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2 and 2 3. During the 7. A pure ,the temperature increases linearly with entropy. The...
An aircraft engine operates on a simple ideal Brayton cycle with a pressure ratio rp of...
An aircraft engine operates on a simple ideal Brayton cycle with
a pressure ratio rp of 9. Heat is added to the cycle at a rate of
490 kW; air passes through the engine at a rate of 1.1 kg/s; and
the air at the beginning of the compression is at P1 = 71 kPa and
T1 = 0 oC. Use constant specific heats at room temperature. The
properties of air at room temperature are cp =1.005 kJ/kg.K and k...
Problem 4 – Entropy transfer in a control volume (18 pts) An adiabatic reversible steam turbine...
Problem 4 – Entropy transfer in a control volume (18 pts) An
adiabatic reversible steam turbine steadily processes 2 kg/s of
steam at 5 MPa and 450°C, which is exhausted at 100 kPa and 100°C.
The turbine exhibits an isentropic efficiency of 0.85. a) Draw a
schematic representation of the system with all the energy
interactions involved. (2pts) b) Determine the h (kJ/kg) and s
(kJ/kg-K) at the inlet. (2 pts) c) Determine the actual h (kJ/kg)
and s (kJ/kg-K)...
For all of the processes, you may assume the gases have the properties of pure air...
For all of the processes, you may assume the gases have the properties of pure air and are thermally and calorically perfect. For all processes except the exhaust nozzle, you may neglect kinetic and potential energy changes. Therefore, the static and stagnation properties are equal. 50 kg/s of air enters an adiabatic compressor at 1 atm and 300 K and compresses the air to 30 atm. The compressor has an adiabatic efficiency of 90%. The compressor adiabatic efficiency is W...
1. (42 points) A piston-cylinder device contains 6 kg of steam at 100°C with a quality...
1. (42 points) A piston-cylinder device contains 6 kg of steam at 100°C with a quality of 50 percent. This steam undergoes two processes as follows: 1-2 Heat is transferred to the steam in a reversible manner while the temperature is held constant until the steam exists as a saturated vapor. 2-3 The steam expands in an adiabatic, reversible process until the pressure is 15 kPa. (a) (24 points) Fill in the table using the given and determined properties. You...
3. Consider a gas with the properties of air. The gas begins at a state described...
3. Consider a gas with the properties of air. The gas begins at a state described by a pressure of I5 atm and 600 K. If the gas is taken to a new state in which the temperature is 400 K and the pressure is 1 atm, determine the entropy change in two ways: 1. use an isentropic expansion from the first state down to a pressure of 1 atm and then reversible heating from the resulting temperature to the...
True or False (Problems 1 through 10) 1. The change in entropy of a closed system...
True or False (Problems 1 through 10) 1. The change in entropy of a closed system is the same for every process between two specified states 2. The entropy of a fixed amount of an incompressible substance increases in every process for which temperature increases 3. A process that violates the second law of thermodynamics violates the first law of thermodynamics. 4. When a net amount of work is done on a closed system undergoing an internally reversible process, a...
PROBLEM-3 (30%) One kg of air in a piston-cylinder assembly undergoes two processes in series from...
PROBLEM-3 (30%) One kg of air in a piston-cylinder assembly undergoes two processes in series from an initial state where P1 = 0.5 MPa, T1 = 227°C: Process 1-2: Constant-temperature expansion until the volume is twice the initial volume. Process 2–3: Constant-volume heating until the pressure is again 0.5 MPa. Sketch the two processes in series on a P-v diagram. Assuming ideal gas behavior, determine: (a) the pressure at state 2, (in MPa) (b) the temperature at state 3, (in...
(25 pts) A well-insulated and well-sealed 2-m x 3-m x 4-m room is initially at Tal...
(25 pts) A well-insulated and well-sealed 2-m x 3-m x 4-m room is initially at Tal = 22 °C and p = 100 kPa. A mass of mw = 20 kg of liquid water at Tw./ = 80 °C is brought into the room and the system is allowed to reach equilibrium conditions (state 2). 2m x 3m x 4m ROOM 22°C 100 kPa Specific heat values for the air and water may be taken as Cp,air = 1.005 kJ/kg-K;...
1) Identify whether entropy increases, decreases, or remains unchanged during each of the following processes. a)...
1) Identify whether entropy increases, decreases, or remains unchanged during each of the following processes. a) Freezing liquid water b) Dissolving sodium chloride crystals into liquid water c) Expanding argon gas isothermally from 2 bar to 1 bar d) Chilling a steel ball bearing from 100 C to 25 oC e) Crystallizing a protein from an aqueous solution _- f) Heat shrink tubing shrinks (2) For each of the following processes predict qualitatively the sign for the change in entropy...
Problem 2: (10 pts) A 30-kg iron block at initial temperature 200°C and a 40-kg copper...
Problem 2: (10 pts) A 30-kg iron block at initial temperature 200°C and a 40-kg copper block at initial temperature 100°C are dropped into a very large lake at 20°C. Thermal equilibrium is established after a while as a result of heat transfer between the blocks and lake water. Both blocks have constant specific heats, i.e. Ciron = 0.45 kJ/kg. K and Ccopper = 0.386 kJ/kg. K. Hint: The very large lake can be treated as a heat reservoir and...
An aircraft engine operates on a simple ideal Brayton cycle with
a pressure ratio rp of 9. Heat is added to the cycle at a rate of
490 kW; air passes through the engine at a rate of 1.1 kg/s; and
the air at the beginning of the compression is at P1 = 71 kPa and
T1 = 0 oC. Use constant specific heats at room temperature. The
properties of air at room temperature are cp =1.005 kJ/kg.K and k...
Problem 4 – Entropy transfer in a control volume (18 pts) An
adiabatic reversible steam turbine steadily processes 2 kg/s of
steam at 5 MPa and 450°C, which is exhausted at 100 kPa and 100°C.
The turbine exhibits an isentropic efficiency of 0.85. a) Draw a
schematic representation of the system with all the energy
interactions involved. (2pts) b) Determine the h (kJ/kg) and s
(kJ/kg-K) at the inlet. (2 pts) c) Determine the actual h (kJ/kg)
and s (kJ/kg-K)...
For all of the processes, you may assume the gases have the properties of pure air and are thermally and calorically perfect. For all processes except the exhaust nozzle, you may neglect kinetic and potential energy changes. Therefore, the static and stagnation properties are equal. 50 kg/s of air enters an adiabatic compressor at 1 atm and 300 K and compresses the air to 30 atm. The compressor has an adiabatic efficiency of 90%. The compressor adiabatic efficiency is W...
1. (42 points) A piston-cylinder device contains 6 kg of steam at 100°C with a quality of 50 percent. This steam undergoes two processes as follows: 1-2 Heat is transferred to the steam in a reversible manner while the temperature is held constant until the steam exists as a saturated vapor. 2-3 The steam expands in an adiabatic, reversible process until the pressure is 15 kPa. (a) (24 points) Fill in the table using the given and determined properties. You...
3. Consider a gas with the properties of air. The gas begins at a state described by a pressure of I5 atm and 600 K. If the gas is taken to a new state in which the temperature is 400 K and the pressure is 1 atm, determine the entropy change in two ways: 1. use an isentropic expansion from the first state down to a pressure of 1 atm and then reversible heating from the resulting temperature to the...
True or False (Problems 1 through 10) 1. The change in entropy of a closed system is the same for every process between two specified states 2. The entropy of a fixed amount of an incompressible substance increases in every process for which temperature increases 3. A process that violates the second law of thermodynamics violates the first law of thermodynamics. 4. When a net amount of work is done on a closed system undergoing an internally reversible process, a...
PROBLEM-3 (30%) One kg of air in a piston-cylinder assembly undergoes two processes in series from an initial state where P1 = 0.5 MPa, T1 = 227°C: Process 1-2: Constant-temperature expansion until the volume is twice the initial volume. Process 2–3: Constant-volume heating until the pressure is again 0.5 MPa. Sketch the two processes in series on a P-v diagram. Assuming ideal gas behavior, determine: (a) the pressure at state 2, (in MPa) (b) the temperature at state 3, (in...
(25 pts) A well-insulated and well-sealed 2-m x 3-m x 4-m room is initially at Tal = 22 °C and p = 100 kPa. A mass of mw = 20 kg of liquid water at Tw./ = 80 °C is brought into the room and the system is allowed to reach equilibrium conditions (state 2). 2m x 3m x 4m ROOM 22°C 100 kPa Specific heat values for the air and water may be taken as Cp,air = 1.005 kJ/kg-K;...
1) Identify whether entropy increases, decreases, or remains unchanged during each of the following processes. a) Freezing liquid water b) Dissolving sodium chloride crystals into liquid water c) Expanding argon gas isothermally from 2 bar to 1 bar d) Chilling a steel ball bearing from 100 C to 25 oC e) Crystallizing a protein from an aqueous solution _- f) Heat shrink tubing shrinks (2) For each of the following processes predict qualitatively the sign for the change in entropy...
Problem 2: (10 pts) A 30-kg iron block at initial temperature 200°C and a 40-kg copper block at initial temperature 100°C are dropped into a very large lake at 20°C. Thermal equilibrium is established after a while as a result of heat transfer between the blocks and lake water. Both blocks have constant specific heats, i.e. Ciron = 0.45 kJ/kg. K and Ccopper = 0.386 kJ/kg. K. Hint: The very large lake can be treated as a heat reservoir and...
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