Thermodynamics: A Smart Approach 1st. Edition by Ibrahim Dincer | 9781119387879 | 1119387876 | Holooly

Thermodynamics: A Smart Approach

142 SOLVED PROBLEMS

Question: 5.13

Air compressor, as shown in Figure 5.15, takes in air at atmospheric pressure and at a temperature of 280 K, and the air exiting the compressor leaves at a pressure and a temperature of 600 kPa and 400 K. The air mass flow rate of the air being compressed is 1 kg/s; the compressor loses heat ...

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One may start with some assumptions: (i) the heat ...

Question: 5.6

Consider a piston–cylinder device, as shown in Figure 5.8, which initially contains air at a pressure of 400 kPa and a temperature of 17 °C. The air in the piston–cylinder device receives 50 kJ of work per each kg of air in the device through the rotating paddle. The air in the device receives ...

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a) Write the mass, energy, entropy, and exergy bal...

Question: 5.7

A balloon with a 12 kg of refrigerant R134a in the saturated vapor state at a pressure of 240 kPa, as shown in Figure 5.9, is expanded in a process, during which a total of 300 kJ of heat is transferred to the refrigerant. Take the source temperature of heat as 300 ºC. (a) Write the mass, ...

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a) Write the mass, energy, entropy, and exergy bal...

Question: 5.8

Hot water at a temperature of 95 °C and a pressure of 100 kPa flows in a pipe at a flow rate of 1 kg/s, as shown in Figure 5.10. The pipe loses heat at a rate of 1 kW per meter along the pipe length. (a) Write the mass, energy, entropy, and exergy balance equations, (b) find the temperature ...

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a) Write the mass, energy, entropy, and exergy bal...

Question: 5.9

Consider a diffuser as shown in Figure 5.11a with inlet and exit pressures of 90 and 94 kPa, respectively. The inlet air temperature, the entrance area and the inlet air velocity are 10 °C, 6.4 m2 and 94 m/s. Treat air as an ideal gas and use its properties. (a) Write the mass, energy, entropy ...

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Solution for the Diffuser a) Write the balance equ...

Question: 5.10

Consider an adiabatic steam turbine, as shown in Figure 5.12, which receives 10 kg/s of superheated steam at a temperature of 500 °C and a pressure of 10 000 kPa. The steam turbine converts part of the energy in the steam to the shaft work output. The steam exits the steam turbine as a saturated ...

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a) Write the mass, energy, entropy, and exergy bal...

Question: 5.12

The hot exhaust gases leaving an internal combustion engine at 400 C, 150 kPa, and at a rate of 0.8 kg/s are used to produce saturated steam at 200 C in an insulated heat exchanger, as shown in Figure 5.14. Water enters the heat exchanger at the ambient temperature of 20 C and the exhaust gases ...

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a) Write the mass, energy, entropy, and exergy bal...

Question: 5.14

An electric motor–pump unit, as shown in Figure 5.16, is used to raise the pressure of water from ambient conditions to a pressure of 900 kPa and a temperature of 30 °C. The water entering the pump is at a temperature of 25 °C, at atmospheric pressure, and the mass flow rate is 0.5 kg/s.(a) Write ...

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a) Write the mass, energy, entropy, and exergy bal...

Question: 5.15

In a vapor-compression refrigeration cycle, consider refrigerant R134a at a pressure of 0.8 MPa and in the saturated liquid state flowing through an expansion valve, as shown in Figure 5.17. The refrigerant is then throttled down to a pressure of 0.12 MPa. (a) Write the mass, energy, entropy, ...

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a) Write the mass, energy, entropy, and exergy bal...

Question: 5.16

Propane enters a heat exchanger, as shown in Figure 5.18, at 4 °C at a mass flow rate of 32.6 kg/s to be heated with exhaust gases for later use at a constant pressure of 1 MPa. The exhaust gases flow at a rate of 2.484 × 10^5 kg/h and a temperature of 400 °C. Treat both propane and exhaust gases ...

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a) Write mass, energy, entropy, and exergy balance...

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