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| 1 | |
Steam at 1 mPa, 300°C flows through a 30 cm diameter pipe with an average velocity of 10 m/s. The mass flow rate of this steam is: |
| | A) | 0.731 kg/s |
| | B) | 2.74 kg/s |
| | C) | 3.18 kg/s |
| | D) | 3.78 kg/s |
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| 2 | |
Refrigerant-134a flows through a pipe at 800 kPa, 50°C. The specific flow work required to move this fluid through a cross-section of the pipe is: |
| | A) | 22.77 kJ/kg |
| | B) | 31.60 kJ/kg |
| | C) | 37.21 kJ/kg |
| | D) | 40.70 kJ/kg |
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| 3 | |
A mixture of ideal gases has an apparent molecular weight of 36.4 kg/kg-mole and a specific enthalpy of 273.2 kJ/kg when the temperature is 127°C. The specific internal energy of this gas mixture is: |
| | A) | 98.72 kJ/kg |
| | B) | 153.1 kJ/kg |
| | C) | 181.8 kJ/kg |
| | D) | 273.2 kJ/kg |
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| 4 | |
Air enters an adiabatic, steady-flow turbine at 1 MPa, 527°C through a 1 m2 duct with a velocity of 100 m/s. The air leaves the turbine at 100 kPa, 157°C. The mass flow rate of the air is: |
| | A) | 87.4 kg/s |
| | B) | 137.3 kg/s |
| | C) | 327.2 kg/s |
| | D) | 435.6 kg/s |
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| 5 | |
Air enters an adiabatic, steady-flow turbine at 1 MPa, 527°C throuigh a 1 m2 duct with a velocity of 100 m/s. The air leaves this turbine at 100kPa, 157°C. The work produced by this turbine based upon temperature variable specific heats is: |
| | A) | 293.2 kJ/kg |
| | B) | 360.3 kJ/kg |
| | C) | 390.5 kJ/kg |
| | D) | 420.6 kJ/kg |
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| 6 | |
Steam at 4 MPa, 400°C enters a steady-flow, adiabatic turbine through a 20 cm-diameter-pipe with a velocity of 20 m/s. It leaves this turbine at 50 kPa with a quality of 80% through a 1 m-diameter pipe. What is the velocity of the steam as it leaves the turbine? |
| | A) | 10.3 m/s |
| | B) | 28.2 m/s |
| | C) | 32.6 m/s |
| | D) | 73.3 m/s |
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| 7 | |
Saturated liquid water enters an adiatic steady-flow throttle valve at 500 kPa and leaves at 100 kPa. What is the quality of the water liquid-vapor mixture leaving this valve? |
| | A) | 9.87% |
| | B) | 10.6% |
| | C) | 14.3% |
| | D) | 21.1% |
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| 8 | |
Air enters the afterburner nozzle of a jet fighter at 427°C with a velocity of 100 m/s. It leaves this adiabatic nozzle at 377°C. Assuming that the air specific heats do not change with temperature, the velocity at the nozzle exit is: |
| | A) | 142 m/s |
| | B) | 178 m/s |
| | C) | 227 m/s |
| | D) | 343 m/s |
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| 9 | |
Air is compressed from 100 kPa, 300 K to 500 kPa, 500 K in an adiabatic, steady-flow compressor. Allowing for variations in the air's specific heat with temperature, the work required for this compression is: |
| | A) | 132 kJ/kg |
| | B) | 186 kJ/kg |
| | C) | 203 kJ/kg |
| | D) | 241 kJ/kg |
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| 10 | |
An initially empty, rigid, insulated container is filled with air from a constant pressure, Pl, and temperature, Tl, supply line. When filled, the air pressure in the vessel matches that in the line. The final temperature of the air in the vessel is given by which of the following equations? |
| | A) | Tf = cvTl / cp |
| | B) | Tf = cpTl / cv |
| | C) | Tf = Tl |
| | D) | Tf = RTl / cv |
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