Reversible and Irreversible Processes Flashcards
What is an isentropic process?
A process that doesn’t produce any entropy
What is the isentropic equation that relates Temperature and Specific Volume?
T2 / T1 = (v1 / v2) ^ (k-1)
What is the isentropic equation that relates Temperature and Pressure?
T2 / T1 = (P2 / P1) ^ (k-1/k)
What is the isentropic equation that relates Pressure and Specific Volume?
P2 / P1 = (v1 / v2) ^ k
What is the value of k?
cp / cv
What is the standard value of k for air?
k = 1.4
What is a Carnot Engine?
This is a theoretical, reversible heat engine that eliminates all irreversibilities, so it has the greatest possible efficiency
What are the necessary processes in a heat engine?
- Heat Addition
- Work Production
- Removal of Waste Heat
- Compression
How is heat transfer made reversible?
Isothermal heat transfer is totally reversible. So if we have a temperature difference of approximately 0, then we will have a reversible reaction
What are the four processes in a Carnot engine?
- Isothermal Heat Addition
- Isentropic Expansion
- Isentropic Heat Rejection
- Isentropic Compression
What are the Carnot Principles?
- The efficiency of an irreversible heat engine is always less than the efficiency of a reversible one operating between the same two reservoirs
- The efficiencies of all reversible heat engines operating between the same two constant-temperature heat reservoirs have the same efficiency
What is the efficiency of a heat engine?
Net Work / Hot Heat Transfer
(Qh - Ql) / Qh
For a heat engine, how can we compare heat transfer and temperature?
Ql / Qh = Tl / Th
What is the Coefficient of Performance of a refrigerator?
Tl / (Th - Tl)
What is the Coefficient of Performance of a Heat Pump?
Th / (Th - Tl)
