Introduction To Thermodynamics - Final Exam | CHE 201, Exams of Thermodynamics

Download Introduction To Thermodynamics - Final Exam | CHE 201 and more Exams Thermodynamics in PDF only on Docsity! Name: ChE 201: Intro to Thermodynamics Final Exam Show all work! State all assumptions! Get everything right! Problem 1: Problem 2: Problem 3: Problem 4: Problem 5: 25 pts 25 pts 35 pts 35 pts 30 pts Problem 6:50 pts Total: 200 pts total: Fall 2005 Wednesday, December 7 Problem 1. (25 pts) A 3000 1b,, car at the top of a 100 m hill initially traveling at 50 miles/hr will come to rest on the level street below as the brakes are applied. The four wheel disc brakes have a total mass of 40 Ib, and are made of a metal with a heat capacity of 0.2 Bto/Ib,R. If the car and brakes are initially at 80°F, what will the final temperature of the brakes be? Problem 3. (35 pts) Air data: Cp = 1.09 kJ/kg, Cy = 0.800 ki/kgk Figure P6.91 provides steady-state operating data for a well-insulated device with air enlering at one Jocation and ex- iting at auother with a mass flow rate of 10 kg/s, Assuming ideal gas behavior and negligible potential energy effects, de~ termine the direction of flow and the power, in kW. Problem 4. (35 pts) a) Compute the minimum amount of power required by an adiabatic compressor that handles 10 lby,/min of Freon 12, compressing it from -20°F, 10 psia to 300 psia. b) What will the entropy production rate be if the compressor efficiency is 80%? FIG. B-7 Thermadynamie prop- Constant erties of freon-12, Courtesy af the ae EL. dit Pont de Nemours Com- 30 pany. T in °F,» in fi/thm, # in Btu/lom-°R, quality in percent i, Pressure, psia -20 0 -200CO4sisisis—“(i CSCO ED 170180150 Seale change—phe— ones Enthaipy, Stu/lhm above saturated Ilquid at —40°  TABLE A-2E Properties of Saturated Water (iquid--Vapor): Temperature Table Specific Volume Internal Energy Enthalpy Entropy fb Bra/tb Rtv/lb Beu/Ib-°R Sat. Sat. Sat. Sat. Sat. Sat Sat. Temp. | Press. | Liquid | Vapor | Liquid | Vapor | Lignid | Evap. | Vapor | Liquid | Ibffin? uy on Me % hy hig hy 5 3308 [vor 24 4) = .0p00 gb48 “4100.3 0.00607: f.1023,9- fs, 0.01617. 1025571, 002618 1027.2. 0.03607, - 52] 0.1917 | 0.01603 | 1589 1027.8 0.04000 54 | 0.2064 | @.o1603 | 1482 1028.5 0.04391 56} 0.2219 } o.01603 | 1383 1029.1 0.04781 58 | 0.23K6 | o.01603 | 1292 1029.8 0.05159 | 2.1605 1207 1030.4 0.05555 | 2.0943 60 0.2563 0.01604 72 0.3887 0.01606 we 0.4158 | 0.01606 i) 0.4446 1 0.01606 8 0.4750 | 0.01607 80 0.5073 | 0.01607 1033: 40.09 10344 40.09 42.09 1035.0 42.09 44.09 1035.7 44.09 46.09 | 1036.3 46.09 48.08 | 1037.0 48.09 10,1007: 03 007463 0.07839 0.08215 0.08589 0.08961 0.09332 0.09704, 4. 1080; ee f 92 O.0161E | 4409 | 60.06 0.1183 | 2.0030 92 94 0.01611 415.9 62.06 0.1189 1.9977 94 96 0.01612 3924 64.05 0.1225 1.9925 | 96 98 G.01612 | 3705 | 66.05 0.1261 1.9874 98 100 0.01613 | 350.0} 68.04 0.1296 1.9822 | 100 Specific Volume Tnternal Energy Enmthalpy Entropy fb Bu/lb Buu/lb Bu/lb-°R Sat. Sat. Sat, Sat, Sat, Sat. Sat. Sat. Temp. Press, Liquid Vapor Liquid Vapor | Liquid | Evap. Vapor Liquid Vapor | Temp. °F ibffin? uy Dy Up ty by deg A, Se 5p - mOE) i 8D as 250 29.82 | 0.01700 | 13.83 2185 | 1087.9 | 218.6 | 945.6 | 11642 | 0.3677 | 1.7001 | 250 260 35.42 | 0.01708 | 11.77 228.6 1090.5 228.8 938.8 1167.6 | 0.3819 | 16864 | 260 270 41.85 | 0.01717 | 10.07 238.8 | 1093.0 | 239.0 | 9326 1 1170.9 | 0.3960 | 1.6731 | 270 280 49.18 | 0.01726 | 8.65 249.0 | 1095.4 | 249.2 | 9249 | 11741 | 0.4099 | 15602 | 286 290 57.53 | 0.01735 | 7.47 259.3 | 1097.7 | 2594 | 9178 | 1177.2 | 0.4236 | 1.6477 | 299