Midterm 2 Flashcards
True or false
Since the coefficient of performance measures efficiency, it cannot be greater than 1.
False
True or False
Heat engines operate on a cycle so that the total energy change in the system is always equal to zero.
True
Unsteady or non steady flow is one where the properties in the control volume depend on _______(Temp, pressure,time,volume,speed)?
Time
True or False
Regardless of the property of the fluid, under one inlet, one outlet, and steady state conditions, the volume flow rate of the inlet has to be the same as the volume flow rate of the exit.
False
True or False
Internal energy and enthalpy of an ideal gas are properties that only change with temperature and can be calculated by specific heat.
True
Moving boundaries work is often encountered in analyzing closed systems. For the energy balance equation analysis, expansion work is considered_______(positive or negative) and compression work is considered______.(positive or negative)
Positive, negative
True or False
The second law of Thermodynamics defines the direction of energy flow under natural conditions.
True
True or False
Heat engines operate on a cycle so that the total energy changes in the system is always equal to zero.
True
True or False
It is possible for an actual heat engine to reach efficiency of 100% if the engine is designed well.
False
True or False
Since the coefficient of performance measures efficiency it cannot be greater than 1
False
To find the enthalpy of a subcooled liquid at T or P one should look for a saturated liquid property at the same _________(Temp or pressure) state in the table
Temperature
Carnot Principle
1)The efficiency of an irreversible heat engine is always less than the efficiency of a reversible one operating between the same two reservoirs.
2) the efficiencies of all reversible heat engines operating between the same two resubmits are the same
What are thermal energy reservoirs?
Systems that have large masses and high heat capacities.
True or False
Flow work is the same as flow energy
True
True or False
Heat engine operates on a cycle and is converting heat to generate work m.
True
