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Unformatted text preview: ME-302 Thermodynamics Midterm Spring 2008 Keller Name:____________________________ Section:_______ Question 1: .25 slug of water flows through a Carnot cycle. During the isothermal expansion process, the water is heated at 625 F from a saturated liquid to a saturated vapor. The vapor then expands adiabatically to a pressure of 6 psi with a quality of 64.3%. Fill in the charts below and sketch the process on a P-v diagram. Process 12 23 34 41 Cycle Q W State 1 2 3 4 Internal Energy (u) [BTU/lb] Entahlpy (h) [BTU/lb] Thermal Efficiency of the Cycle: Label the diagram with process lines, state numbers, Qc, Qh, Tc, Th, Win, Wout, and component names. ME-302 Thermodynamics Midterm Spring 2008 Keller Name:____________________________ Section:_______ Work from Question 1: ME-302 Thermodynamics Midterm Spring 2008 Keller Name:____________________________ Section:_______ Question 2: A household refrigerator that has a power input of 80 W (assume constant work input over time) and a coefficient of performance of 2.5 is to cool 24 bottles of Mt. Dew weighing 1 lb ea to 40 F. If the bottles are initially at 75 F, determine how long it will take for the refrigerator to cool them. Assume the cans can be treated as a pure substance whose specific heat is .42 Btu/lb F. Remember to draw a good schematic! Bonus Questions: 1) How long would it take an ideal fridge to cool these drinks? 2) Where was Lord Kelvin Baron? ...
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This note was uploaded on 08/27/2009 for the course ME 302 taught by Professor Staff during the Spring '06 term at Cal Poly.
- Spring '06