Specific
Closed-Process Cycle Daemons: Select Working
Fluid Model
HOME.
Daemons.
Systems.
Closed.
Process.
Specific.
Cycles
Launch
the Daemon by Choosing a Model.
A Phase-Change Fluid
The working substance is a phase-change
fluid. That is, it can exist as a super-cooled liquid, superheated
vapor or as a mixture of saturated liquid and vapor. Example:
Steam is executing a closed cycle in a piston cylinder device.
Gases:
A Perfect
Gas
Obeys the ideal gas equation
(pv=RT). Moreover the specific heats
remain constant - a simplification at the expense of accuracy. Example:
Cold air standard Diesel cycle with specific heats assumed constant.
An Ideal
Gas
Obeys the ideal gas equation
(pv=RT). Specific heats are temperature dependent; thus, the model is more
accurate than the perfect gas model. Example:
Air standard Otto cycle with variable specific heats for better accuracy.
A Real
Gas
Based on the generalized compressibility
chart (pv=ZRT), the real gas model can handle a large number
of fluids in their liquid, vapor or gaseous states. But generality comes
at the expense of accuracy. Example:
Unless the cycle exhibits possibility of a phase change, use of this model
will produce inaccuracies that can be avoided by using the ideal gas model.
Binary Mixtures
Mixture of two gases, A and B, it is expressed
in terms of the mass or mole fraction of gas-A.
Two
Perf. Gases
Two
Ideal Gases
Two
Real Gases
General Mixtures
Mixture can contain any number of species
from 1 to n (n>60).
