The working substance is a phase-change (PC) fluid. That is, it can exist as a sub-cooled liquid, superheated vapor, or as a mixture of saturated liquid and vapor. Example:
Analyze a steady-flow steam turbine with one inlet and one exit.
SL Model
Constant density and constant specific heats (c_p=c_v=c) characterize the solid/liquid (SL) model. Example:
Liquid water is pumped steadily from a given inlet-state to a
given
exit-state
with no possibility of a phase change.
Gases:
PG Model
Obeys the ideal gas equation (pv=RT). Moreover, the specific heats are assumed constant. A perfect gas (PG) is a simplified ideal gas. Example: Gaseous CO2 expands steadily in a nozzle from an inlet-state
to an exit-state with no possibility of phase change.
IG Model
Obeys the ideal gas equation (pv=RT). Specific heats are temperature dependent; thus, the IG model is more accurate than the PG model. Example: Gaseous CO2 expands steadily in a nozzle from an inlet-state
to an exit-state with no possibility of phase change.
RG Model
Based on the generalized compressibility chart (pv=ZRT), the real gas (RG) model can handle a large number of fluids with different phase compositions. But generality comes at the expense of accuracy. Example: Gaseous CO2 expands steadily in a nozzle from an inlet-state
to an exit-state with the possibility of phase change.
Binary
Mixtures
The mixture contains two gases, A and B, with its composition expressed in terms of the mass or mole fraction of gas-A.
PG+PG
Model
IG+IG
Model
RG+RG
Model
General
Mixtures
Mixture can contain
any number of species
from 1 to n (n>60).
n-PG Model
n-IG Model
Single-flow Open Steady System and Its Governing Balance Equations
System
Animation of a single-flow open steady system having all possible interactions with its surroundings. A single-flow system is characterized by a single inlet and a single exit state. As a reuslt, summation signs over inlet and exit ports are no longer necessary in the balance equations. For specific examples of single-flow open steady systems, visit TEST.VT.Chapter-4 pages.
