Journal of Energy in Southern Africa
versión On-line ISSN 2413-3051
versión impresa ISSN 1021-447X
MAHAPATRA, Alok K y SANJAY, B E. Performance analysis of an air humidifier integrated gas turbine with film air cooling of turbine blade. J. energy South. Afr. [online]. 2013, vol.24, n.4, pp.71-81. ISSN 2413-3051.
A computational analysis to investigate the effects of compressor pressure ratio, turbine inlet temperature, ambient relative humidity and ambient temperature on the performance parameters of an air cooled gas turbine cycle with evaporative cooling of inlet air has been presented. The blade cooling method selected is film cooling. The analysis indicates that the mass of coolant required for blade cooling is reduced with increase in temperature drop across the humidifier. Both decrease in ambient temperature and ambient relative humidity results in an increase in plant efficiency and plant specific work. The highest efficiency is obtained at a turbine inlet temperature of 1500 K for all range of ambient relative humidity and ambient temperature, beyond which it decreases. The compressor pressure ratio corresponding to the maximum plant specific work, however, varies with both ambient relative humidity and ambient temperature. The increase in specific work due to drop in ambient relative humidity is more pronounced at higher pressure ratios. Similarly, the increase in efficiency due to ambient temperature drop is prominent at higher turbine inlet temperatures. Finally, a design nomograph is presented to select the design parameters corresponding to best efficiency and specific work.
Palabras clave : inlet-air cooling; air-humidifier; gas turbine; evaporative cooling; parametric analysis; air-film blade cooling.