Question

Find the thermal efficiency of the cycle and fill in the table for the values of the properties and the phase of the state. 1. Consider a steam power plant operating on the ideal Rankine cycle. Determine the thermal efficiency of this cycle. Boiler 13 4 MPa 450 °C Pump Turbine 7.5 kPa 04 Condenser Condenser State Phase Known Properties Unknown Properties

Answer 1

4 MPa 450°C 7.5 kPa. Conden gey AQP X W = Work done by turbine Wp = Work done by pump QA = Heat addition at const pressure in boilet RA - Heat rejected at const presudee in condenser P₂ = 4 MPa T3 = 450°C , p=1.5 -7.5x10,5 bar x 103 bar. 57.5X10 2 bar = 0.075 bar

@P, = 0.075 bar from steam tables. NP = 0.001008 m3/kg hic hp = 168.8 kJ/kg he hq = Wp he-h, = V4CB-P.) ha = Vp (B3-P.)+hi 30.001008 (4000–7.5) + 168.8 hy = 172.82 kJ/kg. @P2 = 40 bar from steam tables hyang = 2800.3 kJ/kg. Syzsg=6.069 Kolkg. but &z=4 =) 6.069 Kalkg. 54 = stle, tx за 10 6.069 = 0.516+ x (4-676) oo x = 0.7 156.

A ha = help + hog/p1 x x hac 16g. 9 + .11% (2406. 2) h4 = 1890.67672 kJ/kg. Trankine - Wy - We = (haha) -Cha-hi) . hy-ha = (890-67672 – 2800.3) - (172.32-168-8) (9808.3=117283) (1800-3-1890.6 7)-(172:82–1688) (1800.3-172-82) > 0.3446 12 - 34% Unknown State Phase I known saturated hi=168-8 kJ/kg kg / Temperature. water Pi= 7.5 kPa (Low pressure) extul SF 0.576 kalkg 2 Water High pressure low temp. he= 179-82 Koko P3 = 4 MPa Entropy Temperature

State Unknown ! Phase Steam high pressure high temperatur known - Tz = 450°c 13 - 2800.3 kJ/kg 5396.069 kJ/kg P₂ = 4 MPa Temperature Steam h4 = 1890.67 kJ/kg low pressure 54 -6.069 Kolka low temperater P4 = 7.5 kPa.