolated system will increase over time
No 100% efficiency
Kelvin-Planck Statement
“It is impossible for any engine working in a cyclic process to draw heat from a single reservoir and convert it into work.”
Clausius Statement
“It is impossible for any engine working in a cyclic process to produce no effect other than the transfer of heat from a cooler body to a hotter body.”