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This study examines hydrogen-enriched kerosene combustion under distributed regime in a gas turbine combustion chamber. With hydrogen enrichment, it is aimed at increasing combustion performance of those fuels. However, in this circumstance, it is obvious to increase the flame temperature with taking place hydrogen enrichment. Thus colorless distributed combustion (CDC), which is one of the advanced combustion techniques, can be suggested to control flame temperature with slowing down the reaction rate, resulting in ultra-low NOX emissions and more uniform temperature distribution with a broadened flame. For this purpose, the hydrogen-enriched kerosene fuels were examined by modeling a CFD code using the eddy dissipation concept, the radiation model (P-1) and the turbulence model (standard k-epsilon). In this way, the thermal fields and the NOX distributions have been obtained. The results showed that hydrogen enrichment increased the flame temperatures from about 2490 K to 2605 K at air-combustion conditions until 30% H-2, resulting in the NOX levels predicted increased in the combustor. With reducing oxygen percentage the flame started to be the broadened one. The flame temperatures decreased, for instance, from about 2605 K to 2230 K at 15% O-2 for the 30% H-2 containing fuel. As a result of this, the NOX levels reduced from about 30 ppm to the values lower than 1 ppm in the combustor. It is concluded that increments in temperature and NOX levels with hydrogen can be suppressed with distributed regime, which enables that gas turbines can be operated at wider flammability limits with hydrogen enrichment.& nbsp;(c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

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.

In this paper, numerical simulations of a full scale concept supersonic combustor using kerosene fuel are presented. Results are reported first for a baseline model. These results are then used for identifying the shortcomings in this model, which allows improvements to be made. In particular, the spacing between the ramps is widened so that the heat addition is not confined to a short region and is distributed over a larger volume. Also the design of fuel supply lines has been reworked so that they do not obstruct the supersonic flow. Details of the flow field inside the combustor such as contours of static pressure, static temperature, species mass fraction, reaction rate and Mach number are discussed. Wall static pressure distribution along the top wall of the combustor is presented. Intricate details of the flow field such as separation zones, shocks and expansion fans and their interaction are also brought out. Finally, thrust developed by the combustor is calculated using two different methods. Copyright � 2009 Inderscience Publishers.