Soln_Fall2008_HW7

# Soln_Fall2008_HW7 - State2: T2 = 50 4.7718 kJ/kg-K P2 =...

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SOLUTIONS –HW7 1. B.1.1, = (195+273.15)*4.1863= 1960kJ/Kg Table B.1.2 64.97 [273+(-10)]/[15-(-10)] = 10.52 1/10.52 = 0.095kJ 1-(273+64.97)/(273+195) = 0.278 0.095/0.278 = 0.34kJ 2.

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, State 1: u1 = 1379 kJ/kg, s1 = 5.3171 kJ/kg-K State 2: u2 = 1409.8 kJ/kg, s2 = 6.7703 kJ/kg-K, v2 = 3.0447 m3/kg, h2 = 1562 kJ/kg 1Q2 = mT(s2-s1) = 1*(273+40)*(6.7703-5.3171) = 454.85 kJ. 1W2 = 1Q2 – m(u2-u1) = 454.85 – 1*(1409.8-1379) = 424.05 kJ 3. 0.008/4 = 0.002 m3/kg x1 = (v1-vf)/vfg = (0.002-0.001002)/57.7887 = 1.73e-5 u1 = uf + x1*ufg = 83.94 + 1.73e-5*2318.98 = 83.98 kJ/kg s1 = sf + x1*sfg = 0.2966 + 1.73e-5*8.3706 = 0.2967 kJ/kg-K x2 = (0.002-0.001114)/0.24171 = 0.00367 u2 = 718.31 + 0.00367*1858.14 = 725.13 kJ/kg s2 = 2.0418 + 0.00357*4.6244 = 2.0583 kJ/kg-K 4*(725.13-83.98) = 2564.6 kJ 4*(2.0583-0.2967) = 7.0464 kJ/K
4. State 1: T1 = 10 x1 = 0.9, V1 = 150L = 0.15 m3 615.2 kPa. 0.0016 + 0.9*0.20381 = 0.1850 m3/kg 225.99 + 0.9*1099.7 = 1215.72 kJ/kg 0.8779 + 0.9*4.3266 = 4.7718 kJ/kg-K 0.15/0.1850 = 0.8108 kg

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Unformatted text preview: State2: T2 = 50 4.7718 kJ/kg-K P2 = 2000 kPa, u2 = 1344.5 kJ/kg 0.8108*(1215.72-1344.5) = -104.41 kJ 5. v1 = 0.10539 m3/kg, u1 = 1476.3 kJ/kg, s1 = 5.3659 kJ/kg-K m = V1/v1 = 0.2/0.10539 = 1.8977 kg P2 = 1003.2 kPa v2 = 0.001658 + 0.15*0.12647 = 0.0206 m3/kg, u2= 296.59 + 0.15*1038.4 = 452.35 kJ/kg s2 = 1.1210 + 0.15*3.9083 = 1.7072 kJ/kg-k = 1/2*1.8977*(1600+1003.2)*(0.0206-0.10539) = -209.44 kJ . = 1.8977*(452.35-1476.3) + (-209.44) = -2152.59 kJ = 1.8977*(1.7072-5.3659) (-2152.59/(273+25)) = 0.2803 kJ/kg-K 6. State 1: T1 = 800 , P1 = 8000 kPa, V1 = 200L = 0.2 m3, Table B.1.3 v1 = 0.06097 m3/kg, m = m1 = V1/v1 = 0.2/0.06097 = 3.2803 kg h1 = 4123.84 kJ/kg-K s1 = 7.5173 kJ/kg State 3: P3 = P1 = 8000kPa, x3 = 0, Table B.1.2 h3 = hf = 1316.61 kJ/kg, s3 = sf = 3.2067 kJ/kg-K = 3.2803*(1316.61-4123.84) = -9208.56 kJ 9209 kJ 25 (273+25)* 3.2803*(3.2067-7.5173) = -4214 kJ 4214 kJ 9209 4214 = 4995 kJ ....
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## This note was uploaded on 09/29/2009 for the course ME 530.230 taught by Professor Katz during the Spring '09 term at Johns Hopkins.

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Soln_Fall2008_HW7 - State2: T2 = 50 4.7718 kJ/kg-K P2 =...

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