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Unformatted text preview: SAMPLE 1 MAE 301: Engineering Thermodynamics I Spring 2010 Test 2 (15% of final grade) March 11, 2010 Closed books & notes Problem 1. (25 points) A tank fitted with an electrical resistor of negligible mass holds 2 kg of nitrogen, initially at 27 C, 100 kPa. Over a period of 10 minutes, electricity is provided to the resistor at a rate of 0.12 kW. During the same period, a heat transfer of magnitude 12.59 kJ occurs from the nitrogen to its surroundings. Assuming ideal gas behavior, determine the nitrogen final temperature and pressure. Problem 2. (25 points) Saturated water vapor is contained in a closed rigid tank. The water is cooled to a temperature of 110 C. At this temperature the masses of saturated vapor and liquid are each 100 kg. Determine the heat transfer for the process, in kJ. Problem 3. (25 points) Refrigerant 134a enters an air conditioner compressor at 3.2 bar, 10 C, and is compressed at steady state to 10 bar, 70 C. The volumetric flow rate of refrigerant entering is 3.0 The volumetric flow rate of refrigerant entering is 3....
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