CFD-Assisted Design of an NH 3 /H 2 Combustion Chamber Based on the Rich–Quench–Lean Concept

Ammonia (NH 3 ) and hydrogen (H 2 ) are considered promising fuels for the power sector’s decarbonization. Their combustion is capable of producing energy with zero direct CO 2 emissions, and ammonia can act as a stable energy H 2 carrier. This study numerically investigates the design and implementation of staged combustion of a mixture of NH 3 /H 2 by means of CFD simulations. The investigation employed the single-phase flow RANS governing equations and the eddy dissipation concept (EDC) combustion model, with the incorporation of a detailed kinetic mechanism. The combustion chamber operates under the RQL (rich–quench–lean) combustion regime. The first stage operates under rich conditions, firing mixtures of ammonia in air, enriched by hydrogen (H 2 ) to enhance combustion properties in a swirl and bluff-body stabilized burner. The secondary stage injects additional air and hydrogen to mitigate unburnt ammonia and NO x emissions. Simulations of the first stage were performed for a thermal input ranging from 4 kW to 8 kW and flames with an equivalence ratio of 1.2. In the second stage, additional hydrogen is injected with a thermal input of either 1 kW or 2 KW, and air is added to adjust the global equivalence ratio to 0.6.