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Unformatted text preview: MEAM 203 FALL 2002 THERMO - MIDTERM I Closed books. Write clearly! Explain all steps! GOOD LUCK. (50%) 1 . An ideal gas undergoes a cycle consisting of the following three processes: (i) Process 1-2: Isothermal compression from pressure p 1 =100kPa, temperature T1=300K, and the volume changes from volume V 1 =1.6m 3 to volume V 2 =0.2m 3 . (ii) Process 2-3: Constant pressure expansion from volume V 2 back to volume V 1 . (iii) Process 3-1: Constant volume process in which the gas pressure drops from p 3 to p 1 . The gas’ specific heat at constant volume Cv=0.7 kJ/kg-K and R=0.287 kJ/kg-K. (i) (10%) Depict all three processes on T vs V and p vs V diagrams. Mark along the curves the properties that are maintained fixed in each process. (ii) (10%) Determine the work and heat interactions during process 1-2. (iii) ( 5%) Determine the change of entropy during process 1-2. (iv) (10%) Determine the work and heat interactions during process 2-3. (v) (10%) Determine the change of entropy during process 2-3. (vi) ( 5%) Determine the change of entropy during process 3-1. (30%) 2 . One kilogram of superheated water at 500C and one kilogram of saturated vapor, both at 200kPa, are mixed in an adiabatic, constant pressure process. Determine: (i) (10%) The final temperature. (ii) (10%) The entropy generation during this process. (iii) (10%) The work interaction. Saturated Steam Table P (kPa) T (C) v v (m3/kg) u v (kJ/kg) h v (kJ/kg) s v (kJ/kg-K) 200 120 0.886 2530 2707 7.13 Superheated Steam Table (p=200kPa) T(C) v v (m3/kg) u v (kJ/kg) h v (kJ/kg) s v (kJ/kg-K) 300 1.32 2809 3097 7.90 400 1.55 2967...
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