Evaluate the performance of gas power cycles for which the working fluid remains a gas
throughout the entire cycle.
Develop simplifying assumptions applicable to gas power cycles.
Review the operation of reciprocating engines.
actual and useful works are identical (Wu=W).
SECOND-LAW EFFICIENCY, II
Two heat engines that have the same thermal efficiency, but different maximum
Second-law efficiency is a measure of the performance of a thermal efficiencies. measure of
COMBINED GASVAPOR POWER CYCLES
The continued quest for higher thermal efficiencies has resulted in rather innovative
modifications to conventional power plants.
A popular modification involves a gas power cycle topping a vapor power cycle, w
The single reheat in a modern power plant improves the cycle efficiency by 4 to
5'yincreasingtheaverage 5% by increasing the average temperature at which heat is transferred
to the steam. The average temperature during the gpg reheat process
In diesel engines, only air is compressed during the compression stroke, eliminating the
possibility of auto ignition (engine knock). Therefore, diesel engines can be designed to operate
at much higher compression ratios than SI engines, typ
During an internally reversible, adiabatic (isentropic) process, the entropy remains constant.
A process during which the entropy remains constant is called an isentropic process.
Isentropic Processes of Ideal Gases Vari
Internally and Externally Reversible Processes
A reversible process involves no internal and external irreversibilities.
Internally reversible process: If no irreversibilities occur within the boundaries of the system
during the process.
Basic considerations in the analysis of power cycles
The Carnot cycle and its value in engineering
Air-standardsssumptions Airstandard sssumptions
An overview of reciprocating engines
Otto cycle: The ideal cycle for spark-ignition engines
Consider heat transfer from a system to its surroundings. How do you compare exergy changes
of the system and the surroundings?
EXERGY BALANCE: CLOSED SYSTEMS
Thh The exergy change of a system during a process is equal to the difference betwe
In a household refrigerator, the freezer compartment where heat is absorbed by the refrigerant
serves as the evaporator, and the coils usually behind the refrigerator where heat is dissipated to
the kitchen air serve as the condenser.