Single-Fluid Models: Identical Working Fluid in Both Flows
PC Model
SL Model
PG Model
IG Model
RG Model
The system has two separate flows
consisting of two identical fluids, say, H2O and H2O, which can
not mix. Two inlet and two exit states - i1, i2, e1 and e2-states - are
necessary to describe the non-mixing
device. The two fluids can be chemically identical.
Two-Fluid Models: Each Flow Has a Different Working Fluid
PC Model and/or PC Model
The system has two separate flows consisting of two phase-change (PC) fluids, say, H2O and NH3, which can
not mix. Two inlet and two exit states - i1, i2, e1 and e2-states - are
necessary to describe the non-mixing
device. The two fluids can be chemically identical.
Example: Consider a heat
excahanger with R-12 and H2O being the two fluids with a possibility of
phase change for each. Suppose both the inlet states, State-1 (i1) and state-2
(i2), and one of the exit state, State-3 (e1), are completely given. For
state-4 (e2 state), set mdot4=mdot2. Set up the device analysis panel for
the known value of Wdot_ext(=0) and Qdot (=0, if adiabatic). Super-Calculate
to evaluate State-4. If T3 and T4 are both unknown, but related, iterative
solution is necessary in which Qdot is left unknown, T3 is guessed until
Qdot becomes equal to the known value.
SL Model and/or SL Model
Same as above except the solid/liquid (SL) model is used for the
two flows.
Example:A heat exchanger
with liquid water and oil being the two fluids.
PG Model and/or PG Model
Same as above except the perfect gas (PG) model is used for the two
flows.
Example:A heat exchanger
with two gases, say, N2 and O2 as the two fluids.
IG Model and/or IG Model
Same as above except the gases are modeled with the ideal gas model.
RG Model and/or RG Model
Same as above except the gases are modeled with the real gas model.
PC Model and/or SL Model
One of the fluids is modeled with the solid/liquid (SL) model and
the other with the phase-change (PC) model.
Example: A heat exchanger
with oil and steam as the two fluids.
IG Model and/or SL Model
One of the fluids is modeled with the solid/liquid (SL) model and
the other with the ideal gas (IG) model.
Example:A heat exchanger
with oil and air as the two fluids.
PC Model and/or IG Model
One of the fluids is modeled with the phase-change (PC) model
and the other with the ideal gas (IG) model.
Example: A heat exchanger
with steam and air as the two fluids.
Multi-Flow Non-Mixing Open Steady System: Governing Balance Equations
System
Animation of a mutli-flow, non-mixing, open steady system having all possible interactions with its surroundings.For specific examples of multi-flow, non-mixing, open steady systems, visit TEST.VT.Chapter-4 pages.
