Design and CFD analysis of a flameless combustion chamber for a 2-kW micro gas turbine
Marini, Shelon Andriel (2018)
Diplomityö
Marini, Shelon Andriel
2018
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2018052924950
https://urn.fi/URN:NBN:fi-fe2018052924950
Tiivistelmä
Motivated by the straightening regulations regarding pollutant emissions and the increasing demand for distributed generation, this thesis has the objective to develop a new combustion chamber design for 2-kWel micro gas turbines, based on flameless combustion. This concept was chosen because of its potential for very low emissions, added to the uniform temperature distribution, low noise, low vibration and the capacity to handle low-quality fuels. These features were already proven in industrial furnace applications, however, the employment of flameless combustion in gas turbines is still a research topic that requires further investigation. Two fuels were considered in this study, natural gas and landfill gas, and the evaluation and enhancement of the design is done iteratively utilizing computational fluid dynamics (CFD).
The results demonstrated that the application of flameless combustion in gas turbines is very promising. The emissions of both CO and NOx were found to be lower than 4 ppmv (in a dry basis and corrected for 15% O2). Besides, if the turbine inlet temperature can reach levels as high as 1800 K, the dilution zone of the combustor can be completely eliminated, providing a very uniform temperature profile, characteristic of flameless combustion. Nevertheless, among many problems related to efficiency in a micro gas turbine of such scale, it was found that the pressure drop of the combustor can be minimized in these cases, what could represent an increment in the electrical efficiency of almost 2%.
The results demonstrated that the application of flameless combustion in gas turbines is very promising. The emissions of both CO and NOx were found to be lower than 4 ppmv (in a dry basis and corrected for 15% O2). Besides, if the turbine inlet temperature can reach levels as high as 1800 K, the dilution zone of the combustor can be completely eliminated, providing a very uniform temperature profile, characteristic of flameless combustion. Nevertheless, among many problems related to efficiency in a micro gas turbine of such scale, it was found that the pressure drop of the combustor can be minimized in these cases, what could represent an increment in the electrical efficiency of almost 2%.