Page 111 - Advanced Gas Turbine Cycles

84 Advanced gas turbine cycles

with all the irreversibilities shown sums to unity again. The combustion loss remains high
at some 30%, and the HP turbine loss is not negligible.

5.9. Conclusions

In practice, the attainment of maximum thermal efficiency in a CBT gas turbine plant
will depend on a complex mix of factors in addition to those for an uncooled plant, such as
combustion temperature, pressure ratio and component efficiencies. The factors
introduced by turbine cooling include the number of cooling steps, the quantities of
cooling air required (crucially dependent on stagnation temperature at entry to each step,
the permissible blade temperature and the temperature of the available cooling air), and
the associated mixing losses. In addition, the properties of the working fluids (as real
gases) also play an important part.

References

[I] Holland, M.J. and Thake, T.F. (1980). Rotor blade cooling in high pressure turbines, AIAA J. of Aircraft
17(6), 412-418.
[2] Horlock, J.H., Watson, D.T. and Jones, T.V. (2001). Limitations on gas turbine performance imposed by
large turbine cooling flows, ASME J. Engng Gas Turbines Power 123.4.
131 Wilcock, R.C., Young, J.B. and Horlock, J.H. (2002), Gas properties as a limit to gas turbine performance,
ASME paper GT-2002-305 17.
[4] El-Masri, M.A. and Pourkey, F. (1986). Prediction of cooling flow requirements for advanced utility gas
turbines, Part 1 : Analysis and scaling of the effectiveness curve, ASME paper 86-WAlHT-43.
[SI El-Masri, M.A. (1986a). Prediction of cooling flow requirements for advanced utility gas turbines, Part 2:
Influence of ceramic thermal barrier coatings, ASME paper 86-WA/HT-44.
[6] El-Masri, M.A. (1986b). On thermodynamics of gas turbine cycles: Part I second law analysis of combined
cycles, ASME J. Engng Power Gas Turbines 107, 880-889.
[7] El-Masri, M.A. (1986~). On thermodynamics of gas turbine cycles: Part 11 Model for expansion in cooled
turbines, ASME J. Engng Power Gas Turbines 108, 15 1 - 159.
181 El-Masri, M.A. (1988). GASCAN-an interactive code for thermal analysis of gas turbine systems, ASME
J. Engng Power Gas Turbines 1 10,201 -209.
(91 El-Man, M.A. (1987a). Exergy analysis of combined cycles: Part 1 Air-cooled Brayton-cycle gas turbines,
ASME J. Engng Power Gas Turbines 109, 228-235.
[IO] El-Masri, M.A. (1987b). Exergy analysis of combined cycles: Part 2. Steam bottoming cycles, ASME J.
Engng Power Gas Turbines 109, 237-243.
[I 1 ] Chiesa, P., Consonni, S., Lozza, G. and Macchi, E. (I 993). Predicting the ultimate performance of advanced
power cycles based on very high temperatures, ASME Paper 93-GT-223.
[ 121 MacArthur, C. D. (1999). Advanced aero-engine turbine technologies and their application to industrial gas
turbines, ISABE Paper No. 99-7 IS I. 14th International Symposium on Air-Breathing Engines, Florence,
Italy, 1999.
[I31 Facchini, B., Fiaschi, D. and Manfrida, G. (2000). Exergy analysis of combined cycles using latest
generation gas turbines, ASME J. Engng Gas Turbines Power 122,233-238.
[ 141 Horlock, J.H., Manfrida, G. and Young, J.B. (2000). Exergy analysis of modem fossil-fuel power plants,
ASME J. Engng Gas Turbines Power 122, 1 - 17.
[IS] Young, J.B. and Wilcock, R.C. (2002). Modelling the air-cooled gas turbine. Part I4neral
thermodynamics, ASME J. Turbomachinery 124.207-213.