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Unformatted text preview: SOLUTIONS SAMPLE 1 MAE 301: Engineering Thermodynamics I Spring 2010 Test 1 (15% of final grade) February 16, 2010 Closed books & notes Problem 1. (25 points) A fan driven by an electrical motor is to accelerate quiescent air to a velocity of 10 m/s. The mass flow rate of air is 5 kg/s. The combined efficiency of the fan-motor assembly is 80 %. Determine the electric power that must be supplied to the motor. Solution: The total power required to accelerate air: W v m W 250 5 . 100 5 2 2 fluid = = = & & The electric power required: W W W electric 5 . 312 8 . 250 fluid = = = & & Problem 2. (25 points) In a hydroelectric power plant, 100 m 3 /s of water flows from an elevation of 70 m to a turbine-generator assembly, where electric power is generated. The efficiency of turbine is 90%, and efficiency of generator is 95%. Determine the energy losses in water piping if 50 MW of electrical power output is produced....
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This note was uploaded on 05/19/2010 for the course MAE 301 taught by Professor Hassan during the Spring '08 term at N.C. State.
- Spring '08