Assignment 1

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ASSIGNMENT 1

1. A rigid tank with a volume of 1.8 m3 contains 15 kg of saturated liquid vapor mixture of water at 90oC. Now the water is slowly heated. Determine the temperature at which the liquid in the tank is completely vaporized. Also, show the process on a T-v diagram with respect to saturation lines.
(5 marks)

2. A 0.5 m3 vessel contains 10 kg of refrigerant-134a at -20oC. Determine (a) the pressure, (b) the total internal energy, and (c) the volume occupied by the liquid phase.
(8 marks)

3. A tank whose volume is unknown is divided into two parts by a partition. One side of the tank contains 0.01 m3 of refrigerant-134a that is a saturated liquid at 0.8 MPa, while the other side is evacuated. The partition is now removed, and the refrigerant fills the entire tank. If the final state of the refrigerant is 20oC and 400 kPa, determine the volume of the tank.
(4 marks)

4. As shown in Figure 1, a 0.5 m3 rigid tank containing hydrogen at 20oC and 600 kPa is connected by a valve to another 0.5 m3 rigid tank that holds hydrogen at 30oC and 150 kPa. Now the valve is opened and the system is allowed to reach thermal equilibrium with the surroundings, which are at 15oC. Determine the final pressure in the tank.
(4 marks)

Figure 1 5. Nitrogen at 150 K has a specific volume of 0.041884 m3/kg. Determine the pressure of the nitrogen, using (a) the ideal gas equation and (b) the Beattie-Bridgeman equation. Compare your results to the experimental value of 1000 kPa.
(9 marks)

Date of submission: 19th October 2011 (EH2211A)/20th October 2011 (EH2201B)