Practice Problems for Test 1 - Thermodynamics | MAE 251, Exams of Thermodynamics

Download Practice Problems for Test 1 - Thermodynamics | MAE 251 and more Exams Thermodynamics in PDF only on Docsity! MAE251 Test 1 Spring 2009 Closed book – time: 50 min – grading: 10+10 1. A piston-cylinder device initially contains steam at 120 oC, 150 kPa and 0.5 m3. At this state, a linear spring is touching the piston but exerts no force on it. Heat is slowly transferred to the steam, causing the pressure and volume to rise to 300 kPa and 0.55 m3, respectively. Show the process on a p-v diagram, properly labeled. Determine the final temperature and the work and heat transferred during the process. (ignore the numbers on the figure!) 2. One kg of carbon monoxide (ideal gas) is compressed from 1 MPa and 200oC to 3MPa in a piston-cylinder device arranged to execute a polytropic process pV1.5 = constant. Determine the final temperature and the heat transfer. Conversion factors: 1 bar = 100 kPa 1 Btu = 778 lbf.ft 1 psi = 1 lbf/in2 gc = 32.2 lbm.ft/lbf.s2 K = oC + 273 oR = oF + 460 Table A-4 __ Properties of Superheated Water Vapor J & u h s v “ h 5 Cc om/kgKI/kg/kg— kg K mv/kg kikgki/kg—k/kg-K = 15 bar = 0.15 MPa p = 3.0 bar = 0.30 MPa (Fa, = 111.37°C) (Lou = 133.55°C) Sat. © 1.159 | 2519.7 | 2693.6 [7.2233 © 0,606 | 2543.6 | 27253 | 6.9919 WO 1.188 | 2533.3 | 27114 | 7.2693” See 160 --1.317 | 2595.2 | 2792.8. | 7.4665 0.651 | 2587.1} 2782.3 | 7.1276 1.444 | 2656.2 | 2872.9 | 7.6433 0.716 | 2650.7 | 2865.5 | 7.3115 1.570 | 2717.2 | 2952.7 | 7.8052 0.781 | 2713.1 | 2947.3 | 7.4774 1.695 | 2778.6 | 3032.8 | 7.9555 0.844 | 2775.4 | 3028.6 | 7.6299 1.819 | 2840.6 | 3113.5 | 8.0964" © 0.907 | 2838.1 | 311049] «7.7722 1,943 | 2903.5 | 3195.0 | 8.2293 0.969 | 2901.4 | 3192.2 | 7.9061 2.067 | 2967.3} 3277.4 | 8.3555 Be 1.032 | 2965.6 | 3275.0 | 8.0330. 2.191 | 3032.1 | 3360.7 | 8.4757 1.094 | 3030.6 | 3358.7 | 8.1538 500 2.376 | 3131.2 | 3487.6 | 8.6466 1.187 | 3130.0 | 3486.0 | 8.3251 600 3301.7 | 3704.3 | 8.9101 1.341 | 3300.8 | 3703.2 | 8.5892 Table A-20 _\deal Gas Specific Heats of Some Common @ eee |e & | & k Temp. K Air Nitrogen, Ny 250 | 1.003 | 0.716 | 1.401 | 1.039 | 0.742 | 1.400 300 | 1.005 | 0.718 | 1.400 | 1.039 | 0.743 | 1.400 350} L008 | 0.721 | 1.398 | 1.041 | 0.744 | 1.399 400 | 1.013 | 0.726 | 1.395 | 1.044 1,397 450 | 1.020 | 0.733 | 1.391 | 1.049 | 1.395 500 | 1.029 | 0.742 | 1.387 | 1.056 ) 1391 550 | 1.040 | 0.753 | 1381 | 1.065 | 1.387 { 600 | 1.051 | 0.764 | 1.376 | 1.075 650. | 1.063 | 0.776 | 1.370 | 1.086 | 700 | 1.075 | 0,788 | 1.364 | 1.098 | oor | 1.371 750 | 1.087 | 0.800 | 1.359 | 1.110 | 0.813 800 | 1.099 | 0.812 | 1.354 | 1.121 | 0.825 900 | 1.121 } 0.834 | 1.344 | 1.145 | 0.849 | 1349 1000 | 1.142 | 0.855 | 1.336 | 1.167 | 0.870 | 1341 Temp. Carbon Carbon K Dioxide, CO, Monoxide, CO “250 | 0.791 | 0.602 300. | 0.846 | 0.657 350 | 0.895 | 0.706 Zz 1.039 | 0.743 | 1.400 1.040 | 0.744 | 1.399 1.043 | 0,746 | 1.398 400 | 0.939 | 0.750 450 | 0.978 | 0.790 500 | 1.014 | 0.825 1.047 | 0,751 | 1.395 1.084 | 0.757 | 1.392 1.063 | 0.767 | 1.387 550 | 1.046 | 0.857 | 1.220 | 1.075 | 0.778 | 1.382 600 | 1.075 | 0.886 | 1.213 | 1.087 | 0.790 | 1.376 650 | 1.102 | 0.913 | 1.207 | 1.100 | 0.803 | 1.370 700 | 1.126 | 0.937 | 1.202 | 1.113 | 0.816 | 1.364 150 | 1.148 | 0.959 | 1.197 | 1.126 | 0.829 | 1.358 800 | 1.169 | 0.980 | 1.193 | 1.139 | 0.842 | 1.353 900 | 1.204 | 1.015 | 1,186 | 1.163 | 0.866 | 1.343 1000. | 1.234 | 1.045 | L181 } 1.185 | 0.888 | 1.335 Source: Adanted from K. Wark. Thermodynamics, 4th ed.. McGraw-Hill