Page 54 - Advanced Gas Turbine Cycles

Chapter 3. Basic gas turbine cycles 31

- -[CHwR T3/Tl=4

CARNOT T-l= 4
--- [CHTXIR T-1 = 6.25

CARNOT T3/T1 = 6.25

1 1.5 2 2.5 3 3.5 4 4.5
ISENTROPIC TEMPERATURE RATIO
Fig. 3.3. Thermal efficiencies of closed reversible cycles.

)f two types of elementary cycles, 1,2,3,4” and 4”, 4/, 3/, 4. The efficiency of the latter
:ycle is 17 = 1 - ( l/xA), where xA = T4,/T4n = T3,/T4; it is less than that of the former
:ycle 77 = 1 - (l/x) and the overall efficiency of the ‘combined’ cycle is therefore

T T
3 3‘

4

1
S S
a b
Fig. 3.4. T, s diagram for reheating added to reversible simple and recuperative cycles.