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Heat engines convert thermal energy into...
mechanical work
how many properties do we need to solve for something in thermodynamics?
2
What cycles has:
- 2 isentropic process
- 2 constant pressure process
- is an ideal gas
Brayton Cycle
What will happen to the entropy of a substance as it freezes.
it will decrease in entropy
The first law of thermodynamics is a restatement of what law?
the law of conservation of energy
what is the fastest naturally aspirated car?
McLaren F1
which property is only between the values of 1 and 0.
quality
What 2 Isothermal cycles known for their use in external combustion engines?
The Stirling and Ericsson cycles
when is a process determined as reversible?
When the efficiency of the process equals the maximum efficiency.
What thermodynamic process in which no heat is exchanged with the surroundings, and the internal energy remains constant?
Adiabatic process.
In a turbojet engine, what is the primary purpose of the component known as the "afterburner"?
To provide an additional thrust boost by injecting and burning fuel in the exhaust stream, increasing the velocity of the exhaust gases.
Name two intensive properties.
color, density, temperature, odor, melting/boiling point, rusting, luster.. any property that is independent on mass.
In which power cycle do most traditional car engines operate, involving constant volume heat addition and rejection?
The Otto cycle
find entropy generation:
s1= 3.7252kJ/kg-K
s2=4.1347kJ/kg-K T= 143.76C
Q=161.3 kj/kg
ans: 0.02247 kJ/kg-K
If a closed system undergoes a thermodynamic process and its internal energy remains constant, what can be said about the heat and work interactions?
Q = -W, meaning the heat added is equal to the work done by the system.
what does MEP stand for and how do you find it?
Mean effective pressure is defined as the Eaverage pressure needed to act on the piston as it moves one displacement in order to produce work W.
MEP= W/v2-v1
what is the value of R (not the universal one) for air
0.287 J/g-K
What power cycle is often employed in large-scale power plants, utilizing compression and expansion processes with constant pressure heat addition and rejection?
The Rankine cycle.
true or false:
Heat will always flow from cold to hot
False
In the context of the First Law of Thermodynamics, what is the term for the work done by a system when the volume change is not against an external pressure, but rather against an opposing force?
Piston work or shaft work.
what are the names or your PLTL leaders?
Ornoba and Mouzen
convert 20 m2/s2 to kj/kg
0.02
In which reversible thermodynamic cycle is the refrigeration process commonly used, involving the absorption of heat from a low-temperature reservoir?
The Reverse Carnot cycle.
determine the thermal efficiency of this process:
Qin = 80MW
Qout= 50M\
ans: 37.5%
true or false??
Entropy is the amount of order and organization in a system
false