Thermodynamic and emission analysis of an ammonia fueled micro-combustor with double-channel reverse flow structure

Abstract

This study proposes a novel micro-combustor fueled by ammonia and oxygen, employing a double-channel inlet and double-channel outlet (DIDO) configuration with the reverse flow structure. The investigation delves into the parameters of the volumetric flow rate of ammonia (Qv), inlet pressure (Pin), equivalence ratio (Φ), and baffle length (d) on both nitrogen oxide emissions and thermal performance of the micro-combustor. It is observed that, in comparison to conventional systems, the DIDO combustor is capable of generating a vortex at the outlet, thereby reducing NOx emissions. Specifically, at a Qv of 900 mL/min, the NO concentration at the outlet can be curtailed by 29.23 %. Furthermore, NO emissions exhibit a gradual decline with the increase of Φ and Pin. Notably, the DIDO combustor yields a substantial enhancement in thermal performance, achieving a 51 % reduction in the standard deviation of outer wall temperature (ST,W) when Qv is set at 500 mL/min which significantly enhances the uniformity of wall temperature. The peak of thermal performance and maximum radiation efficiency (ηradiation) is reached at Φ = 0.9. The analysis of entropy production in the DIDO combustor indicates that it increases with the augmentation of Qv, while elongating the length of d augments the exergy efficiency (ηexergy).