Effect of Steam Addition on the Flow Field and NOx Emissions for Jet-A in an Aircraft Combustor

Abstract

The steam injection technology for aircraft engines is gaining rising importance because of the strong limitations imposed by the legislation for NOx reduction in airports. In order to investigate the impact of steam addition on combustion and NOx emissions, an integrated performance-CFD-chemical reactor network (CRN) methodology was developed. The CFD results showed steam addition reduced the high temperature size and the radical pool moved downstream. Then different post-processing techniques are employed and CRN is generated to predict NOx emissions. This network consists of 14 chemical reactor elements and the results were in close agreement with the ICAO databank. The established CRN model was then used for steam addition study and the results showed under air/steam mixture atmosphere, high steam content could push the NOx formation region to the post-flame zone and a large amount of the NOx emission could be reduced when the steam mass fraction is quite high.

Comparative Study of the Structure and Height of CH4 Laminar Diffusion Flames: Effects of Fuel-Side versus Air-Side Dilution

“…Notably, in the pursuit of a carbon-neutral future, advanced combustion methodologies such as steam dilution combustion and oxy-fuel combustion have emerged as highly promising. These technologies involve the enrichment of CO 2 within the flue gas, facilitating cost-effective CO 2 capture. − …”

A Simplified Chemical Reactor Network Approach for Aeroengine Combustion Chamber Modeling and Preliminary Design

“…State-of-the-art CRN models consist of PSRs, especially when it comes to models with potential to be incorporated within design loops performed for combustion chamber preliminary sizing [8,23,24]. In particular, concerning the simulation of the most physically complex region of the combustor, the primary zone (PZ) within which the flame front occurs, the authors favor the use of PaSR due to the need to model the significant fluctuations occurring in the mixing quality within this turbulent zone.…”

“…In particular, concerning the simulation of the most physically complex region of the combustor, the primary zone (PZ) within which the flame front occurs, the authors favor the use of PaSR due to the need to model the significant fluctuations occurring in the mixing quality within this turbulent zone. In the literature, these PaSRs are often constructed as a series of parallel [8,10,24] or recirculating [23] PSRs, with each reactor network trying to replicate the corresponding flow field's stream lines. Each reactor, forming the aforementioned PSRs for the PZ, is simulating a fraction of the overall combustion, with a FAR following a discretized Gaussian distribution, thus recreating the effect of the imperfect mixing of fuel-air mixture [24].…”

“…The use of PFRs for modeling the whole burner is less frequent but still implemented [25] in cases with weak turbulent mixing. For the secondary (SZ) and the dilution zones (DZs), up to two serial PSRs or one PFR are used [8,23,24], thereby considering that an almost perfectly mixed gas flows through them.…”

“…On the one hand, simplified, also known as surrogate reaction mechanisms with less potential species and possible reactions are implemented to decrease the range of estimated pollutant emissions to also reduce its cost [10]. On the other hand, detailed mechanisms, taking into account all possibly occuring species and subreactions occurring within the simulated global reaction, have also been employed in recent work [8,[23][24][25].…”