Page 154 - Handbook of Energy Engineering Calculations

takes place along 1-2′; actual heat added 2′-3′; ideal expansion 3′-4′.

FIGURE 14 Ideal gas-turbine cycle T-S diagram with the same
processes as in Fig. 13; complete-cycle gas turbine shown below the T-S
diagram.

(a) Here we have isentropic compression in the compressor with an

efficiency of 85 percent. Using the equation, efficiency, isentropic = (c )(T −
2
p
T )/(c ) (T - T ), and solve for T the temperature after isentropic
p
2′
1
2′
1
compression. Solving, T = 0.82 = 0.24(772.7 - 520)/0.24(T - 520) =
2′
2′
828.4°R, or 368°F. This is the temperature after compression.
3. Determine the temperature after combustion
To find the temperature after combustion, use the relation heating value of
fuel = Q = c (T - T ), where T = temperature after combustion,°R.
3′
3′
2′
p
Substituting, 200 = 0.24(T - 828). Solving, T = 1661.3°R; 1201.3°F
3′
3′
(649.6°C).