Thermo Midterm 2088

Thermo Midterm 2088 - as the tank is heated to maintain a...

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psi F ft 3 /lbm Btu/lbm Btu/lbm p T v u h x (if app.) 1 80 2 20 3 1215.4 4 1102.6 ME-302 Thermodynamics Fall 2008 Midterm Name:_______________________________ Section: _______ 1. (25 points) Answer the following questions about the steady state system shown below. (Don’t worry about stating assumptions) a) Is it appropriate to use the ideal gas law for the air traveling through the heat exchanger [find Z]? b) Fill in the table of thermodynamic properties. c) Draw p- v and T- v diagrams in the indicated spaces. d) If we were to assume a polytropic process across the compressor, what is n and how much work is developed [in Btu/lbm]? e) What kind of cycle might this be and why? What is the cycle efficiency? 2. (15 points) A tank having a volume of .75 m 3 contains a liquid-vapor mixture of water. Initially, the temperature in the tank is 200°C and a quality of 0.6. Saturated water vapor at 200°C slowly escapes through a valve at the top of the tank
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Unformatted text preview: as the tank is heated to maintain a constant pressure in the tank. This continues until the tank is filled with saturated vapor. Determine the amount of heat transfer in kJ. Answer: Remember schematic, assumptions, p-v and T-v diagrams. 3. ( 10 points) A Japanese sword-smith is making a katana out of AISI 302 Steel. The 2 lb sword is nearly finished and is being tempered. After being heated to a temperature 900 F the sword-smith places the sword in a vat of oil to cool. The dimensions of the vat are 48 x 18 x 9 (assume the vat is full of oil). The equilibrium temperature of both the sword and the oil is 100 F. What was the initial temperature of the oil? Answer: Remember schematic and assumptions. (p-v and T-v diagrams are not necessary.)...
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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.

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