Study of inter-sector spray flame propagation in a linear arrangement of swirled burners

Driven by pollutant emissions stringent regulations, engine manufacturers rely on lean combustion and aim to reduce the number of injectors, both affecting the light-round phase of ignition. This work focuses on inter-injector spray flame propagation in a linear multi-injector n-heptane/air spray burner measured at CORIA. Large Eddy Simulation (LES) are performed together with a complex chemistry description and a Lagrangian formalism of the spray in order to account for fuel droplet polydispersion. First, a non-reacting case enables to evaluate the numerical approach by comparison with measurements, and to analyse the influence of inter-injector spacing on both the flow dynamics and the local fuel distribution. Second, the comparison of numerical fully transient ignition sequences with experimental data shows that LES recovers the inter injector spray propagation features found in the experiment such as flame propagation modes from radial to progressively arc-like, and total ignition time delay. However due to important pre-evaporation, liquid fuel does not significantly impact the overall ignition process, which exhibits the same driving mechanisms as in purely gaseous flows. (c) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

This study focuses on inter-injector spray flame propagation in a linear multi-injector n-heptane/air spray burner, using Large Eddy Simulation and complex chemistry description to investigate the influence of inter-injector spacing on flow dynamics and local fuel distribution. The results suggest that the characteristics of inter-injector spray propagation can be accurately captured by LES, with important pre-evaporation impacting the ignition process.