Neglect the changes in kinetic energy at inlet and outlet of the turbine and pump a)For the reversible cycl thermal nce 293 =0489 573 To find the work in the pump(compression process)or in the turbine, we need to find the enthalpy changes between states b and c, Ahbe, and the change between a and d, Ah had. To obtain these the approach is to use the fact that s=constant during the expansion to find the quality at state c and then, knowing the quality, calculate the enthalpy as h=Xh, +(1-X)h. We know the conditions at state b, where the fluid is all vapor, i.e., we know Tb, hb, Sb hb=vapor( 300C)=he(300C)=2749 kJ/kg s=5(900005-05k/kgK in the isentropic expansion pi We now need to find the quality at state c, X. Using the definition of quality given in Section 2.B. 1, and noting that se=Xse+(1-x)s, we obtain, s4-s/(T)s-s/(T) The quantity s, is the mass-weighted entropy at state c, which is at temperature Tc The quantity s, (T )is the entropy of the liquid at temperature T The quantity s(T)is the entropy of the gas(vapor)at temperature T The quantity△s(T) We know Sb=5.7045 kJ/kg S/g=83706k/kg-k se=0.2966 kJ/kg-K The quality at state c is thus 5.7045-0.2966 0.646 8.3706 The enthalpy at state c is,2B-10 Neglect the changes in kinetic energy at inlet and outlet of the turbine and pump. a) For the reversible cycle, η η thermal Carnot T T = =− =− = 1 1 293 573 0 489 1 2 . To find the work in the pump (compression process) or in the turbine, we need to find the enthalpy changes between states b and c, ∆hbc , and the change between a and d, ∆had . To obtain these the approach is to use the fact that s = constant during the expansion to find the quality at state c and then, knowing the quality, calculate the enthalpy as h Xh X h = +− g f ( ) 1 . We know the conditions at state b, where the fluid is all vapor, i.e., we know Ths b bb , , : hh Ch C b vapor o g o = ( ) 300 300 2749 kJ/kg = ( ) = s s Cs C b vapor o g o = ( ) 300 300 5 7045 = ( ) = . kJ/kg - K s s b c = in the isentropic expansion process. We now need to find the quality at state c, Xc . Using the definition of quality given in Section 2.B.1, and noting that s Xs X s c cg c = +− ( ) f 1 , we obtain, X s sT sT sT s sT s T c c f c g c f c c f c fg c = − ( ) ( ) − ( ) = − ( ) ( ) . The quantity sc is the mass-weighted entropy at state c, which is at temperature Tc. The quantity s T f ( ) c is the entropy of the liquid at temperature Tc . The quantity s T g c ( ) is the entropy of the gas (vapor) at temperature Tc . The quantity ∆ ∆ sT s T fg ( ) c = liquid gas → c at . We know: s s c b = = 5.7045 kJ/kg - K sfg = 8.3706 kJ/kg - K sf = 0.2966 kJ/kg - K. The quality at state c is thus, Xc = − = 5 7045 0 2966 8 3706 0 646 . . . . . The enthalpy at state c is