Numerical study of a swirl gas turbine combustor for turbulent air and oxy-combustion of ammonia/kerosene fuels

Abstract

Since ammonia has a carbon-free substance and involves hydrogen atoms per volume unit, many scientists think it could be used as an alternative fuel instead of natural gas or kerosene-based fuels in gas turbine combustors. The main goal of this study is to investigate turbulent swirl combustion ammonia-assisted kerosene fuels with air and pure oxygen combustion conditions in a model gas turbine combustor. For this purpose, numerical modelings have been performed by using a commercial computational fluid dynamics (CFD) code. Ammonia was introduced into the combustor from the different inlets. The ammonia composition was determined until 70% kerosene-30% ammonia mixture in an interval of 10% by heat fraction. During this addition, the total heat load provided was kept constant. The results showed that there was no considerable change over the combustion performance of kerosene. However, the maximum temperature levels and its locations changed somewhat in the combustor with ammonia addition. In addition to temperature distributions of kerosene and ammonia-assisted kerosene fuels, NOX emission levels have been addressed by performing post-processing of the CFD code used in this study. According to the predicted NOX levels, it was seen that the predicted NOX emissions levels increased significantly in the high temperature flame zone due to bound-nitrogen in ammonia (fuel-NOX mechanism). But, the predicted NOx emission levels were not too high at the exit of the combustion chamber. Therefore, it can be concluded that ammonia-assisted kerosene fuels have considerable potential in terms of combustion performance as a new and renewable fuel.